--- 1/draft-ietf-lisp-threats-03.txt 2013-02-25 21:36:09.851709548 +0100
+++ 2/draft-ietf-lisp-threats-04.txt 2013-02-25 21:36:09.907707732 +0100
@@ -1,152 +1,187 @@
Network Working Group D. Saucez
Internet-Draft INRIA
Intended status: Informational L. Iannone
-Expires: April 19, 2013 Telecom ParisTech
+Expires: August 29, 2013 Telecom ParisTech
O. Bonaventure
Universite catholique de Louvain
- October 16, 2012
+ February 25, 2013
LISP Threats Analysis
- draft-ietf-lisp-threats-03.txt
+ draft-ietf-lisp-threats-04.txt
Abstract
- This document analyzes the threats against the security of the
- Locator/Identifier Separation Protocol (LISP) and proposes a set of
- recommendations to mitigate some of the identified security risks.
+ This document analyzes the potential threats against the security of
+ the Locator/Identifier Separation Protocol (LISP) if deployed in the
+ Internet. This document proposes a set of recommendations to
+ mitigate the identified security risks and keep a security level
+ equivalent to what is observed in the Internet today (i.e., without
+ LISP). By following the recommendations of this draft a LISP
+ deployment can achieve a security level that is comparable to the
+ existing Internet architecture.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
- This Internet-Draft will expire on April 19, 2013.
+ This Internet-Draft will expire on August 29, 2013.
Copyright Notice
- Copyright (c) 2012 IETF Trust and the persons identified as the
+ Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
- 2. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 3
+ 2. Definition of Terms . . . . . . . . . . . . . . . . . . . . . 4
3. On-path Attackers . . . . . . . . . . . . . . . . . . . . . . 4
- 4. Off-Path Attackers: Reference Environment . . . . . . . . . . 4
+ 4. Off-Path Attackers: Reference Environment . . . . . . . . . . 5
5. Data-Plane Threats . . . . . . . . . . . . . . . . . . . . . . 6
- 5.1. EID-to-RLOC Database Threats . . . . . . . . . . . . . . . 6
+ 5.1. EID-to-RLOC Database Threats . . . . . . . . . . . . . . . 7
5.2. EID-to-RLOC Cache Threats . . . . . . . . . . . . . . . . 7
5.2.1. EID-to-RLOC Cache poisoning . . . . . . . . . . . . . 7
5.2.2. EID-to-RLOC Cache overflow . . . . . . . . . . . . . . 9
- 5.3. Attacks not leveraging on the LISP header . . . . . . . . 9
+ 5.3. Attacks not leveraging on the LISP header . . . . . . . . 10
5.4. Attacks leveraging on the LISP header . . . . . . . . . . 10
5.4.1. Attacks using the Locator Status Bits . . . . . . . . 10
- 5.4.2. Attacks using the Map-Version bit . . . . . . . . . . 11
+ 5.4.2. Attacks using the Map-Version bit . . . . . . . . . . 12
5.4.3. Attacks using the Nonce-Present and the Echo-Nonce
- bits . . . . . . . . . . . . . . . . . . . . . . . . . 12
- 5.4.4. Attacks using the ID Instance bits . . . . . . . . . . 13
- 6. Control Plane Threats . . . . . . . . . . . . . . . . . . . . 13
- 6.1. Attacks with Map-Request messages . . . . . . . . . . . . 13
- 6.2. Attacks with Map-Reply messages . . . . . . . . . . . . . 15
- 6.3. Gleaning Attacks . . . . . . . . . . . . . . . . . . . . . 16
- 7. Threats concerning Interworking . . . . . . . . . . . . . . . 17
- 8. Threats with Malicious xTRs . . . . . . . . . . . . . . . . . 18
- 9. Security of the Proposed Mapping Systems . . . . . . . . . . . 21
- 9.1. LISP+ALT . . . . . . . . . . . . . . . . . . . . . . . . . 21
- 9.2. LISP-DDT . . . . . . . . . . . . . . . . . . . . . . . . . 22
- 10. Threats concerning LISP-MS . . . . . . . . . . . . . . . . . . 23
- 10.1. Map Server . . . . . . . . . . . . . . . . . . . . . . . . 23
- 10.2. Map Resolver . . . . . . . . . . . . . . . . . . . . . . . 24
- 11. Suggested Recommendations . . . . . . . . . . . . . . . . . . 26
- 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 28
- 13. Security Considerations . . . . . . . . . . . . . . . . . . . 28
- 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 28
- 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 28
- 15.1. Normative References . . . . . . . . . . . . . . . . . . . 28
- 15.2. Informative References . . . . . . . . . . . . . . . . . . 29
- Appendix A. Document Change Log . . . . . . . . . . . . . . . . . 30
- Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 31
+ bits . . . . . . . . . . . . . . . . . . . . . . . . . 13
+ 5.4.4. Attacks using the Instance ID bits . . . . . . . . . . 14
+ 6. Control Plane Threats . . . . . . . . . . . . . . . . . . . . 14
+ 6.1. Attacks with Map-Request messages . . . . . . . . . . . . 14
+ 6.2. Attacks with Map-Reply messages . . . . . . . . . . . . . 16
+ 6.3. Gleaning Attacks . . . . . . . . . . . . . . . . . . . . . 17
+ 7. Threats concerning Interworking . . . . . . . . . . . . . . . 18
+ 8. Threats with Malicious xTRs . . . . . . . . . . . . . . . . . 19
+ 9. Security of the Proposed Mapping Systems . . . . . . . . . . . 23
+ 9.1. LISP+ALT . . . . . . . . . . . . . . . . . . . . . . . . . 23
+ 9.2. LISP-DDT . . . . . . . . . . . . . . . . . . . . . . . . . 24
+ 10. Threats concerning LISP-MS . . . . . . . . . . . . . . . . . . 25
+ 10.1. Map Server . . . . . . . . . . . . . . . . . . . . . . . . 25
+ 10.2. Map Resolver . . . . . . . . . . . . . . . . . . . . . . . 26
+ 11. Security Recommendations . . . . . . . . . . . . . . . . . . . 28
+ 12. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 30
+ 13. Security Considerations . . . . . . . . . . . . . . . . . . . 30
+ 14. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 30
+ 15. References . . . . . . . . . . . . . . . . . . . . . . . . . . 31
+ 15.1. Normative References . . . . . . . . . . . . . . . . . . . 31
+ 15.2. Informative References . . . . . . . . . . . . . . . . . . 31
+ Appendix A. Document Change Log . . . . . . . . . . . . . . . . . 32
+ Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 34
1. Introduction
- The Locator/ID Separation Protocol (LISP) is defined in
- [I-D.ietf-lisp]. The present document aims at assessing the security
- level and identifying security threats in the LISP specification. As
- a result of the performed analysis, the document also proposes some
- recommendations aiming at improving LISP's resiliency against off-
- path attackers.
+ The Locator/ID Separation Protocol (LISP) is defined in [RFC6830].
+ The present document assesses the security level and identifies
+ security threats in the LISP specification if LISP is deployed in the
+ Internet (i.e., a public non-trustable environment). As a result of
+ the performed analysis, the document determines the severity of the
+ threats and proposes recommendations to reach the same level of
+ security in LISP than in Internet today (e.g., without LISP).
- The document is composed of two main parts: the first discussing the
- LISP data-plane; while the second discussing the LISP control-plane.
+ The document is composed of three main parts: the first discussing
+ the LISP data-plane; while the second discussing the LISP control-
+ plane. The final part summarizes the recommendations to prevent the
+ identified threats.
The LISP data-plane consists of LISP packet encapsulation,
decapsulation, and forwarding and includes the EID-to-RLOC Cache and
EID-to-RLOC Database data structures used to perform these
operations.
The LISP control-plane consists in the mapping distribution system,
which can be one of the mapping distribution systems proposed so far
- (e.g., [I-D.ietf-lisp], [I-D.fuller-lisp-ddt], [I-D.ietf-lisp-alt],
- [I-D.ietf-lisp-ms], [I-D.meyer-lisp-cons], and [I-D.lear-lisp-nerd]),
- and the Map-Request, Map-Reply, Map-Register, and Map-Notification
- messages.
+ (e.g., [RFC6830], [I-D.ietf-lisp-ddt], [RFC6836], [RFC6833],
+ [I-D.meyer-lisp-cons], and [RFC6837]), and the Map-Request, Map-
+ Reply, Map-Register, and Map-Notification messages.
This document does not consider all the possible uses of LISP as
- discussed in [I-D.ietf-lisp]. The document focuses on LISP unicast,
- including as well LISP Interworking [I-D.ietf-lisp-interworking],
- LISP-MS [I-D.ietf-lisp-ms], LISP Map-Versioning
- [I-D.ietf-lisp-map-versioning], and briefly considering the ALT
- mapping system described in [I-D.ietf-lisp-alt] and the Delegated
- Database Tree mapping system described in [I-D.fuller-lisp-ddt]. The
- reading of these documents is a prerequisite for understanding the
- present document.
+ discussed in [RFC6830]. The document focuses on LISP unicast,
+ including as well LISP Interworking [RFC6832], LISP-MS [RFC6833],
+ LISP Map-Versioning [RFC6834], and briefly considering the ALT
+ mapping system described in [RFC6836] and the Delegated Database Tree
+ mapping system described in [I-D.ietf-lisp-ddt]. The reading of
+ these documents is a prerequisite for understanding the present
+ document.
Unless otherwise stated, the document assumes a generic IP service
and does not discuss the difference, from a security viewpoint,
between using IPv4 or IPv6.
+ This document has identified several threats on LISP in the case of
+ public deployments. However, most of the threats can be prevented
+ with careful deployment and configuration. Moreover, several threats
+ are introduced by optimization techniques that can be deactivated in
+ public deployments of LISP without alteration of its functioning as
+ these techniques are designed for LISP deployments in private
+ trustable environments. Finally, this document has not identified
+ any threats that would require a change in the LISP protocol or
+ architecture.
