[Full-disclosure] Cisco Security Advisory: IPv6 Routing Header Vulnerability



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Cisco Security Advisory: IPv6 Routing Header Vulnerability

Advisory ID: cisco-sa-20070124-IOS-IPv6

http://www.cisco.com/warp/public/707/cisco-sa-20070124-IOS-IPv6.shtml

Revision 1.0

For Public Release 2007 January 24 1600 UTC (GMT)

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

Summary
=======

Processing a specially crafted IPv6 Type 0 Routing header can crash a
device running Cisco IOS software. This vulnerability does not affect
IPv6 Type 2 Routing header which is used in mobile IPv6. IPv6 is not
enabled by default in Cisco IOS.

Cisco has made free software available to address this vulnerability
for affected customers.

There are workarounds available to mitigate the effects of the
vulnerability. The workaround depends on if Mobile IPv6 is used and
what version on Cisco IOS is being currently used.

This vulnerability was initially reported by a customer and further
trigger vector was discovered during developing the fix for this
vulnerability.

This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20070124-IOS-IPv6.shtml.

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

Devices running Cisco IOS and having IPv6 enabled on, at least, one of
their interface may be affected by this vulnerability.

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

To determine the software running on a Cisco product, log in to the
device and issue the "show version" command to display the system banner.
Cisco IOS software will identify itself as "Internetwork Operating
System Software" or simply "IOS". On the next line of output, the image
name will be displayed between parentheses, followed by "Version" and
the IOS release name. Other Cisco devices will not have the "show version"
command or will give different output.

The following example identifies a Cisco product running IOS release
12.4(9.10):

Cisco IOS Software, 7200 Software (C7200-JK9O3S-M), Version 12.4(9.10), INTERIM SOFTWARE
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2006 by Cisco Systems, Inc.
Compiled Mon 29-May-06 04:42 by prod_rel_team


Additional information about Cisco IOS release naming can be found at
http://www.cisco.com/warp/public/620/1.html.

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

No other Cisco products are known to be vulnerable to the issue
described in this Advisory. In particular Cisco IOS XR, Cisco PIX
Appliance and Cisco MDS 9000 Series devices are not affected by this
vulnerability.

Details
=======

This vulnerability can be triggered only when Cisco IOS processes
specifically crafted IPv6 Type 0 Routing headers, which are used for
source routing. Source routing is when an originator node explicitly
specifies the exact path that a packet must take to reach the
destination. Source routing is enabled by default on Cisco IOS if IPv6
is configured on the device. In order to trigger this vulnerability the
packet must be destined to any of the IPv6 addresses defined on the
device. The exact packet type is not relevant (e.g., TCP, ICMP, UDP) as
the vulnerability is on the IP layer. For this reason care must be
taken when implementing a workaround as this vulnerability can be
triggered by a spoofed packet.

IPv6 multicast packets can not be used to trigger this vulnerability.

In addition to Type 0 Routing headers, IPv6 also supports Type 2
Routing that is used in Mobile IPv6 implementation. Type 2 Routing
headers can not be used to trigger the vulnerability described in this
Advisory.

A router running vulnerable Cisco IOS software will process Type 0
Routing headers only if the destination address in the IPv6 packet is
one of the IPv6 addresses defined on any of the interfaces. The address
may be either a global (i.e., routable), loopback or link local
address. Link local addresses are not supposed to be routable and they
are valid only among directly connected devices.

A device may also be susceptible in scenarios where IPv6 packets are
tunneled over IPv4 networks provided that the IPv6 destination address
(after de-encapsulation) is one of the IPv6 addresses defined on the
device. This is independent of the exact encapsulation method used
(e.g., MPLS, GRE or IPv6-in-IPv4).

This vulnerability is documented in Cisco Bug IDs CSCsd40334
and CSCsd58381.

Vulnerability Scoring Details
+----------------------------

Cisco is providing scores for the vulnerabilities in this advisory
based on the Common Vulnerability Scoring System (CVSS).

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

Cisco PSIRT will set the bias in all cases to normal. Customers are
encouraged to apply the bias parameter when determining the
environmental impact of a particular vulnerability.

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

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.

Cisco Bug IDs:


CSCsd40334 - IPv6 packet can cause crash

CVSS Base Score: 10
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
Impact Bias: Normal

CVSS Temporal Score: 8.3
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed




CSCsd58381 - IPv6 routing header limitation

CVSS Base Score: 10
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: Complete
Integrity Impact: Complete
Availability Impact: Complete
Impact Bias: Normal

CVSS Temporal Score: 8.3
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed



Impact
======

Successful exploitation of the vulnerability listed in this Advisory
can corrupt some memory structures. In most cases this will cause the
affected device to crash and repeated exploitation could result in a
sustained DoS attack. However, due to memory corruption, there is a
potential to execute an arbitrary code. In the event of a successful
remote code execution, device integrity will have been completely
compromised.

