[c-nsp] Cisco Security Advisory: Cisco IOS Software Mobile IP and Mobile IPv6 Vulnerabilities

Cisco Systems Product Security Incident Response Team psirt at cisco.com
Wed Mar 25 12:00:00 EDT 2009


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Cisco Security Advisory: Cisco IOS Software Mobile IP and Mobile IPv6
Vulnerabilities

Advisory ID: cisco-sa-20090325-mobileip

http://www.cisco.com/warp/public/707/cisco-sa-20090325-mobileip.shtml

Revision 1.0

For Public Release 2009 March 25 1600 UTC (GMT)

- ---------------------------------------------------------------------

Summary
=======

Devices that are running Cisco IOS Software and configured for Mobile
IP Network Address Translation (NAT) Traversal feature or Mobile IPv6
are vulnerable to a denial of service (DoS) attack that may result in
a blocked interface.

Cisco has released free software updates that address these
vulnerabilities.

This advisory is posted at the following link 
http://www.cisco.com/warp/public/707/cisco-sa-20090325-mobileip.shtml

Note: The March 25, 2009, Cisco IOS Security Advisory bundled
publication includes eight Security Advisories. All of the advisories
address vulnerabilities in Cisco IOS Software. Each advisory lists
the releases that correct the vulnerability or vulnerabilities in the
advisory. The following table lists releases that correct all Cisco
IOS Software vulnerabilities that have been published in Cisco
Security Advisories on March 25, 2009, or earlier.

http://www.cisco.com/warp/public/707/cisco-sa-20090325-bundle.shtml

Individual publication links are listed below:

  * Cisco IOS cTCP Denial of Service Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-ctcp.shtml

  * Cisco IOS Software Multiple Features IP Sockets Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-ip.shtml

  * Cisco IOS Software Mobile IP and Mobile IPv6 Vulnerabilities
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-mobileip.shtml

  * Cisco IOS Software Secure Copy Privilege Escalation Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-scp.shtml

  * Cisco IOS Software Session Initiation Protocol Denial of Service
    Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-sip.shtml

  * Cisco IOS Software Multiple Features Crafted TCP Sequence
    Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-tcp.shtml

  * Cisco IOS Software Multiple Features Crafted UDP Packet
    Vulnerability
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-udp.shtml

  * Cisco IOS Software WebVPN and SSLVPN Vulnerabilities
    http://www.cisco.com/warp/public/707/cisco-sa-20090325-webvpn.shtml

Affected Products
=================

Devices that are running an affected version of Cisco IOS Software
and configured for Mobile IP NAT Traversal feature or Mobile IPv6 are
vulnerable.

Vulnerable Products
+------------------

Devices running Cisco IOS Software and configured for Mobile IP NAT
Traversal feature will have a line similar to the following in the
output of the show running-config command:

    ip mobile home-agent nat traversal [...]

or

    ip mobile foreign-agent nat traversal [...]

or

    ip mobile router-service collocated registration nat traversal [...]

Devices running Cisco IOS Software and configured for Mobile IPv6
will have a line similar to the following in the output of the show
running-config command:

    ipv6 mobile home-agent

To determine the Cisco IOS Software release that is running on a
Cisco product, administrators can log in to the device and issue the
show version command to display the system banner. The system banner
confirms that the device is running Cisco IOS Software by displaying
text similar to "Cisco Internetwork Operating System Software" or
"Cisco IOS Software." The image name displays in parentheses,
followed by "Version" and the Cisco IOS Software release name. Other
Cisco devices do not have the show version command or may provide
different output.

The following example identifies a Cisco product that is running
Cisco IOS Software Release 12.3(26) with an installed image name of
C2500-IS-L:

        Router#show version
        Cisco Internetwork Operating System Software
        IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
        Technical Support: http://www.cisco.com/techsupport
        Copyright (c) 1986-2008 by cisco Systems, Inc.
        Compiled Mon 17-Mar-08 14:39 by dchih
        !--- output truncated


The following example identifies a Cisco product that is running
Cisco IOS Software Release 12.4(20)T with an installed image name of
C1841-ADVENTERPRISEK9-M:

        Router#show version
        Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
        Technical Support: http://www.cisco.com/techsupport
        Copyright (c) 1986-2008 by Cisco Systems, Inc.
        Compiled Thu 10-Jul-08 20:25 by prod_rel_team
        !--- output truncated


Additional information about Cisco IOS Software release naming
conventions is available in "White Paper: Cisco IOS Reference Guide"
at the following link: http://www.cisco.com/warp/public/620/1.html

Products Confirmed Not Vulnerable
+--------------------------------

Cisco IOS XR is not affected by these vulnerabilities.