+
2. Definition of Terms
- The present document does not introduce any new term, compared to the
- main LISP specification. For a complete list of terms please refer
- to [I-D.ietf-lisp].
+ Severity level: this document specifies the severity level of every
+ identified threat. We identified four severity levels for the
+ threats.
+
+ Level 0: the threat is not introduced by LISP and is equivalent to
+ what is encountered without LISP.
+
+ Level 1: the threat is introduced by LISP but can be neutralized by
+ configuration or deployment techniques, i.e., LISP protocol and
+ architecture does not need to be reconsidered for public
+ deployment.
+
+ Level 2: the threat is introduced by LISP but can be avoided by
+ deactivating the feature in public deployment.
+
+ Level 3: the threat is introduced by LISP and cannot be avoided
+ without changing the LISP specification or architecture.
+
+ The present document does not introduce any other new term, compared
+ to the main LISP specification. For a complete list of terms please
+ refer to [RFC6830].
3. On-path Attackers
On-path attackers are attackers that are able to capture and modify
all the packets exchanged between an Ingress Tunnel Router (ITR) and
an Egress Tunnel Router (ETR). To cope with such an attacker,
cryptographic techniques such as those used by IPSec ([RFC4301]) are
- required. We do not consider that LISP has to cope with such kind of
- attackers.
+ required. As with IP, LISP relies on higher layer cryptography to
+ secure packet payloads from on path attacks, so we do not consider
+ on-path attackers in this document.
Mobile IP has also considered time-shifted attacks from on-path
attackers. A time-shifted attack is an attack where the attacker is
temporarily on the path between two communicating hosts. While it is
on-path, the attacker sends specially crafted packets or modifies
packets exchanged by the communicating hosts in order to disturb the
packet flow (e.g., by performing a man in the middle attack). An
important issue for time-shifted attacks is the duration of the
attack once the attacker has left the path between the two
communicating hosts. We do not consider time-shifted attacks in this
@@ -205,237 +240,258 @@
assigned IP address. SA stands for Spoofing Attacker.
NSA is an off-path attacker that is only able to send packets whose
source address is its assigned IP address. NSA stands for Non
Spoofing Attacker.
It should be noted that with LISP, packet spoofing is slightly
different than in the current Internet. Generally the term "spoofed
packet" indicates a packet containing a source IP address that is not
the one of the actual originator of the packet. Since LISP uses
- encapsulation, the spoofed address can be in the outer header as well
- as in the inner header, this translates in two types of spoofing:
+ encapsulation, the spoofed address could be in the outer header as
+ well as in the inner header, this translates in two types of
+ spoofing:
EID Spoofing: the originator of the packet puts in it a spoofed EID.
The packet will be normally encapsulated by the ITR of the site
(or a PITR if the source site is not LISP enabled).
RLOC Spoofing: the originator of the packet generates directly a
LISP-encapsulated packet with a spoofed source RLOC.
Note that the two types of spoofing are not mutually exclusive,
- rather all combinations are possible and can be used to perform
+ rather all combinations are possible and could be used to perform
different kind of attacks.
In the reference environment, both SA and NSA attackers are capable
of sending LISP encapsulated data packets and LISP control packets.
This means that SA is able to perform both RLOC and EID spoofing
while NSA can only perform EID spoofing. They may also send other
types of IP packets such as ICMP messages. We assume that both
attackers can query the LISP mapping system (e.g., through a public
Map Resolver) to obtain the mappings for both HA and HB.
5. Data-Plane Threats
This section discusses threats and attacks related to the LISP data-
plane. More precisely, we discuss the operations of encapsulation,
decapsulation, and forwarding as well as the content of the EID-to-
RLOC Cache and EID-to-RLOC Database as specified in the original LISP
- document ([I-D.ietf-lisp]).
+ document ([RFC6830]).
We start considering the two main data structures of LISP, namely the
EID-to-RLOC Database and the EID-to-RLOC Cache. Then, we look at the
data plane attacks that can be performed by a spoofing off-path
attacker (SA) and discuss how they can be mitigated by LISP xTRs. In
this analysis, we assume that the LR1 and LR2 (resp. LR3 and LR4)
xTRs maintain an EID-to-RLOC Cache that contains the required mapping
entries to allow HA and HB to exchange packets.
5.1. EID-to-RLOC Database Threats
The EID-to-RLOC Database on each xTR maintains the set of mappings
related to the EID-Prefixes that are "behind" the xTR. Where
"behind" means that at least one of the xTR's globally visible IP
addresses is a RLOC for those EID-Prefixes.
- As described in [I-D.ietf-lisp], the EID-to-RLOC Database content is
+ As described in [RFC6830], the EID-to-RLOC Database content is
determined by configuration. This means that the only way to attack
this data structure is by gaining privileged access to the xTR. As
such, it is out of the scope of LISP to propose any mechanism to
protect routers and, hence, it is no further analyzed in this
document.
+ Severity level 0.
+
5.2. EID-to-RLOC Cache Threats
- A key component of the overall LISP architecture is the EID-to-RLOC
- Cache. The EID-to-RLOC Cache is the data structure that stores the
- bindings between EID and RLOC (namely the "mappings") to be used
- later on. Attacks against this data structure can happen either when
- the mappings are first installed in the cache (see also Section 6) or
- by corrupting (poisoning) the mappings already present in the cache.
+ The EID-to-RLOC Cache (also called the Map-Cache) is the data
+ structure that stores a copy of the mappings retrieved from a remote
+ ETR's mapping database via the LISP control plane. Attacks against
+ this data structure could happen either when the mappings are first
+ installed in the cache (see also Section 6) or by corrupting
+ (poisoning) the mappings already present in the cache.
+
+ Severity level 2. The severity level of EID-to-RLOC Cache Threats
+ depends on the attack vector as described below.
5.2.1. EID-to-RLOC Cache poisoning
- The content of the EID-to-RLOC Cache can be poisoned by spoofing LISP
- encapsulated packets. Examples of EID-to-RLOC Cache poisoning are:
+ The content of the EID-to-RLOC Cache could be poisoned by spoofing
+ LISP encapsulated packets. Examples of EID-to-RLOC Cache poisoning
+ are:
Fake mapping: The cache contains entirely fake mappings that do not
- originate from an authoritative mapping server. This can be
+ originate from an authoritative mapping server. This could be
achieved either through gleaning as described in Section 6.3 or
by attacking the control-plane as described in Section 6.
EID Poisoning: The EID-Prefix in a specific mapping is not owned by
the originator of the entry. Similarly to the previous case,
- this can be achieved either through gleaning as described in
+ this could be achieved either through gleaning as described in
Section 6.3 or by attacking the control-plane as described in
Section 6.
EID redirection/RLOC poisoning: The EID-Prefix in the mapping is not
bound to (located by) the set of RLOCs present in the mapping.
- This can result in packets being redirected elsewhere,
- eavesdropped, or even blackholed. Note that not necessarily
+ This could result in packets being redirected elsewhere,
+ eavesdropped, or even black-holed. Note that not necessarily
all RLOCs are fake/spoofed. The attack works also if only part
of the RLOCs, the highest priority ones, is compromised.
- Again, this can be achieved either through the gleaning as
+ Again, this could be achieved either through the gleaning as
described in Section 6.3 or by attacking the control-plane as
described in Section 6.
Reachability poisoning: The reachability information stored in the
mapping could be poisoned, redirecting the packets to a subset
of the RLOCs (or even stopping it if locator status bits are
all set to 0). If reachability information is not verified
- through the control-plane this attack can be simply achieved by
+ through the control-plane this attack could be achieved by
sending a spoofed packet with swapped or all locator status
- bits reset. The same result can be obtained by attacking the
+ bits reset. The same result could be obtained by attacking the
control-plane as described in Section 6. Depending on how the
RLOC reachability information is stored on the router, the
- attack can impact only one mapping or all the mappings that
+ attack could impact only one mapping or all the mappings that
share the same RLOC.
Traffic Engineering information poisoning: The LISP protocol defines
two attributes associated to each RLOC in order to perform
inbound Traffic Engineering (TE), namely priority and weight.
By injecting fake TE attributes, the attacker is able to break
load balancing policies and concentrate all the traffic on a
single RLOC or put more load on a RLOC than what is expected,
creating congestion. It is even possible to block the traffic
if all the priorities are set to 255 (special value indicating
- not to use the RLOC). Corrupting the TE attributes can be
+ not to use the RLOC). Corrupting the TE attributes could be
achieved by attacking the control-plane as described in
Section 6.
Mapping TTL poisoning: The LISP protocol associates a Time-To-Live
to each mapping that, once expired, allows to delete a mapping
from the EID-to-RLOC Cache (or forces a Map-Request/Map-Reply
exchange to refresh it if still needed). By injecting fake TTL
- values, an attacker can either shrink the EID-to-RLOC Cache
+ values, an attacker could either shrink the EID-to-RLOC Cache
(using very short TTL), thus creating an excess of cache miss
- causing a DoS on the mapping system, or it can increase the
+ causing a DoS on the mapping system, or it could increase the
size of the cache by putting very high TTL values, up to a
- cache overflow (see Section 5.2.2). Corrupting the TTL can be
- achieved by attacking the control-plane as described in
- Section 6. Long TTL can be use in fake mappings to increase
+ cache overflow (see Section 5.2.2). Corrupting the TTL could
+ be achieved by attacking the control-plane as described in
+ Section 6. Long TTL could be used in fake mappings to increase
attack duration.
Instance ID poisoning: The LISP protocol allows using a 24-bit
identifier to select the forwarding table to use on the
decapsulating ETR to forward the decapsulated packet. By
- spoofing this attribute the attacker is able to redirect or
- blackhole inbound traffic. Corrupting the Instance ID
- attribute can be achieved by attacking the control-plane as
- described in Section 6.