Software Version 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) describes a release
train and the platforms or products for which it is intended. If a
given release train is vulnerable, then the earliest possible releases
that contain the fix (the "First Fixed Release") and the anticipated
date of availability for each are listed in the "Rebuild" and
"Maintenance" columns. 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. The release should be
upgraded at least to the indicated release or a later version (greater
than or equal to the First Fixed Release label).

For more information on the terms "Rebuild" and "Maintenance," consult
the following URL: http://www.cisco.com/warp/public/620/1.html.

Please note: There are 3 IOS security advisories and one field notice
being published on Jan 24th, 2007. Each advisory only lists the
releases which fix the issue described in the advisory. A combined
software table is available at
http://www.cisco.com/warp/public/707/cisco-sa-20070124-bundle.shtml
and can be used to choose a software release which fixes all security
vulnerabilities published as of January 24th, 2007. The advisories and
field notice published on January 24 are listed here.

* http://www.cisco.com/warp/public/707/cisco-air-20070124-IOS-ipv6.shtml
* http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-tcp.shtml
* http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-ip-option.shtml
* http://www.cisco.com/warp/public/770/fn62613.shtml

Requests for software rebuilds to include the change for Daylight
Savings Time (DST) that will be implemented in March 2007 should be
directed through the Technical Assistance Center (TAC) and this
advisory should be used as reference.