Cisco IOS XE is not affected by these vulnerabilities.

No other Cisco products are currently known to be affected by these
vulnerabilities.

Details
=======

Mobile IP is part of both IPv4 and IPv6 standards. Mobile IP allows a
host device to be identified by a single IP address even though the
device may move its physical point of attachment from one network to
another. Regardless of movement between different networks,
connectivity at the different points is achieved seamlessly without
user intervention. Roaming from a wired network to a wireless or
wide-area network is also possible.

More information on Mobile IPv6 can be found at the following link:
http://www.cisco.com/en/US/docs/ios/ipv6/configuration/guide/ip6-mobile.html

The Mobile IP Support NAT Traversal feature is documented in RFC
3519. It introduces an alternative method for tunneling Mobile IP
data traffic. New extensions in the Mobile IP registration request
and reply messages have been added for establishing User Datagram
Protocol (UDP) tunneling. This feature allows mobile devices in
collocated mode that use a private IP address (RFC 1918) or foreign
agents (FAs) that use a private IP address for the care-of address
(CoA) to establish a tunnel and traverse a NAT-enabled router with
mobile node (MN) data traffic from the home agent (HA).

More information on Mobile IP NAT Traversal feature can be found at
the following link: 
http://www.cisco.com/en/US/docs/ios/12_3t/12_3t8/feature/guide/gtnatmip.html

Devices that are running an affected version of Cisco IOS Software
and configured for Mobile IPv6 or Mobile IP NAT Traversal feature are
affected by a DoS vulnerability. A successful exploitation of this
vulnerability could cause an interface to stop processing traffic
until the system is restarted. Offending packets need to be destined
to the router for a successful exploit.

These vulnerabilities are documented in the Cisco Bug IDs CSCsm97220 
and CSCso05337 and have been assigned Common Vulnerabilities and 
Exposures (CVE) IDs CVE-2009-0633 and CVE-2009-0634.

Vulnerability Scoring Details
=============================

Cisco has provided scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS). The CVSS
scoring in this Security Advisory is done in accordance with CVSS
version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability
severity and helps determine urgency and priority of response.

Cisco has provided a base and temporal score. Customers can then
compute environmental scores to assist in determining the impact of
the vulnerability in individual networks.

Cisco has provided an FAQ to answer additional questions regarding
CVSS at

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to help compute the
environmental impact for individual networks at

http://intellishield.cisco.com/security/alertmanager/cvss

CSCsm97220 - Input queue wedged by MIPv6 packets

CVSS Base Score - 7.8

 Access Vector           - Network
 Access Complexity       - Low
 Authentication          - None
 Confidentiality Impact  - None
 Integrity Impact        - None
 Availability Impact     - Complete

CVSS Temporal Score - 6.4

 Exploitability          - Functional
 Remediation Level       - Official-Fix
 Report Confidence       - Confirmed

CSCso05337 - HA: Input queue wedged by ICMP packet

CVSS Base Score - 7.1

 Access Vector           - Network
 Access Complexity       - Medium
 Authentication          - None
 Confidentiality Impact  - None
 Integrity Impact        - None
 Availability Impact     - Complete

CVSS Temporal Score - 5.9

 Exploitability	         - Functional
 Remediation Level       - Official-Fix
 Report Confidence       - Confirmed

Impact
======

Successful exploitation of the vulnerability may result in an
interface to stop processing traffic, causing a DoS condition.

Software Versions and Fixes
===========================

When considering software upgrades, also consult 
http://www.cisco.com/go/psirt and any subsequent advisories to 
determine exposure and a complete upgrade solution.

In all cases, customers should exercise caution to be certain the
devices to be upgraded contain sufficient memory and that current
hardware and software configurations will continue to be supported
properly by the new release. If the information is not clear, contact
the Cisco Technical Assistance Center (TAC) or your contracted
maintenance provider for assistance.