+ spoofing this attribute the attacker might cause traffic to be
+ either dropped or decapsulated and then placed into the
+ incorrect VRF at the destination ETR. Corrupting the Instance
+ ID attribute could be achieved by attacking the control-plane
+ as described in Section 6.
- Map-Version poisoning: The LISP protocol allows associating a
- version number to mappings ([I-D.ietf-lisp-map-versioning]).
- The LISP header can transport source and destination map-
- versions, describing which version of the mapping have been
- used to select the source and the destination RLOCs of the LISP
+ Map-Version poisoning: The LISP protocol offers the option to
+ associate a version number to mappings ([RFC6834]). The LISP
+ header can transport source and destination map-versions,
+ describing which version of the mapping have been used to
+ select the source and the destination RLOCs of the LISP
encapsulated packet. By spoofing this attribute the attacker
is able to trigger Map-Request on the receiving ETR.
- Corrupting the Map-Version attribute can be achieved either by
- attacking the control-plane as described in Section 6 or by
+ Corrupting the Map-Version attribute could be achieved either
+ by attacking the control-plane as described in Section 6 or by
using spoofed packets as described in Section 5.4.2.
- If the above listed attacks succeed, the attacker has the means of
- controlling the traffic.
+ If the ITR's map-cache is compromised (likely via compromising the
+ LISP control-plane) it is possible that traffic in the data-plane may
+ be redirected (encapsulated to the wrong destination) a or dropped by
+ the ITR.
+
+ If data-plane redirection is of a critical concern, then deploying
+ some sort of IPSEC or TLS based security on a layer above LISP (just
+ like you would on top of IP) is recommended.
5.2.2. EID-to-RLOC Cache overflow
Depending on how the EID-to-RLOC Cache is managed (e.g., Least
Recently Used - LRU vs. Least Frequently Used - LFU) and depending on
- its size, an attacker can try to fill the cache with fake mappings.
+ its size, an attacker could try to fill the cache with fake mappings.
Once the cache is full, some mappings will be replaced by new fake
ones, causing traffic disruption.
- This can be achieved either through gleaning as described in
+ This could be achieved either through gleaning as described in
Section 6.3 or by attacking the control-plane as described in
Section 6.
Another way to generate an EID-to-RLOC Cache overflow is by injecting
mapping with a fake and very large TTL value. In this case the cache
will keep a large amount of mappings ending with a completely full
- cache. This type of attack can also be performed through the
+ cache. This type of attack could also be performed through the
control-plane.
5.3. Attacks not leveraging on the LISP header
We first consider an attacker that sends packets without exploiting
the LISP header, i.e., with the N, L, E, V, and I bits reset
- ([I-D.ietf-lisp]).
+ ([RFC6830]).
To inject a packet in the HA-HB flow, a spoofing off-path attacker
- (SA) can send a LISP encapsulated packet whose source is set to LR1
+ (SA) could send a LISP encapsulated packet whose source is set to LR1
or LR2 and destination LR3 or LR4. The packet will reach HB as if
the packet was sent by host HA. This is not different from today's
Internet where a spoofing off-path attacker may inject data packets
- in any flow. Several existing techniques can be used by hosts to
+ in any flow. Several existing techniques could be used by hosts to
prevent such attacks from affecting established flows, e.g.,
[RFC4301] and [I-D.ietf-tcpm-tcp-security].
- On the other hand, a non-spoofing off-path attacker (NSA) can only
+ On the other hand, a non-spoofing off-path attacker (NSA) could only
send a packet whose source address is set to its assigned IP address.
- The destination address of the encapsulated packet can be LR3 or LR4.
- When the LISP ETR that serves HB receives the encapsulated packet, it
- can consult its EID-to-RLOC Cache and verify that NSA is not a valid
- source address for LISP encapsulated packets containing a packet sent
- by HA. This verification is only possible if the ETR already has a
- valid mapping for HA. Otherwise, and to avoid such data packet
- injection attacks, the LISP ETR should reject the packet and possibly
- query the mapping system to obtain a mapping for the encapsulated
- source EID (HA).
+ The destination address of the encapsulated packet could be LR3 or
+ LR4. When the LISP ETR that serves HB receives the encapsulated
+ packet, it can consult its EID-to-RLOC Cache and verify that NSA is
+ not a valid source address for LISP encapsulated packets containing a
+ packet sent by HA. This verification is only possible if the ETR
+ already has a valid mapping for HA. Otherwise, and to avoid such
+ data packet injection attacks, the LISP ETR should reject the packet
+ and possibly query the mapping system to obtain a mapping for the
+ encapsulated source EID (HA).
+
+ Severity level 1: use well known anti-spoofing techniques and
+ configure ETRs to verify the that RLOCs and EIDs are consistent with
+ the entries in the EID-to-RLOC Cache.
5.4. Attacks leveraging on the LISP header
- The main LISP document [I-D.ietf-lisp] defines several flags that
- modify the interpretation of the LISP header in data packets. In
- this section, we discuss how an off-path attacker could exploit this
- LISP header.
+ The main LISP document [RFC6830] defines several flags that modify
+ the interpretation of the LISP header in data packets. In this
+ section, we discuss how an off-path attacker could exploit this LISP
+ header.
+
+ Severity level 2. The severity level of attacks leveraging on the
+ LISP header depends on the attack vector as described below.
5.4.1. Attacks using the Locator Status Bits
When the L bit is set to 1, it indicates that the second 32-bits
longword of the LISP header contains the Locator Status Bits. In
this field, each bit position reflects the status of one of the RLOCs
mapped to the source EID found in the encapsulated packet. In
particular, a packet with the L bit set and all Locator Status Bits
set to zero indicates that none of the locators of the encapsulated
source EID are reachable. The reaction of a LISP ETR that receives
- such a packet is not clearly described in [I-D.ietf-lisp].
+ such a packet is not clearly described in [RFC6830].
- A spoofing off-path attacker (SA) can send a data packet with the L
+ A spoofing off-path attacker (SA) could send a data packet with the L
bit set to 1, all Locator Status Bits set to zero, a spoofed source
RLOC (e.g. LR1), destination LR3, and containing an encapsulated
packet whose source is HA. If LR3 blindly trusts the Locator Status
Bits of the received packet it will set LR1 and LR2 as unreachable,
possibly disrupting ongoing communication.
- Locator Status Bits can be blindly trusted only in secure
+ Locator Status Bits could be blindly trusted only in secure
environments. In the general unsecured Internet environment, the
safest practice for xTRs is to confirm the reachability change
through the control plane (e.g., RLOC probing). In the above
example, LR3 should note that something has changed in the Locator
Status Bits and query the mapping system (assuming it is trusted) in
order to confirm status of the RLOCs of the source EID.
A similar attack could occur by setting only one Locator Status Bit
to 1, e.g., the one that corresponds to the source RLOC of the
packet.
@@ -446,73 +502,83 @@
in Section 5.3, if the xTR accepts the packet without checking the
EID-to-RLOC Cache for a mapping that binds the source EID and the
source RLOC of the received packet, then the same observation like
for the spoofing attacker (SA) apply with the difference that instead
of complete disruption, the traffic will flow through only one RLOC,
possibly resulting in a DoS attack.
Otherwise, if the xTR does make the check through the EID-to-RLOC
Cache, it should reject the packet because its source address is not
one of the addresses listed as RLOCs for the source EID.
- Nevertheless, in this case a Map-Request should be sent, which can be
- used to perform Denial of Service attacks. Indeed an attacker can
- frequently change the Locator Status Bits in order to trigger a large
- amount of Map-Requests. Rate limitation, as described in
- [I-D.ietf-lisp], does not allow sending high number of such a
- request, resulting in the attacker saturating the rate with these
- spoofed packets.
+ Nevertheless, in this case a Map-Request should be sent, which could
+ be used to perform Denial of Service attacks. Indeed an attacker
+ could frequently change the Locator Status Bits in order to trigger a
+ large amount of Map-Requests. Rate limitation, as described in
+ [RFC6830], if implemented in a very simple way a single bucket for
+ all triggered control plane messages, does not allow sending high
+ number of such a request, resulting in the attacker saturating the
+ rate with these spoofed packets.
+
+ Severity level 2: to avoid any risk, Locator Status Bits should be
+ deactivated in public deployments of LISP. Deactivating LSB does not
+ reduce LISP functionality.
5.4.2. Attacks using the Map-Version bit
- The Map-Version bit is used to indicate whether the low-order 24 bits
- of the first 32 bits longword of the LISP header contain a Source and
- Destination Map-Version. When a LISP ETR receives a LISP
- encapsulated packet with the Map-Version bit set to 1, the following
- actions are taken:
+ The optional Map-Version bit is used to indicate whether the low-
+ order 24 bits of the first 32 bits longword of the LISP header
+ contain a Source and Destination Map-Version. When a LISP ETR
+ receives a LISP encapsulated packet with the Map-Version bit set to
+ 1, the following actions are taken:
o It compares the Destination Map-Version found in the header with
the current version of its own mapping, in the EID-to-RLOC
Database, for the destination EID found in the encapsulated
packet. If the received Destination Map-Version is smaller (i.e.,
older) than the current version, the ETR should apply the SMR
- procedure described in [I-D.ietf-lisp] and send a Map-Request with
- the SMR bit set.
+ procedure described in [RFC6830] and send a Map-Request with the
+ SMR bit set.
o If a mapping exists in the EID-to-RLOC Cache for the source EID,
then it compares the Map-Version of that entry with the Source
Map-Version found in the header of the packet. If the stored
mapping is older (i.e., the Map-Version is smaller) than the
source version of the LISP encapsulated packet, the xTR should
send a Map-Request for the source EID.