+-----------------------------------------------------------------------------+
| Major Release | Availability of Repaired Releases |
|------------------------------+----------------------------------------------|
| Affected 12.0-Based Release | Rebuild | Maintenance |
|------------------------------+----------------------------------------------|
| 12.0 | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0DA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0DB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0DC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0S | 12.0(32)S3 | |
|------------------------------+----------------------------------------------|
| 12.0SC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0SL | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0SP | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0ST | Vulnerable; migrate to 12.0(32)S3 or later |
|------------------------------+----------------------------------------------|
| 12.0SX | Vulnerable for only 12.0(30)SX; contact TAC |
|------------------------------+----------------------------------------------|
| 12.0SY | | 12.0(32)SY |
|------------------------------+----------------------------------------------|
| 12.0SZ | Vulnerable; migrate to 12.0(32)S3 or later |
|------------------------------+----------------------------------------------|
| 12.0T | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0W | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0WC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0WT | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XD | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XE | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XF | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XG | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XH | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XI | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XJ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XK | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XL | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XM | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XN | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XQ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XR | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XS | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XV | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.0XW | Not vulnerable |
|------------------------------+----------------------------------------------|
| Affected 12.1-Based Release | Rebuild | Maintenance |
|------------------------------+----------------------------------------------|
| 12.1 | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1AA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1AX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1AY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1AZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1CX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1DA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1DB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1DC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1E | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EO | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EU | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EV | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EW | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1EZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1T | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XD | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XE | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XF | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XG | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XH | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XI | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XJ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XL | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XM | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XP | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XQ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XR | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XS | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XT | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XU | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.1XV | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.1XW | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1XZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YB | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.1YC | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.1YD | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.1YE | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YF | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YH | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YI | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.1YJ | Not vulnerable |
|------------------------------+----------------------------------------------|
| Affected 12.2-Based Release | Rebuild | Maintenance |
|------------------------------+----------------------------------------------|
| 12.2 | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2B | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2BC | Vulnerable; migrate to 12.3(17b)BC3 or later |
|------------------------------+----------------------------------------------|
| 12.2BW | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2BY | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2BZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2CX | Vulnerable; migrate to 12.3(17b)BC3 or later |
|------------------------------+----------------------------------------------|
| 12.2CY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2CZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2DA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2DD | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2DX | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2EU | Vulnerable; migrate to 12.2(25)EWA6 or later |
|------------------------------+----------------------------------------------|
| 12.2EW | Vulnerable; migrate to 12.2(25)EWA6 or later |
|------------------------------+----------------------------------------------|
| 12.2EWA | 12.2(25)EWA6 | |
|------------------------------+----------------------------------------------|
| 12.2EX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2EY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2EZ | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------------------------+----------------------------------------------|
| 12.2FX | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2FY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2FZ | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2IXA | Vulnerable; migrate to 12.2(18)IXB or later |
|------------------------------+----------------------------------------------|
| 12.2IXB | All 12.2IXB releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2IXC | All 12.2IXC releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2JA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2JK | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2MB | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2MC | 12.2(15)MC2h | |
|------------------------------+---------------------+------------------------|
| 12.2S | 12.2(25)S11 | 12.2(30)S |
|------------------------------+---------------------+------------------------|
| 12.2SB | 12.2(28)SB2 | 12.2(31)SB |
|------------------------------+---------------------+------------------------|
| 12.2SBC | 12.2(27)SBC4 | |
|------------------------------+----------------------------------------------|
| 12.2SEA | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------------------------+----------------------------------------------|
| 12.2SEB | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------------------------+----------------------------------------------|
| 12.2SEC | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------------------------+----------------------------------------------|
| 12.2SED | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------------------------+----------------------------------------------|
| 12.2SEE | 12.2(25)SEE1 | |
|------------------------------+---------------------+------------------------|
| 12.2SEF | 12.2(25)SEF1 | |
|------------------------------+----------------------------------------------|
| 12.2SEG | All 12.2SEG releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2SG | 12.2(25)SG1 | 12.2(31)SG |
|------------------------------+----------------------------------------------|
| 12.2SGA | All 12.2SGA releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2SO | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2SRA | All 12.2SRA releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2SRB | All 12.2SRB releases are fixed |
|------------------------------+----------------------------------------------|
| 12.2SU | Vulnerable; migrate to 12.3(14)T7 or later |
|------------------------------+----------------------------------------------|
| 12.2SV | 12.2(25)SV3 | 12.2(26)SV |
|------------------------------+---------------------+------------------------|
| 12.2SW | 12.2(25)SW7 | |
|------------------------------+----------------------------------------------|
| 12.2SX | Vulnerable; migrate to 12.2(18)SXD7a or |
| | later |
|------------------------------+----------------------------------------------|
| 12.2SXA | Vulnerable; migrate to 12.2(18)SXD7a or |
| | later |
|------------------------------+----------------------------------------------|
| 12.2SXB | Vulnerable; migrate to 12.2(18)SXD7a or |
| | later |
|------------------------------+----------------------------------------------|
| 12.2SXD | 12.2(18)SXD7a | |
|------------------------------+---------------------+------------------------|
| 12.2SXE | 12.2(18)SXE6 | |
|------------------------------+---------------------+------------------------|
| 12.2SXF | 12.2(18)SXF5 | |
|------------------------------+----------------------------------------------|
| 12.2SY | Vulnerable; migrate to 12.2(18)SXD7a or |
| | later |
|------------------------------+----------------------------------------------|
| 12.2SZ | Vulnerable; migrate to 12.2(25)S11 or later |
|------------------------------+----------------------------------------------|