Each row of the Cisco IOS software table (below) names a Cisco IOS
release train. If a given release train is vulnerable, then the
earliest possible releases that contain the fix (along with the
anticipated date of availability for each, if applicable) are listed
in the "First Fixed Release" column of the table. The "Recommended
Release" column indicates the releases which have fixes for all the
published vulnerabilities at the time of this Advisory. A device
running a release in the given train that is earlier than the release
in a specific column (less than the First Fixed Release) is known to
be vulnerable. Cisco recommends upgrading to a release equal to or
later than the release in the "Recommended Releases" column of the
table.

+-------------------------------------------------------------------+
|   Major    |          Availability of Repaired Releases           |
|  Release   |                                                      |
|------------+------------------------------------------------------|
| Affected   |                                      | Recommended   |
| 12.0-Based | First Fixed Release                  | Release       |
| Releases   |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.0 based releases                         |
|-------------------------------------------------------------------|
| Affected   |                                      | Recommended   |
| 12.1-Based | First Fixed Release                  | Release       |
| Releases   |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.1 based releases                         |
|-------------------------------------------------------------------|
| Affected   |                                      | Recommended   |
| 12.2-Based | First Fixed Release                  | Release       |
| Releases   |                                      |               |
|-------------------------------------------------------------------|
| There are no affected 12.2 based releases                         |
|-------------------------------------------------------------------|
| Affected   |                                      | Recommended   |
| 12.3-Based | First Fixed Release                  | Release       |
| Releases   |                                      |               |
|------------+--------------------------------------+---------------|
| 12.3       | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3B      | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3BC     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3BW     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3EU     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JEA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JEB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JEC    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JK     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JL     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3JX     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.3T      | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.3TPC    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3VA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XB     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XC     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XD     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XE     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XF     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XG     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XI     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XJ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XK     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XL     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XQ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XR     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XS     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XU     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XW     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XX     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XY     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3XZ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YD     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YF     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YG     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YH     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YI     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3YJ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            | Releases prior to 12.3(11)YK3 are    | 12.4(22)T1    |
|            | vulnerable, release 12.3(11)YK3 and  |               |
| 12.3YK     | later are not vulnerable; first      | 12.4(15)T9;   |
|            | fixed in 12.4T                       | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.3YM     | 12.3(14)YM13                         | 12.3(14)YM13  |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.3YQ     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.3YS     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.3YT     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.3YU     | Vulnerable; migrate to 12.4T         | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            | Releases prior to 12.3(14)YX10 are   |               |
| 12.3YX     | vulnerable, release 12.3(14)YX10 and | 12.3(14)YX14  |
|            | later are not vulnerable;            |               |
|------------+--------------------------------------+---------------|
| 12.3YZ     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.3ZA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| Affected   |                                      | Recommended   |
| 12.4-Based | First Fixed Release                  | Release       |
| Releases   |                                      |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(18e)     |
|            | 12.4(18e)                            |               |
| 12.4       |                                      | 12.4(23a);    |
|            | 12.4(23a); Available on 30-APR-2009  | Available on  |
|            |                                      | 30-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4JA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JDA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JK     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JL     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JMA    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JMB    | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4JX     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4MD     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4MR     | 12.4(19)MR                           | 12.4(19)MR2   |
|------------+--------------------------------------+---------------|
| 12.4SW     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            | 12.4(20)T                            | 12.4(22)T1    |
|            |                                      |               |
| 12.4T      | 12.4(15)T8                           | 12.4(15)T9;   |
|            |                                      | Available on  |
|            | 12.4(15)T9; Available on 29-APR-2009 | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XA     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            | 12.4(15)T8                           | 12.4(22)T1    |
|            |                                      |               |
| 12.4XB     | 12.4(20)T                            | 12.4(15)T9;   |
|            |                                      | Available on  |
|            | 12.4(15)T9; Available on 29-APR-2009 | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XC     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            | 12.4(4)XD12; Available on            | 12.4(4)XD12;  |
| 12.4XD     | 27-MAR-2009                          | Available on  |
|            |                                      | 27-MAR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XE     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XF     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4XG     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XJ     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4XK     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4XL     | 12.4(15)XL4                          | 12.4(15)XL4   |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XM     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4XN     | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.4XP     | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.4XQ     | 12.4(15)XQ2                          | 12.4(15)XQ2   |
|------------+--------------------------------------+---------------|
| 12.4XR     | 12.4(15)XR4                          | 12.4(22)T1    |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XT     | Vulnerable; first fixed in 12.4T     | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4XV     | Vulnerable; contact TAC              |               |
|------------+--------------------------------------+---------------|
| 12.4XW     | 12.4(11)XW10                         | 12.4(11)XW10  |
|------------+--------------------------------------+---------------|
|            |                                      | 12.4(22)T1    |
|            |                                      |               |
| 12.4XY     | 12.4(15)XY4                          | 12.4(15)T9;   |
|            |                                      | Available on  |
|            |                                      | 29-APR-2009   |
|------------+--------------------------------------+---------------|
| 12.4XZ     | 12.4(15)XZ1                          | 12.4(15)XZ2   |
|------------+--------------------------------------+---------------|
| 12.4YA     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4YB     | Not Vulnerable                       |               |
|------------+--------------------------------------+---------------|
| 12.4YD     | Not Vulnerable                       |               |
+-------------------------------------------------------------------+