A spoofing off-path attacker (SA) could use the Map-Version bit to
- force an ETR to send Map-Request messages. The attacker can retrieve
- the current source and destination Map-Version for both HA and HB.
- Based on this information, it can send a spoofed packet with an older
- Source Map-Version or Destination Map-Version. If the size of the
- Map-Request message is larger than the size of the smallest LISP-
- encapsulated packet that could trigger such a message, this could
- lead to amplification attacks (see Section 6.1). However,
- [I-D.ietf-lisp] recommends to rate limit the Map-Request messages
- that are sent by an xTR. This prevents the amplification attack, but
- there is a risk of Denial of Service attack if an attacker sends
- packets with Source and Destination Map-Versions that frequently
- change. In this case, the ETR could consume its entire rate by
- sending Map-Request messages in response to these spoofed packets.
+ force an ETR to send Map-Request messages. The attacker could
+ retrieve the current source and destination Map-Version for both HA
+ and HB. Based on this information, it could send a spoofed packet
+ with an older Source Map-Version or Destination Map-Version. If the
+ size of the Map-Request message is larger than the size of the
+ smallest LISP-encapsulated packet that could trigger such a message,
+ this could lead to amplification attacks (see Section 6.1). However,
+ [RFC6830] recommends to rate limit the Map-Request messages that are
+ sent by an xTR. This prevents the amplification attack, but there is
+ a risk of Denial of Service attack if an attacker sends packets with
+ Source and Destination Map-Versions that frequently change. In this
+ case, and depending on the implementation of the rate limitation
+ policy, the ETR might consume its entire rate by sending Map-Request
+ messages in response to these spoofed packets.
- A non-spoofing off-path attacker (NSA) cannot success in such an
+ A non-spoofing off-path attacker (NSA) could not success in such an
attack if the destination xTR rejects the LISP encapsulated packets
that are not sent by one of the RLOCs mapped to the included source
- EID. If it is not the case, the attacker can be able to perform
+ EID. If it is not the case, the attacker could be able to perform
attacks concerning the Destination Map Version number as for the
spoofing off-path attacker (SA).
+ Severity level 1: the correct deployment of anti-spoofing and rate
+ limitation techniques prevents the attacks leveraging on the Map-
+ Version.
+
5.4.3. Attacks using the Nonce-Present and the Echo-Nonce bits
The Nonce-Present and Echo-Nonce bits are used when verifying the
reachability of a remote ETR. Assume that LR3 wants to verify that
LR1 receives the packets that it sends. LR3 can set the Echo-Nonce
and the Nonce-Present bits in LISP data encapsulated packets and
include a random nonce in these packets. Upon reception of these
packets, LR1 will store the nonce sent by LR3 and echo it when it
returns LISP encapsulated data packets to LR3.
@@ -550,57 +616,68 @@
will consider the ETR not reachable. The success of this test will
of course depend on the ratio between the amount of packets sent by
the legitimate ITR and the spoofing off-path attacker (SA).
Packets sent by a non-spoofing off-path attacker (NSA) can cause
similar problem if no check is done with the EID-to-RLOC Cache (see
Section 5.3 for the EID-to-RLOC Cache check). Otherwise, if the
check is performed the packets will be rejected by the ETR that
receives them and cannot cause problems.
-5.4.4. Attacks using the ID Instance bits
+ Severity level 2: to avoid any problem, echo nonce should be
+ deactivated. Deactivating echo-nonce does not reduce LISP
+ functionality as it is an optimization for symmetric data flow path
+ and because other techniques exist to test the reachability of a
+ RLOC.
+
+5.4.4. Attacks using the Instance ID bits
LISP allows to carry in its header a 24-bits value called "Instance
ID" and used on the ITR to indicate which private Instance ID has
been used for encapsulation, while on the ETR can be used to select
the forwarding table used for forwarding the decapsulated packet.
Even if an off-path attacker could randomly guess a valid Instance ID
value, there is no LISP specific problem. Obviously the attacker
could be now able to reach hosts that are only reachable through the
routing table identified by the attacked Instance ID, however, end-
system security is out of the scope of this document. Nevertheless,
access lists can be configured to protect the network from Instance
ID based attacks.
+ Severity level 1: the correct deployment of access control lists and
+ firewalls prevent the attacks leveraging on the Instance ID.
+
6. Control Plane Threats
- In this section, we discuss the different types of attacks that can
+ In this section, we discuss the different types of attacks that could
occur when an off-path attacker sends control plane packets. We
focus on the packets that are sent directly to the ETR and do not
analyze the particularities of a LISP mapping system. The LISP+ALT
and LISP-DDT mapping systems are discussed in Section 9.
+ Severity level 2. The severity level of attacks on the LISP control-
+ plane depends on the attack vector as described below.
+
6.1. Attacks with Map-Request messages
An off-path attacker could send Map-Request packets to a victim ETR.
In theory, a Map-Request packet is only used to solicit an answer and
as such it should not lead to security problems. However, the LISP
- specification [I-D.ietf-lisp] contains several particularities that
- could be exploited by an off-path attacker.
+ specification [RFC6830] contains several particularities that could
+ be exploited by an off-path attacker.
The first possible exploitation is the P bit. The P bit is used to
- probe the reachability of remote ETRs in the control plane. In our
- reference environment, LR3 could probe the reachability of LR1 by
- sending a Map-Request with the P bit set. LR1 would reply by sending
- a Map-Reply message with the P bit set and the same nonce as in the
- Map-Request message.
+ probe the reachability of remote ETRs. In our reference environment,
+ LR3 could probe the reachability of LR1 by sending a Map-Request with
+ the P bit set. LR1 would reply by sending a Map-Reply message with
+ the P bit set and the same nonce as in the Map-Request message.
A spoofing off-path attacker (SA) could use the P bit to force a
victim ETR to send a Map-Reply to the spoofed source address of the
Map-Request message. As the Map-Reply can be larger than the Map-
Request message, there is a risk of amplification attack.
Considering only IPv6 addresses, a Map-Request can be as small as 40
bytes, considering one single ITR address and no Mapping Protocol
Data. The Map-Reply instead has a size of O(12 + (R * (28 + N *
24))) bytes, where N is the maximum number of RLOCs in a mapping and
R the maximum number of records in a Map-Reply. Since up to 255
@@ -639,81 +716,96 @@
of a Map-Request message with the SMR bit, an ETR must return to the
source of the Map-Request message a Map-Request message to retrieve
the corresponding mapping. This raises similar problems as the P bit
discussed above except that as the Map-Request messages are smaller
than Map-Reply messages, the risk of amplification attacks is
reduced. This is not true anymore if the ETR append to the Map-
Request messages its own Map-Records. This mechanism is meant to
reduce the delay in mapping distribution since mapping information is
provided in the Map-Request message.
+ Severity level 1: the correct deployment of anti-spoofing and rate
+ limitation techniques prevents the attacks leveraging the Map-Request
+ message.
+
Furthermore, appending Map-Records to Map-Request messages represents
a major security risk since an off-path attacker could generate a
(spoofed or not) Map-Request message and include in the Map-Reply
portion of the message mapping for EID prefixes that it does not
serve. This could lead to various types of redirection and denial of
service attacks. An xTR should not process the Map-Records
- information that it receives in a Map-Request message.
+ information that it receives in a Map-Request message. As it is a
+ performance optimization, we recommend to deactivate this
+ functionality in public LISP deployments.
+
+ Severity level 2: to avoid any risk, appending Map-Records to Map-
+ Request messages should be deactivated in public deployments of LISP.
+ Deactivating appending Map-Records to Map-Request messages does not
+ reduce LISP functionality.
6.2. Attacks with Map-Reply messages
In this section we analyze the attacks that could occur when an off-
path attacker sends directly Map-Reply messages to ETRs without using
one of the proposed LISP mapping systems.
There are two different types of Map-Reply messages:
Positive Map-Reply: These messages contain a Map-Record binding an
EID-Prefix to one or more RLOCs.
Negative Map-Reply: These messages contain a Map-Record for an EID-
Prefix with an empty locator-set and specifying an action,
- which may be either Drop, Natively forward, or Send Map-
+ which may be either Drop, natively forward, or Send Map-
Request.
Positive Map-Reply messages are used to map EID-Prefixes onto RLOCs.
- Negative Map-Reply messages are used to support PTR and interconnect
- the LISP Internet with the legacy Internet.
+ Negative map-reply messages are used to indicate non-lisp prefixes.
+ ITRs can, if needed, be configured to send all traffic destined for
+ non-lisp prefixes to a Proxy-ETR.
Most of the security of the Map-Reply messages depends on the 64 bits
nonce that is included in a Map-Request and returned in the Map-
Reply. An ETR must never accept a Map-Reply message whose nonce does
not match one of the pending Map-Request messages. If an ETR does
not accept Map-Reply messages with an invalid nonce, the risk of
attack is acceptable given the size of the nonce (64 bits).
- Note, however, that the nonce only confirms that the Map-Reply was
- sent by the ETR that received the Map-Request. It does not validate
- the content of the Map-Reply message.
+ The nonce only confirms that the map-reply received was sent in
+ response to a map-request sent, it does not validate the contents of
+ that map-reply.
- In addition, an attacker can perform EID-to-RLOC Cache overflow
+ In addition, an attacker could perform EID-to-RLOC Cache overflow
attack by de-aggregating (i.e., splitting an EID prefix into
artificially smaller EID prefixes) either positive or negative
mappings.
+ Severity level 1: the correct deployment of anti-spoofing techniques
+ prevents attacks leveraging the Map-Reply message.