| 12.2T | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2TPC | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.2XA | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XB | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XC | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2XD | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XE | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2XF | Vulnerable; migrate to 12.3(17b)BC3 or later |
|------------------------------+----------------------------------------------|
| 12.2XG | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XH | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XI | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XJ | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XK | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XL | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XM | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XN | | 12.2(31)XN |
|------------------------------+----------------------------------------------|
| 12.2XQ | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XR | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2XS | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XT | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XU | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XV | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2XW | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YA | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YB | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2YD | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.2YE | Vulnerable; migrate to 12.2(25)S11 or later |
|------------------------------+----------------------------------------------|
| 12.2YF | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YG | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2YH | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YJ | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YK | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2YL | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YM | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YN | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YO | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2YP | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2YQ | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YR | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YT | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2YU | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YV | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YW | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YX | Vulnerable; migrate to 12.3(14)T7 or later |
|------------------------------+----------------------------------------------|
| 12.2YY | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2YZ | Vulnerable; migrate to 12.2(25)S11 or later |
|------------------------------+----------------------------------------------|
| 12.2ZA | Vulnerable; migrate to 12.2(18)SXD7a or |
| | later |
|------------------------------+----------------------------------------------|
| 12.2ZB | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2ZC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2ZD | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.2ZE | Vulnerable; migrate to 12.3(18) or later |
|------------------------------+----------------------------------------------|
| 12.2ZF | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2ZG | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.2ZH | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.2ZJ | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2ZL | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.2ZN | Vulnerable; migrate to 12.3(4)T13 or later |
|------------------------------+----------------------------------------------|
| 12.2ZP | Not vulnerable |
|------------------------------+----------------------------------------------|
| Affected 12.3-Based Release | Rebuild | Maintenance |
|------------------------------+---------------------+------------------------|
| 12.3 | 12.3(17b) | 12.3(18) |
|------------------------------+----------------------------------------------|
| 12.3B | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3BC | 12.3(17b)BC3 | |
|------------------------------+----------------------------------------------|
| 12.3BW | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3JA | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.3JEA | All 12.3JEA releases are fixed |
|------------------------------+----------------------------------------------|
| 12.3JEB | All 12.3JEA releases are fixed |
|------------------------------+----------------------------------------------|
| 12.3JK | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.3JX | Not vulnerable |
|------------------------------+----------------------------------------------|
| | 12.3(4)T13 | |
| |---------------------+------------------------|
| 12.3T | 12.3(11)T10 | |
| |---------------------+------------------------|
| | 12.3(14)T7 | |
|------------------------------+----------------------------------------------|
| 12.3TPC | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.3XA | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3XB | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3XC | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3XD | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3XE | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3XF | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3XG | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3XH | Vulnerable; migrate to 12.3(11)T10 or later |
|------------------------------+----------------------------------------------|
| 12.3XI | 12.3(7)XI8a | 12.3(7)XI9 |
|------------------------------+----------------------------------------------|
| 12.3XJ | Vulnerable; migrate to 12.3(14)YX2 or later |
|------------------------------+----------------------------------------------|
| 12.3XK | Vulnerable; migrate to 12.3(14)T7 or later |
|------------------------------+----------------------------------------------|
| 12.3XQ | Vulnerable; migrate to 12.4(8) or later |
|------------------------------+----------------------------------------------|
| 12.3XR | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3XS | Vulnerable; migrate to 12.4(8) or later |
|------------------------------+----------------------------------------------|
| 12.3XU | Vulnerable; migrate to 12.4(2)T4 or later |
|------------------------------+----------------------------------------------|
| 12.3XW | Vulnerable; migrate to 12.3(14)YX2 or later |
|------------------------------+----------------------------------------------|
| 12.3XX | Vulnerable; migrate to 12.4(8) or later |
|------------------------------+----------------------------------------------|
| 12.3XY | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.3YA | Vulnerable; contact TAC |
|------------------------------+----------------------------------------------|
| 12.3YD | Vulnerable; migrate to 12.4(2)T4 or later |
|------------------------------+----------------------------------------------|
| 12.3YF | Vulnerable; migrate to 12.3(14)YX2 or later |
|------------------------------+----------------------------------------------|
| 12.3YG | Vulnerable; migrate to 12.4(2)T4 or later |
|------------------------------+----------------------------------------------|
| 12.3YH | Vulnerable; migrate to 12.4(2)T4 or later |
|------------------------------+----------------------------------------------|
| 12.3YI | Vulnerable; migrate to 12.4(2)T4 or later |
|------------------------------+----------------------------------------------|
| 12.3YJ | Vulnerable; migrate to 12.4(6)T1 or later |
|------------------------------+----------------------------------------------|
| 12.3YK | Vulnerable; migrate to 12.4(4)T2 or later |
|------------------------------+----------------------------------------------|
| 12.3YM | 12.3(14)YM8 | |
|------------------------------+----------------------------------------------|
| 12.3YQ | Vulnerable; migrate to 12.4(6)T1 or later |
|------------------------------+----------------------------------------------|
| 12.3YS | Vulnerable; migrate to 12.4(4)T2 or later |
|------------------------------+----------------------------------------------|
| 12.3YT | Vulnerable; migrate to 12.4(4)T2 or later |
|------------------------------+----------------------------------------------|
| 12.3YU | Vulnerable; migrate to 12.4(2)XB2 or later |
|------------------------------+----------------------------------------------|
| 12.3YX | 12.3(14)YX2 | |
|------------------------------+---------------------+------------------------|
| 12.3YZ | 12.3(11)YZ1 | |
|------------------------------+---------------------+------------------------|
| Affected 12.4-Based Release | Rebuild | Maintenance |
|------------------------------+---------------------+------------------------|
| | 12.4(3d) | |
| |---------------------+------------------------|
| 12.4 | 12.4(5b) | |
| |---------------------+------------------------|
| | 12.4(7a) | 12.4(8) |
|------------------------------+----------------------------------------------|
| 12.4MR | Not vulnerable |
|------------------------------+----------------------------------------------|
| 12.4SW | All 12.4SW releases are fixed |
|------------------------------+----------------------------------------------|
| | 12.4(2)T4 | |
| |---------------------+------------------------|
| 12.4T | 12.4(4)T2 | |
| |---------------------+------------------------|
| | 12.4(6)T1 | 12.4(9)T |
|------------------------------+----------------------------------------------|
| 12.4XA | Vulnerable; migrate to 12.4(6)T1 or later |
|------------------------------+----------------------------------------------|
| 12.4XB | 12.4(2)XB2 | |
|------------------------------+---------------------+------------------------|
| 12.4XC | 12.4(4)XC5 | |
|------------------------------+---------------------+------------------------|
| 12.4XD | 12.4(4)XD2 | |
|------------------------------+----------------------------------------------|
| 12.4XE | All 12.4XE releases are fixed |
|------------------------------+----------------------------------------------|
| 12.4XG | All 12.4XG releases are fixed |
|------------------------------+----------------------------------------------|
| 12.4XJ | All 12.4XJ releases are fixed |
|------------------------------+----------------------------------------------|
| 12.4XP | All 12.4XP releases are fixed |
|------------------------------+----------------------------------------------|
| 12.4XT | All 12.4XT releases are fixed |
+-----------------------------------------------------------------------------+