Workarounds
===========

The following mitigation and identification methods have been
identified for these vulnerabilities:

Infrastructure Access Control Lists
+----------------------------------

Although it is often difficult to block traffic that transits a
network, it is possible to identify traffic that should never be
allowed to target infrastructure devices and block that traffic at
the border of networks. Infrastructure Access Control Lists (iACLs)
are a network security best practice and should be considered as a
long-term addition to good network security as well as a workaround
for these specific vulnerabilities. The iACL example below should be
included as part of the deployed infrastructure access-list which
will protect all devices with IP addresses in the infrastructure IP
address range:

IPv4 example:


    !--- Anti-spoofing entries are shown here.

    !--- Deny special-use address sources.
    !--- Refer to RFC 3330 for additional special use addresses.

    access-list 110 deny ip host 0.0.0.0 any
    access-list 110 deny ip 127.0.0.0 0.255.255.255 any
    access-list 110 deny ip 192.0.2.0 0.0.0.255 any
    access-list 110 deny ip 224.0.0.0 31.255.255.255 any

    !--- Filter RFC 1918 space.

    access-list 110 deny ip 10.0.0.0 0.255.255.255 any
    access-list 110 deny ip 172.16.0.0 0.15.255.255 any
    access-list 110 deny ip 192.168.0.0 0.0.255.255 any

    !--- Deny your space as source from entering your AS.
    !--- Deploy only at the AS edge.

    access-list 110 deny ip YOUR_CIDR_BLOCK any

    !--- Permit BGP.

    access-list 110 permit tcp host bgp_peer host router_ip eq bgp
    access-list 110 permit tcp host bgp_peer eq bgp host router_ip

    !--- Deny access to internal infrastructure addresses.

    access-list 110 deny ip any INTERNAL_INFRASTRUCTURE_ADDRESSES

    !--- Permit transit traffic.

    access-list 110 permit ip any any

IPv6 example:


    !--- Configure the access-list.

    ipv6 access-list iacl

    !--- Deny your space as source from entering your AS.
    !--- Deploy only at the AS edge.

    deny ipv6 YOUR_CIDR_BLOCK_IPV6 any

    !--- Permit multiprotocol BGP.

    permit tcp host bgp_peer_ipv6 host router_ipv6 eq bgp
    permit tcp host bgp_peer_ipv6 eq bgp host router_ipv6

    !--- Deny access to internal infrastructure addresses.

    deny ipv6 any INTERNAL_INFRASTRUCTURE_ADDRESSES_IPV6

    !--- Permit transit traffic.

    permit ipv6 any any

The white paper entitled "Protecting Your Core: Infrastructure
Protection Access Control Lists" presents guidelines and recommended
deployment techniques for infrastructure protection access lists.
This white paper can be obtained at the following link 
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml

Cisco IOS Embedded Event Manager
+-------------------------------

It is possible to detect blocked interface queues with a Cisco IOS
Embedded Event Manager (EEM) policy. EEM provides event detection and
reaction capabilities on a Cisco IOS device. EEM can alert
administrators of blocked interfaces with email, a syslog message, or
a Simple Network Management Protocol (SNMP) trap.

A sample EEM policy that uses syslog to alert administrators of
blocked interfaces is available at Cisco Beyond, an online community
dedicated to EEM. A sample script is available at the following link:

http://forums.cisco.com/eforum/servlet/EEM?page=eem&fn=script&scriptId=981

More information about EEM is available from Cisco.com at the
following link: 
http://www.cisco.com/en/US/products/ps6815/products_ios_protocol_group_home.html

Obtaining Fixed Software
========================

Cisco has released free software updates that address these
vulnerabilities. Prior to deploying software, customers should
consult their maintenance provider or check the software for feature
set compatibility and known issues specific to their environment.