+
6.3. Gleaning Attacks
A third type of attack involves the gleaning mechanism proposed in
- [I-D.ietf-lisp] and discussed in [Saucez09]. In order to reduce the
- time required to obtain a mapping, [I-D.ietf-lisp] allows an ITR to
- learn a mapping from the LISP data encapsulated packets and the Map-
- Request packets that it receives. LISP data encapsulated packet
- contains a source RLOC, destination RLOC, source EID and destination
- EID. When an ITR receives a data encapsulated packet coming from a
- source EID for which it does not already know a mapping, it may
- insert the mapping between the source RLOC and the source EID in its
- EID-to-RLOC Cache. Gleaning can also be used when an ITR receives a
- Map-Request as the Map-Request also contains a source EID address and
- a source RLOC. Once a gleaned entry has been added to the EID-to-
- RLOC cache, the LISP ITR sends a Map-Request to retrieve the mapping
- for the gleaned EID from the mapping system. [I-D.ietf-lisp]
- recommends storing the gleaned entries for only a few seconds.
+ [RFC6830] and discussed in [Saucez09]. In order to reduce the time
+ required to obtain a mapping, [RFC6830] allows an ITR to learn a
+ mapping from the LISP data encapsulated packets and the Map-Request
+ packets that it receives. LISP data encapsulated packet contains a
+ source RLOC, destination RLOC, source EID and destination EID. When
+ an ITR receives a data encapsulated packet coming from a source EID
+ for which it does not already know a mapping, it may insert the
+ mapping between the source RLOC and the source EID in its EID-to-RLOC
+ Cache. Gleaning could also be used when an ITR receives a Map-
+ Request as the Map-Request also contains a source EID address and a
+ source RLOC. Once a gleaned entry has been added to the EID-to-RLOC
+ cache, the LISP ITR sends a Map-Request to retrieve the mapping for
+ the gleaned EID from the mapping system. [RFC6830] recommends
+ storing the gleaned entries for only a few seconds.
The first risk of gleaning is the ability to temporarily hijack an
identity. Consider an off-path attacker that wants to temporarily
hijack host HA's identity and send packets to host HB with host HA's
identity. If the xTRs that serve host HB do not store a mapping for
host HA, a non-spoofing off-path attacker (NSA) could send a LISP
encapsulated data packet to LR3 or LR4. The ETR will store the
gleaned entry and use it to return the packets sent by host HB to the
attacker. In parallel, the ETR will send a Map-Request to retrieve
the mapping for HA. During a few seconds or until the reception of
@@ -741,66 +833,81 @@
control plane rate limit. This will extend the duration of the
gleaned entry. If host HA establishes a flow with host HB at that
time, the packets that they exchange will first pass through the
attacker.
In both cases, the attack only lasts for a few seconds (unless the
attacker is able to exhaust the rate limitation). However it should
be noted that today a large amount of packets might be exchanged
during even a small fraction of time.
+ Severity level 2: to avoid any risk, gleaning should be deactivated
+ in public deployments of LISP. Deactivating gleaning does not reduce
+ LISP functionality.
+
7. Threats concerning Interworking
- [I-D.ietf-lisp-interworking] defines two network elements to allow
- LISP and non-LISP sites to communicate, namely the Proxy-ITR and the
- Proxy-ETR. The Proxy-ITR encapsulates traffic from non-LISP sites in
- order to forward it toward LISP sites, while the Proxy-ETR
- decapsulates traffic arriving from LISP sites in order to forward it
- toward non-LISP sites. For these elements some of the attack based
- on the LISP specific header are not possible, for the simple reason
- that some of the fields cannot be used due to the unidirectional
- nature of the traffic.
+ [RFC6832] defines two network elements to allow LISP and non-LISP
+ sites to communicate, namely the Proxy-ITR and the Proxy-ETR. The
+ Proxy-ITR encapsulates traffic from non-LISP sites in order to
+ forward it toward LISP sites, while the Proxy-ETR decapsulates
+ traffic arriving from LISP sites in order to forward it toward non-
+ LISP sites. For these elements some of the attack based on the LISP
+ specific header are not possible, for the simple reason that some of
+ the fields cannot be used due to the unidirectional nature of the
+ traffic.
- The Proxy-ITR has functionalities similar to the ITR, however, its
- main purpose is to encapsulate packets arriving from the DFZ in order
- to reach LISP sites. This means that it is no bound to any
- particular EID-Prefix, hence no mapping exists and no mapping can be
- configured in the EID-to-RLOC Database. This means that the Proxy-
- ITR element itself is not able to check whether or not the arriving
- traffic has the right to be encapsulated or not. To limit such an
- issue it is recommended to use the current practice based on
- firewalls and ACLs on the machine running the Proxy-ITR service. On
- the other side, the Proxy-ITR is meant to encapsulate only packets
- that are destined to one of the LISP sites it is serving. This is
- the case for instance for a service provider selling Proxy-ITR
- services. For this purpose a static EID-to-RLOC Cache can be
- configured in order to encapsulate only valid packets. In case of a
- cache-miss no Map-Request needs to be sent and the packet can be
- silently dropped.
+ The Proxy-ITR has functionality similar to the ITR, however, its main
+ purpose is to encapsulate packets arriving from the DFZ in order to
+ reach LISP sites. This means that it is no bound to any particular
+ EID-Prefix, hence no mapping exists and no mapping can be configured
+ in the EID-to-RLOC Database. This means that the Proxy-ITR element
+ itself is not able to check whether or not the arriving traffic has
+ the right to be encapsulated or not. To limit Proxy-ITRs being used
+ as relays for attacks, Proxy-ITRs operators are encouraged to
+ implement best practices for data plane access control on the Proxy-
+ ITRs and the border of the network, that is the edge of the scope of
+ the Proxy-ITR's announcement of the EID-Prefix. On the other side,
+ the Proxy-ITR is meant to encapsulate only packets that are destined
+ to one of the LISP sites it is serving. This is the case for
+ instance for a service provider selling Proxy-ITR services. For this
+ purpose a static EID-to-RLOC Cache can be configured in order to
+ encapsulate only valid packets. In case of a cache-miss no Map-
+ Request needs to be sent and the packet can be silently dropped.
- The Proxy-ETR has functionalities similar to the ETR, however, its
- main purpose is to inject un-encapsulated packet in the DFZ in order
- to reach non-LISP-Sites. This means that since there is no specific
+ The Proxy-ETR has functionality similar to the ETR, however, its main
+ purpose is to inject un-encapsulated packet in the DFZ in order to
+ reach non-LISP-Sites. This means that since there is no specific
EID-Prefix downstream, it has no EID-to-RLOC Database that can be
used to check whether or not the destination EID is part of its
domain. In order to avoid for the Proxy-ETR to be used as relay in a
DoS attack it is preferable to configure the EID-to-RLOC Cache with
static entries used to check if an encapsulated packet coming from a
specific RLOC and having a specific source EID is actually allowed to
transit through the Proxy-ETR. This is also important for services
provider selling Proxy-ETR service to actually process only packets
arriving from its customers. However, in case of cache-miss no Map-
Request needs to be sent, rather the packet can be silently dropped
since it is not originating from a valid site. The same drop policy
should be used for packets with an invalid source RLOC or a valid
source RLOC but an invalid EID.
+ As it is the case without LISP, the addition of public proxies offers
+ opportunities to attackers to commit attacks. LISP interworking does
+ not open new threats compared to other interworking techniques based
+ on public proxies.
+
+ Severity level 0: the careful configuration of PETR and PITR combined
+ with the deployment of anti-spoofing techniques mitigates the attacks
+ leveraging interworking and provides the same level of severity as
+ interworking techniques in the Internet.
+
8. Threats with Malicious xTRs
In this section, we discuss the threats that could be caused by
malicious xTRs. We consider the reference environment below where
EL1 is a malicious or compromised xTR. This malicious xTR serves a
set of hosts that includes HC. The other xTRs and hosts in this
network play the same role as in the reference environment described
in Section 4.
+-----+
@@ -833,65 +940,79 @@
| |
-------------------
|
| EID: HB
+-----+
| HB |
+-----+
Figure 2: Malicious xTRs' Reference Environment
- Malicious xTRs are probably the most serious threat to the LISP
- control plane from a security viewpoint. To understand the problem,
- let us consider the following scenario. Host HC and HB exchange
- packets with host HA. As all these hosts reside in LISP sites, LR1
- and LR2 store mappings for HB and HC. Thus, these xTRs may need to
- exchange LISP control plane packets with EL1, e.g., to perform
- reachability tests or to refresh expired mappings (e.g., if HC's
- mapping has a small TTL).
+ Since xTRs are cornerstone in the LISP architecture, malicious xTRs
+ are probably the most serious threat to the LISP control plane from a
+ security viewpoint. Indeed, the impact of compromised LISP Control
+ Plane can be severe, and the most effective way to attack any multi-
+ organizational control plane is from within the system itself. To
+ understand the problem, let us consider the following scenario. Host
+ HC and HB exchange packets with host HA. As all these hosts reside
+ in LISP sites, LR1 and LR2 store mappings for HB and HC. Thus, these
+ xTRs may need to exchange LISP control plane packets with EL1, e.g.,
+ to perform reachability tests or to refresh expired mappings (e.g.,
+ if HC's mapping has a small TTL).
A first threat against the LISP control plane is when EL1 replies to
a legitimate Map-Request message sent by LR1 or LR2 with a Map-Reply
message that contains an EID-Prefix that is larger than the prefix
owned by the site attached to EL1. For instance if the prefix owned
by EL1 is 192.0.2.0/25 but the Map-Reply contain a mapping for
192.0.2.0/24. This could allow EL1 to attract packets destined to
other EIDs than the EIDs that are attached to EL1. This attack is
called an "overclaiming" attack.
- Overclaiming attack can be combined with de-aggregation to succeed a
- LISP Cache poisoning attack and prefix hijacking. For example, if
+ A malicious ETR might fragment its eid-to-rloc database and then
+ instigate traffic to its site, therefore creating state on the
+ corresponding ITR's map-cache. This attack is called de-aggregation
+ attack.