Customers may only install and expect support for the feature sets
they have purchased. By installing, downloading, accessing or
otherwise using such software upgrades, customers agree to be bound
by the terms of Cisco's software license terms found at 
http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html,
or as otherwise set forth at Cisco.com Downloads at 
http://www.cisco.com/public/sw-center/sw-usingswc.shtml

Do not contact psirt at cisco.com or security-alert at cisco.com for
software upgrades.

Customers with Service Contracts
+-------------------------------

Customers with contracts should obtain upgraded software through
their regular update channels. For most customers, this means that
upgrades should be obtained through the Software Center on Cisco's
worldwide website at http://www.cisco.com

Customers using Third Party Support Organizations
+------------------------------------------------

Customers whose Cisco products are provided or maintained through
prior or existing agreements with third-party support organizations,
such as Cisco Partners, authorized resellers, or service providers
should contact that support organization for guidance and assistance
with the appropriate course of action in regards to this advisory.

The effectiveness of any workaround or fix is dependent on specific
customer situations, such as product mix, network topology, traffic
behavior, and organizational mission. Due to the variety of affected
products and releases, customers should consult with their service
provider or support organization to ensure any applied workaround or
fix is the most appropriate for use in the intended network before it
is deployed.

Customers without Service Contracts
+----------------------------------

Customers who purchase direct from Cisco but do not hold a Cisco
service contract, and customers who purchase through third-party
vendors but are unsuccessful in obtaining fixed software through
their point of sale should acquire upgrades by contacting the Cisco
Technical Assistance Center (TAC). TAC contacts are as follows.

  * +1 800 553 2447 (toll free from within North America)
  * +1 408 526 7209 (toll call from anywhere in the world)
  * e-mail: tac at cisco.com

Customers should have their product serial number available and be
prepared to give the URL of this notice as evidence of entitlement to
a free upgrade. Free upgrades for non-contract customers must be
requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html
for additional TAC contact information, including localized telephone
numbers, and instructions and e-mail addresses for use in various 
languages.

Exploitation and Public Announcements
=====================================

The Cisco PSIRT is not aware of any public announcements or malicious
use of the vulnerability described in this advisory.

This vulnerability was reported to Cisco by a customer.

Status of this Notice: FINAL
============================

THIS DOCUMENT IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY
KIND OF GUARANTEE OR WARRANTY, INCLUDING THE WARRANTIES OF
MERCHANTABILITY OR FITNESS FOR A PARTICULAR USE. YOUR USE OF THE
INFORMATION ON THE DOCUMENT OR MATERIALS LINKED FROM THE DOCUMENT IS
AT YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS
DOCUMENT AT ANY TIME.

A stand-alone copy or Paraphrase of the text of this document that
omits the distribution URL in the following section is an
uncontrolled copy, and may lack important information or contain
factual errors.

Distribution
============

This advisory is posted on Cisco's worldwide website at :

http://www.cisco.com/warp/public/707/cisco-sa-20090325-mobileip.shtml

In addition to worldwide web posting, a text version of this notice
is clear-signed with the Cisco PSIRT PGP key and is posted to the
following e-mail and Usenet news recipients.

  * cust-security-announce at cisco.com
  * first-bulletins at lists.first.org
  * bugtraq at securityfocus.com
  * vulnwatch at vulnwatch.org
  * cisco at spot.colorado.edu
  * cisco-nsp at puck.nether.net
  * full-disclosure at lists.grok.org.uk
  * comp.dcom.sys.cisco at newsgate.cisco.com

Future updates of this advisory, if any, will be placed on Cisco's
worldwide website, but may or may not be actively announced on
mailing lists or newsgroups. Users concerned about this problem are
encouraged to check the above URL for any updates.

Revision History
================

+---------------------------------------+
| Revision |             | Initial      |
| 1.0      | 2009-Mar-25 | public       |
|          |             | release      |
+---------------------------------------+

Cisco Security Procedures
=========================

Complete information on reporting security vulnerabilities in Cisco
products, obtaining assistance with security incidents, and
registering to receive security information from Cisco, is available
on Cisco's worldwide website at 
http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html
This includes instructions for press inquiries regarding Cisco 
security notices. All Cisco security advisories are available at 
http://www.cisco.com/go/psirt
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