+
+ Overclaiming attack could be combined with de-aggregation to succeed
+ a LISP Cache poisoning attack and prefix hijacking. For example, if
the EID prefix of the attacker is 192.0.2.0/25, it cannot provide a
mapping for the EID prefix 192.0.2.128/25 (i.e., it cannot hijack the
prefix). However, since a Map-Reply can contain several map records,
it is possible to hijack such a prefix by providing as well a mapping
- for it. To this end, the attacker can send a Map-Reply with an EID
+ for it. To this end, the attacker could send a Map-Reply with an EID
prefix that covers at the same time the requested EID and the
hijacked target prefix. Continuing the previous example, if the
requested mapping is for EID 192.0.2.1, and the target hijack prefix
is 192.0.2.128/25, the Map-Reply will contain a map record for
192.0.2.0/24 and a map record for 192.0.2.128/25. Such a reply is
considered legitimate according to the requested EID, while the map
record of the hijacked prefix may lead to traffic redirection/
disruption and ITR's Cache poisoning.
Another variant of the overclaiming attack is a Denial of Service
attack by sending a Negative Map-Reply message for a larger prefix
without any locator and with the Drop action. Such a Negative Map-
Reply indicates that the ETR that receives it should discard all
packets.
- The current LISP specification briefly discusses the overclaiming
- problem [I-D.ietf-lisp], but does not propose any specific solution
- to solve the problem. Nevertheless, [I-D.ietf-lisp-sec] proposes a
- solution to protect LISP against overclaiming attacks under the
- assumption that the mapping system can be trusted.
+ By enabling [I-D.ietf-lisp-sec], overclaiming attacks are mitigated
+ under the assumption that the mapping system can be trusted. This
+ assumption is equivalent to the general assumption that the control-
+ plane is trustable in BGP meaning that the threat is not more severe
+ than what is observed today. In addition, at the time of the writing
+ all Map Server implementations are configured with the minimal prefix
+ allowed to be register by their customers such that a customer cannot
+ register an overclaimed attack. Therefore, if mappings are always
+ retrieved via the mapping system with LISP-Sec activated and if Map-
+ Registers are cryptographically protected as recommended in the
+ specifications, overclaiming attack is not possible.
Another concern with malicious xTRs is the possibility of Denial of
Service attacks. A first attack is the flooding attack that was
described in [I-D.bagnulo-lisp-threat]. This attack allows a
malicious xTR to redirect traffic to a victim. The malicious xTR
first defines a mapping for HC with two RLOCs: its own RLOC (EL1) and
the RLOC of the victim (e.g., LR3). The victim's RLOC is set as
unreachable in the mapping. HC starts a large download from host HA.
Once the download starts, the malicious xTR updates its Locator
Status Bits, changes the mapping's version number or sets the SMR bit
@@ -904,37 +1025,45 @@
An important point to note about this flooding attack is that it
reveals a limitation of the LISP architecture. A LISP ITR relies on
the received mapping and possible reachability information to select
the RLOC of the ETR that it uses to reach a given EID or block of
EIDs. However, if the ITR made a mistake, e.g., due to
misconfiguration, wrong implementation, or other types of errors and
has chosen a RLOC that does not serve the destination EID, there is
no easy way for the LISP ETR to inform the ITR of its mistake. A
possible solution is to enforce an ETR to perform a reachability test
with the selected ITR as soon as there is LISP encapsulated traffic
- between the two.
+ between the two. We recommend to never use reachability information
+ without verifying them first.
Note that the attacks discussed in this section are for documentation
purpose only. Malicious xTRs are either somehow directly deployed by
attackers or the result of attackers gaining privileged access to
existing xTRs. As such, it is out of the scope of LISP to propose
any mechanism to protect routers or to avoid their deployments with
malicious intentions.
+ Severity level 2: the correct deployment of anti-spoofing and rate
+ limiting techniques combined with LISP-Sec and Map-Register
+ authentication prevents threats caused by malicious xTRs, as long as
+ mappings are always retrieved via a trustable mapping system. In
+ addition reachability information should never been used without
+ being verified first.
+
9. Security of the Proposed Mapping Systems
9.1. LISP+ALT
- One of the assumptions in [I-D.ietf-lisp] is that the mapping system
- is more secure than sending Map-Request and Map-Reply messages
- directly. We analyze this assumption in this section by analyzing
- the security of the ALT mapping system.
+ One of the assumptions in [RFC6830] is that the mapping system is
+ more secure than sending Map-Request and Map-Reply messages directly.
+ We analyze this assumption in this section by analyzing the security
+ of the ALT mapping system.
The ALT mapping system is basically a manually configured overlay of
GRE tunnels between ALT routers. BGP sessions are established
between ALT routers that are connected through such tunnels. An ALT
router advertises the EID prefixes that it serves over its BGP
sessions with neighboring ALT routers and the EID-Prefixes that it
has learned from neighboring ALT routers.
The ALT mapping system is in fact a discovery system that allows any
ALT router to discover the ALT router that is responsible for a given
@@ -946,135 +1075,151 @@
This ALT router then replies directly by sending a Map-Reply to the
RLOC of the requesting ITR.
The security of the ALT mapping system depends on many factors,
including:
o The security of the intermediate ALT routers.
o The validity of the BGP advertisements sent on the ALT overlay.
- Unfortunately, experience with BGP on the global Internet has shown
- that BGP is subject to various types of misconfiguration problems and
- security attacks. The SIDR working group is developing a more secure
- inter-domain routing architecture to solve this problem ([RFC6480]).
+ ALT routers are interconnected with tunnels, the usage of secured
+ tunnels prevents BGP advertisements to be altered, dropped, or added
+ by on-path or off path attackers. If a high level of security is
+ required, works in the SIDR working group that develop security
+ solutions for BGP ([RFC6480]) could be applied to LISP+ALT.
The security of the intermediate ALT routers is another concern. A
malicious intermediate ALT router could manipulate the received BGP
advertisements and also answer to received Map-Requests without
forwarding them to their final destination on the overlay. This
could lead to various types of redirection attacks. Note that in
contrast with a regular IP router that could also manipulate in
transit packets, when a malicious or compromised ALT router replies
to a Map-Request, it can redirect legitimate traffic for a long
period of time by sending an invalid Map-Reply message. Thus, the
- impact of a malicious ALT router could be much more severe than a
- malicious router in today's Internet.
+ impact of a malicious ALT router could be more severe than a
+ malicious router in today's Internet. BGP is also weak in case of a
+ router involved in the BGP topology is compromised.
+
+ Severity level 1: configuring correctly the Map Servers, Map
+ Revolvers, and ALT routers with filters corresponding to their
+ customer cones provides the same security level as in BGP. If more
+ security is necessary, cryptography must be used to validate the
+ mappings themselves.
9.2. LISP-DDT
The LISP Delegated Database Tree (LISP-DDT) mapping system is
- proposed as an alternative for LISP+ALT [I-D.fuller-lisp-ddt]. LISP-
+ proposed as an alternative for LISP+ALT [I-D.ietf-lisp-ddt]. LISP-
DDT is a hierarchical distributed database for EID-to-RLOC mappings.
Each DDT node is configured with an EID prefix it is authoritative
for, as well as the RLOC addresses and EID prefixes of the LISP-DDT
nodes that are authoritative for more specific EID prefix. In LISP-
- DDT, mappings are retrieved iteratively. A Map Resolver that needs
- to locate a mapping traverses the tree of DDT nodes contacting them
- one after another until the leaf of the DDT tree that is
- authoritative for the longest matching EID prefix for the mapping's
- EID is reached. The Map Resolver traverses the hierarchy of LISP-DDT
- nodes by sending Map-Requests, with the LISP-DDT-originated bit set,
- to LISP-DDT nodes. The Map Resolver first contacts the root of the
- hierarchy. When a LISP-DDT node receives a Map-Request, it replies
- to the Map Resolver with a Map-Referral that contains the list of the
- locators of its children that are authoritative of a prefix that
- covers the EID in the Map-Request. The Map Resolver then contacts
- one of these children that will return, at its turn, a Map-Referral.
- This procedure is iteratively executed until a Map-Referral marked
- with the done flag is received. The locators that appear in a
- referral with the done flag are those of the authoritative ETRs for
- the EID in the Map-Request. At that moment, the Map Resolver falls
- back to its normal behavior and sends a Map-Request to the ETR in
- order for the ITR to obtain the mapping. It is worth to mention that
- the Map Resolver can cache the referrals to avoid traversing all the
- whole hierarchy for all mapping retrievals.
+ DDT, mappings are retrieved iterative. A Map Resolver that needs to
+ locate a mapping traverses the tree of DDT nodes contacting them one
+ after another until the leaf of the DDT tree that is authoritative
+ for the longest matching EID prefix for the mapping's EID is reached.
+ The Map Resolver traverses the hierarchy of LISP-DDT nodes by sending
+ Map-Requests, with the LISP-DDT-originated bit set, to LISP-DDT
+ nodes. The Map Resolver first contacts the root of the hierarchy.
+ When a LISP-DDT node receives a Map-Request, it replies to the Map
+ Resolver with a Map-Referral that contains the list of the locators
+ of its children that are authoritative of a prefix that covers the
+ EID in the Map-Request. The Map Resolver then contacts one of these
+ children that will return, at its turn, a Map-Referral. This
+ procedure is iteratively executed until a Map-Referral marked with
+ the done flag is received. The locators that appear in a referral
+ with the done flag are those of the authoritative ETRs for the EID in
+ the Map-Request. At that moment, the Map Resolver falls back to its
+ normal behavior and sends a Map-Request to the ETR in order for the
+ ITR to obtain the mapping. It is worth to mention that the Map
+ Resolver can cache the referrals to avoid traversing all the whole
+ hierarchy for all mapping retrievals.
The operation in LISP-DDT is different from ALT and thus it does not
present the same threats as LISP+ALT. As a first difference, LISP-
DDT natively includes security specification providing data origin
authentication, data integrity protection and secure EID prefix
delegation. Hence, these aspects are no further explored in this
document.
However, threats exist for LISP-DDT as well. For instance, a DoS
- attack can be performed on the mapping infrastructure by asking to
+ attack could be performed on the mapping infrastructure by asking to
retrieve a large amount of mappings at the same time, hence, the
importance of carefully dimensioning the topology of the DDT
hierarchy.
- If an attacker manages to compromise a LISP-DDT node it can send fake
- referrals to the Map Resolver and then control the mappings delivered
- to the ITRs. Furthermore, the effects of such an attack can be
- longer than the attack itself if the Map Resolver caches the
+ If an attacker manages to compromise a LISP-DDT node it could send
+ fake referrals to the Map Resolver and then control the mappings
+ delivered to the ITRs. Furthermore, the effects of such an attack
+ could be longer than the attack itself if the Map Resolver caches the
referrals.
+ Severity level 1: the correct deployment of anti-spoofing and rate
+ limiting techniques combined with embedded security features of LISP-
+ DDT prevent attacks leveraging LISP-DDT.
+
10. Threats concerning LISP-MS
- LISP-MS ([I-D.ietf-lisp-ms] specifies two network elements, namely
- the Map Server and the Map Resolver, that are meant to be used by
- xTRs to access the mapping system. The advantage is clearly the fact
- that even if the mapping system changes in time xTRs do not need to
- change anything since they deal only with Map Servers and Map
- Resolvers. This includes the security aspects, since no change in
- the local security policies is needed.
+ LISP-MS ([RFC6833] specifies two network elements, namely the Map
+ Server and the Map Resolver, that are meant to be used by xTRs to
+ access the mapping system. The advantage is clearly the fact that
+ even if the mapping system changes in time xTRs do not need to change
+ anything since they deal only with Map Servers and Map Resolvers.
+ This includes the security aspects, since no change in the local
+ security policies is needed.
10.1. Map Server
Map Server is used to dispatch Map-Request coming from the mapping
system to ETRs that are authoritative for the EID in the request. To
this end it is necessary that ETRs register their mappings to the Map
Server. This allows the Map Server to know toward which ETR to
forward Map-Requests and also to announce the EID-prefixes of the
registered mappings in the mapping system.
LISP uses a shared key approach in order to protect the Map Server
and grant registration rights only to ETRs that have a valid key.
Shared key must be used to protect both the registration message and
the Map-Notify message when used. The mechanism used to share the
key between a Map Server and an ETRs must be secured to avoid that a
malicious nodes catch the key and uses it to send forged Map-Register
- message to the Map Server. A forged Map-Register message can be use
- to attract Map-Request and thus provide invalid Map-Replies or the
- redirect Map-Requests to a target to mount a DoS attack.
+ message to the Map Server. A forged Map-Register message could be
+ used to attract Map-Request and thus provide invalid Map-Replies or
+ the redirect Map-Requests to a target to mount a DoS attack.
- More subtle attacks can be carried out only in the case of malicious
- ETRs. A malicious ETR can register an invalid RLOC to divert Map-
- Requests to a target ETR and succeed a DoS attack on it. To avoid
- this kind of attack, the Map Server must check that the registered
- RLOCs belong to ETRs authoritative for the registered EID prefix.
- Such check can be done by sending and explicit Map-Request for the
- EID to the ETRs in the mapping and check that replies with a Map-
- Reply. If the ETRs return a valid Map-Reply, the RLOC belongs to an
- authoritative ETR. Note that this does not protect against malicious
- ETRs that create forged Map-Replies. Stronger techniques for RLOC
- check are presented in [I-D.saucez-lisp-mapping-security].
+ More subtle attacks could be carried out only in the case of
+ malicious ETRs. A malicious ETR could register an invalid RLOC to
+ divert Map-Requests to a target ETR and succeed a DoS attack on it.
+ To avoid this kind of attack, the Map Server must check that the
+ registered RLOCs belong to ETRs authoritative for the registered EID
+ prefix. Such check can be done by sending and explicit Map-Request
+ for the EID to the ETRs in the mapping and check that replies with a
+ Map-Reply. If the ETRs return a valid Map-Reply, the RLOC belongs to
+ an authoritative ETR. Note that this does not protect against
+ malicious ETRs that create forged Map-Replies. Stronger techniques
+ for RLOC check are presented in [I-D.saucez-lisp-mapping-security].
- Similarly to the previous case, a malicious ETR can register an
+ Similarly to the previous case, a malicious ETR could register an
invalid EID-prefix to attract Map-Requests or to redirect them to a
target to mount a DoS attack. To avoid this kind of attack, the Map
Server must check that the prefixes registered by an ETR belong to
that ETR. One method could be to manually configure EID-prefix
ranges that can be announced by ETRs.
[I-D.saucez-lisp-mapping-security] present alternative techniques to
verify the prefix claimed by an ETR.
+ Severity level 1: the correct deployment of anti-spoofing and rate
+ limiting techniques combined with usage of Map-Register
+ authentication prevents attacks leveraging the Map Server.
+
10.2. Map Resolver
Map Resolvers receive Map-Requests, typically from ITRs, and use the
mapping system to find a mapping for the EID in the Map-Request. It
can work in two modes:
Non-Caching Mode: The resolver just forwards the Map-Request to the
mapping system, which will take care of delivering the request
to an authoritative ETR. The latter will send back a Map-Reply
directly to the ITR that has originally issued the request.
@@ -1083,70 +1228,83 @@
it to the mapping system. In this way it will receive the
corresponding reply, store a local copy in a cache, and send
back a reply to the original requester. Since all requested
mappings are locally cached, before actually making a request
to the mapping system it performs a lookup in the local cache
and in case of an hit, it send back a reply without querying
the mapping system.
In its basic mode, i.e., non-caching mode, the Map Resolver does not
keep state, hence, the only direct form of attack is a DoS attack,
- where an attacker (or a group of attackers) can try to exhaust
+ where an attacker (or a group of attackers) could try to exhaust
computational power by flooding the resolver with requests. Common
- filtering techniques and BCP against DoS attacks can be applied in
+ filtering techniques and BCP against DoS attacks could be applied in
this case.
- Nonetheless, attackers can use resolvers as relay for DoS attacks
- against xTRs. An off-path spoofing attacker can generate a high load
- of requests to a set of resolvers, hence distributing the load in
- order to avoid to be blocked. All this requests can use a specific
- EID that makes all the requests to be forwarded to a specific ETR,
- which, as a result, will be victim of a DDoS attack. Similarly, the
- attacker can use a spoofed source address making all the replies to
- converge to one single ITR, which, as a result, will be victim of a
- DDoS attack. Such scenarios are not specific to LISP, but rather a
- common problem of every query infrastructure, hence the same BCP can
- be applied in order to limit the attacks.
+ Nonetheless, attackers could use resolvers as relay for DoS attacks
+ against xTRs. An off-path spoofing attacker could generate a high
+ load of requests to a set of resolvers, hence distributing the load
+ in order to avoid to be blocked. All this requests can use a
+ specific EID that makes all the requests to be forwarded to a
+ specific ETR, which, as a result, will be victim of a DDoS attack.
+ Similarly, the attacker could use a spoofed source address making all
+ the replies to converge to one single ITR, which, as a result, will
+ be victim of a DDoS attack. Such scenarios are not specific to LISP,
+ but rather a common problem of every query infrastructure, hence the
+ same BCP can be applied in order to limit the attacks.
When functioning in caching-mode, the resolver will use the same type
of cache than ITRs. Due to its similarity with the ITRs' cache the
analysis provided in Section 5.2 holds also in this case. However,
an important difference exists: this cache is not used for packet
encapsulation but only for quick replies when new requests arrive.
Therefore, as the caching-mode is only an optimization, the attacks
that aim at filling the Map Resolver cache have a less severe impact
- on the traffic.
+ on the traffic. The usage of LISP-Sec prevents ITR to obtain invalid
+ mappings. It is worth noting that caching is not used in current
+ implementations as it makes mapping synchronization hard for mobile
+ devices.
When Map Resolvers are used as front-end of the LIS-DDT mapping
system they may be exposed to another variant of DoS. Indeed, the
iterative operation of the Map Resolver on the DDT hierarchy implies
that it has to maintain state about the ITR that requested the
mapping, this in order to send the final Map-Request to the ETR on
behalf of the ITR. An attacker might leverage on this to fill the
- Map Resolver memory and then cause a DoS.
+ Map Resolver memory and then cause a DoS. Rate limiting can be used
+ to present this attack.
The question may arise on whether a Kaminsky-like attack is possible
for an off-path attacker against ITRs sending requests to a certain
resolver. The 64-bits nonce present in every message has been
introduced in the LISP specification to avoid such kind of attack.
There has been discussion within the LISP Working Group on the
optimal size of the nonce, and it seems that 64-bits provides
sufficient protection.
A possible way to limit the above-described attacks is to introduce
strong identification in the Map-Request/Map-Reply by using the
- Encapsulated Control Message with authentication enabled.
+ Encapsulated Control Message with authentication enabled
+ [I-D.ietf-lisp-sec].
-11. Suggested Recommendations
+ Severity level 1: the correct deployment of anti-spoofing and rate
+ limiting techniques combined with LISP-Sec and Map-Register
+ authentication prevent attacks leveraging Map Resolver.
- To mitigate the impact of attacks against LISP, the following
- recommendations should be followed.
+11. Security Recommendations
+
+ Different deployments of LISP may have different security
+ requirements. The recommendations in this document aim at mitigating
+ threats in in public deployments of LISP.
+
+ To mitigate the impact of attacks against LISP in public deployments,
+ the following recommendations should be followed.
First, the use of some form of filtering can help in avoid or at
least mitigate some types of attacks.
o On ETRs, packets should be decapsulated only if the destination
EID is effectively part of the EID-Prefix downstream the ETR.
Further, still on ETRs, packets should be decapsulated only if a
mapping for the source EID is present in the EID-to-RLOC Cache and
has been obtained through the mapping system (not gleaned).
@@ -1182,26 +1340,26 @@
as [RFC3704] or SAVI [SAVI], it can be expected that attackers will
become less capable of sending packets with a spoofed source address.
To prevent packet injection attacks from non-spoofing attackers
(NSA), ETRs should always verify that the source RLOC of each
received LISP data encapsulated packet corresponds to one of the
RLOCs listed in the mappings for the source EID found in the inner
packet. An alternative could be to use existing IPSec techniques
[RFC4301] and when necessary including perhaps [RFC5386] to establish
an authenticated tunnel between the ITR and the ETR.
- [I-D.ietf-lisp] recommends to rate limit the control messages that
- are sent by an xTR. This limit is important to deal with denial of
- service attacks. However, a strict limit, e.g., implemented with a
- token bucket, on all the Map-Request and Map-Reply messages sent by
- an xTR is not sufficient. An xTR should distinguish between
- different types of control plane packets:
+ [RFC6830] recommends to rate limit the control messages that are sent
+ by an xTR. This limit is important to deal with denial of service
+ attacks. However, a strict limit, e.g., implemented with a token
+ bucket, on all the Map-Request and Map-Reply messages sent by an xTR
+ is not sufficient. An xTR should distinguish between different types
+ of control plane packets:
1. The Map-Request messages that it sends to refresh expired mapping
information.
2. The Map-Request messages that it sends to obtain mapping
information because one of the served hosts tried to contact an
external EID.
3. The Map-Request messages that it sends as reachability probes.
@@ -1213,32 +1371,32 @@
These control plane messages are used for different purposes. Fixing
a global rate limit for all control plane messages increases the risk
of Denial of Service attacks if a single type of control plane
message can exceed the configured limit. This risk could be
mitigated by either specifying a rate for each of the five types of
control plane messages. Another option could be to define a maximum
rate for all control plane messages, and prioritize the control plane
messages according to the list above (with the highest priority for
message type 1).
- In [I-D.ietf-lisp], there is no mechanism that allows an xTR to
- verify the validity of the content a Map-Reply message that it
- receives. Besides the attacks discussed earlier in the document, a
- time-shifted attack where an attacker is able to modify the content
- of a Map-Reply message but then needs to move off-path could also
- create redirection attacks. The nonce only allows an xTR to verify
- that a Map-Reply responds to a previously sent Map-Request message.
- In order to allow verifying the validity and integrity of bindings
- between EID-Prefixes and their RLOCS solutions proposed in
- [I-D.saucez-lisp-mapping-security] and [I-D.ietf-lisp-sec] should be
- deployed. Having such kind of mechanisms would allow ITRs to ignore
- non-verified mappings, thus increasing security.
+ In [RFC6830], there is no mechanism that allows an xTR to verify the
+ validity of the content a Map-Reply message that it receives.
+ Besides the attacks discussed earlier in the document, a time-shifted
+ attack where an attacker is able to modify the content of a Map-Reply
+ message but then needs to move off-path could also create redirection
+ attacks. The nonce only allows an xTR to verify that a Map-Reply
+ responds to a previously sent Map-Request message. To verify the
+ validity and integrity of bindings between EID-Prefixes and their
+ RLOCS, solutions proposed in [I-D.saucez-lisp-mapping-security] and
+ [I-D.ietf-lisp-sec] could be deployed. Having LISP-SEC and lisp-
+ mapping-security in place would prevent all the above-mentioned
+ threats.
Finally, there is also the risk of Denial of Service attack against
the EID-to-RLOC Cache. We have discussed these attacks when
considering external attackers with, e.g., the gleaning mechanism and
in Section 5.2. If an ITR has a limited EID-to-RLOC Cache, a
malicious or compromised host residing in the site that it serves
could generate packets to random destinations to force the ITR to
issue a large number of Map-Requests whose answers could fill its
cache. Faced with such misbehaving hosts, LISP ITR should be able to
limit the percent of Map-Requests that it sends for a given source
@@ -1256,85 +1414,79 @@
Security considerations are the core of this document and do not need
to be further discussed in this section.
14. Acknowledgments
This document builds upon the draft of Marcelo Bagnulo
([I-D.bagnulo-lisp-threat]), where the flooding attack and the
reference environment were first described.
- We would like to thank Jeff Wheeler for his comments.
+ The authors would like to thank Vina Ermagan, Darrel Lewis, and Jeff
+ Wheeler for their comments.
This work has been partially supported by the INFSO-ICT-216372
TRILOGY Project (www.trilogy-project.org).
15. References
-
15.1. Normative References
- [I-D.fuller-lisp-ddt]
- Fuller, V., Lewis, D., Ermagan, V., and A. Jain, "LISP
- Delegated Database Tree", draft-fuller-lisp-ddt-04 (work
- in progress), September 2012.
+ [RFC6830] Farinacci, D., Fuller, V., Meyer, D., and D. Lewis, "The
+ Locator/ID Separation Protocol (LISP)", RFC 6830,
+ January 2013.
- [I-D.ietf-lisp]
- Farinacci, D., Fuller, V., Meyer, D., and D. Lewis,
- "Locator/ID Separation Protocol (LISP)",
- draft-ietf-lisp-23 (work in progress), May 2012.
+ [RFC6832] Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
+ "Interworking between Locator/ID Separation Protocol
+ (LISP) and Non-LISP Sites", RFC 6832, January 2013.
- [I-D.ietf-lisp-alt]
- Fuller, V., Farinacci, D., Meyer, D., and D. Lewis, "LISP
- Alternative Topology (LISP+ALT)", draft-ietf-lisp-alt-10
- (work in progress), December 2011.
+ [RFC6833] Fuller, V. and D. Farinacci, "Locator/ID Separation
+ Protocol (LISP) Map-Server Interface", RFC 6833,
+ January 2013.
- [I-D.ietf-lisp-interworking]
- Lewis, D., Meyer, D., Farinacci, D., and V. Fuller,
- "Interworking LISP with IPv4 and IPv6",
- draft-ietf-lisp-interworking-06 (work in progress),
- March 2012.
+ [RFC6834] Iannone, L., Saucez, D., and O. Bonaventure, "Locator/ID
+ Separation Protocol (LISP) Map-Versioning", RFC 6834,
+ January 2013.
- [I-D.ietf-lisp-map-versioning]
- Iannone, L., Saucez, D., and O. Bonaventure, "LISP Map-
- Versioning", draft-ietf-lisp-map-versioning-09 (work in
- progress), March 2012.
+ [RFC6836] Fuller, V., Farinacci, D., Meyer, D., and D. Lewis,
+ "Locator/ID Separation Protocol Alternative Logical
+ Topology (LISP+ALT)", RFC 6836, January 2013.
- [I-D.ietf-lisp-ms]
- Fuller, V. and D. Farinacci, "LISP Map Server Interface",
- draft-ietf-lisp-ms-16 (work in progress), March 2012.
+ [RFC6837] Lear, E., "NERD: A Not-so-novel Endpoint ID (EID) to
+ Routing Locator (RLOC) Database", RFC 6837, January 2013.
15.2. Informative References
[Chu] Jerry Chu, H., "Tuning TCP Parameters for the 21st
Century", 75th IETF, Stockholm, July 2009,
.
[I-D.bagnulo-lisp-threat]
Bagnulo, M., "Preliminary LISP Threat Analysis",
draft-bagnulo-lisp-threat-01 (work in progress),
July 2007.
+ [I-D.ietf-lisp-ddt]
+ Fuller, V., Lewis, D., Ermagan, V., and A. Jain, "LISP
+ Delegated Database Tree", draft-ietf-lisp-ddt-00 (work in
+ progress), October 2012.
+
[I-D.ietf-lisp-sec]
Maino, F., Ermagan, V., Cabellos-Aparicio, A., Saucez, D.,
and O. Bonaventure, "LISP-Security (LISP-SEC)",
draft-ietf-lisp-sec-04 (work in progress), October 2012.
[I-D.ietf-tcpm-tcp-security]
Gont, F., "Survey of Security Hardening Methods for
Transmission Control Protocol (TCP) Implementations",
draft-ietf-tcpm-tcp-security-03 (work in progress),
March 2012.
- [I-D.lear-lisp-nerd]
- Lear, E., "NERD: A Not-so-novel EID to RLOC Database",
- draft-lear-lisp-nerd-09 (work in progress), April 2012.
-
[I-D.meyer-lisp-cons]
Brim, S., "LISP-CONS: A Content distribution Overlay
Network Service for LISP", draft-meyer-lisp-cons-04 (work
in progress), April 2008.
[I-D.saucez-lisp-mapping-security]
Saucez, D. and O. Bonaventure, "Securing LISP Mapping
replies", draft-saucez-lisp-mapping-security-00 (work in
progress), February 2011.
@@ -1354,20 +1506,35 @@
[SAVI] IETF, "Source Address Validation Improvements Working
Group", .
[Saucez09]
Saucez, D. and L. Iannone, "How to mitigate the effect of
scans on mapping systems", Submitted to the Trilogy
Summer School on Future Internet.
Appendix A. Document Change Log
+ o Version 04 Posted February 2013.
+
+ * Clear statement that the document compares threats of public
+ LISP deployments with threats in the current Internet
+ architecture.
+
+ * Addition of a severity level discussion at the end of each
+ section.
+
+ * Addressed comments from D. Lewis' review.
+
+ * Updated References.
+
+ * Further editorial polishing.
+
o Version 03 Posted October 2012.
* Dropped Reference to RFC 2119 notation because it is not
actually used in the document.
* Deleted future plans section.
* Updated References
* Deleted/Modified sentences referring to the early status of the