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

The workaround consists of filtering packets that contain Type 0
Routing header(s). Special attention must be paid not to filter packets
with Type 2 Routing headers as that would break Mobile IPv6 deployment.
Depending on what Cisco IOS software release is used and if Mobile IPv6
is deployed or not we have the following workarounds. As any packet
type can be used to trigger this vulnerability the care must be taken
when implementing a workaround to account for a spoofed packet.

Additional mitigations that can be deployed on Cisco devices within the
network are available in the Cisco Applied Intelligence companion
document for this advisory:
http://www.cisco.com/warp/public/707/cisco-air-20070124-IOS-IPv6.shtml

Mobile IPv6 is not deployed
+--------------------------

For IOS releases before 12.3(4)T the workaround is to use ACLs to
filter all packets that contain Routing headers. This method can not
distinguish between Type 0 and Type 2 Routing headers so it is not
suitable if Mobile IPv6 is deployed.

The following example shows how to configure such ACLs.

Router(config)#ipv6 access-list deny-sourcerouted
Router(config-ipv6-acl)#deny ipv6 any <myaddress1> routing
Router(config-ipv6-acl)#deny ipv6 any <myaddress2> routing
Router(config-ipv6-acl)#permit ipv6 any any
Router(config-ipv6-acl)#exit
Router(config)#interface Ethernet0
Router(config-if)#ipv6 traffic-filter deny-sourcerouted in


In this example <myaddressX> is an IPv6 address. One example of such
address is 2600:dead:beef:cafe:0:1:0:1111. The ACL must be applied to
all interfaces and all IPv6 addresses that are configured. If an
interface has more than one IPv6 address configured then all addresses
must be covered by the ACLs. This also includes all loopback and "link
local" addresses for each interface.

The alternative of enumerating all IPv6 addresses is to use statement
"deny ipv6 any any routing". While that simplifies the resulting ACL it
will also filter all transit IPv6 traffic with Routing headers 0 and 2.
The example where all configured IPv6 addresses are enumerated will not
affect transit traffic. This comment is applicable to all other
examples in this Advisory.

Starting from the IOS release 12.2(15)T a new command "ipv6 source-route"
was introduced. If applied, it will block any IPv6 packet with any IPv6
routing headers (both types 0 and 2). The configuration is given in the
following example.

Router(config)#no ipv6 source-route


This is a global command and it applies to all interfaces. The command
is applicable on all defined IPv6 addresses, including the link local
and loopback address, and on all interfaces.

Mobile IPv6 is deployed
+----------------------

There is no workaround if you are running a Cisco IOS release prior to
12.4(2)T. In IOS 12.4(2)T a new keyword "routing-type" is added to IPv6
ACLs. It can be used to selectively permit or deny specific routing
types.

Router(config)#ipv6 access-list deny-sourcerouted
Router(config-ipv6-acl)#deny ipv6 any <myaddress1> routing-type 0
Router(config-ipv6-acl)#permit ipv6 any any
Router(config)#interface Ethernet0
Router(config-if)#ipv6 source-route
Router(config-if)#ipv6 traffic-filter deny-sourcerouted in


The filter must be applied to all interfaces that have IPv6 configured.

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

Cisco will make free software available to address this vulnerability
for affected customers. This advisory will be updated as fixed software
becomes available. 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/public/sw-license-agreement.html, or as otherwise
set forth at Cisco.com Downloads at
http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact either "psirt@xxxxxxxxx" or "security-alert@xxxxxxxxx"
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 agreement 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 who do not hold a Cisco
service contract and customers who purchase through third-party vendors
but are unsuccessful at obtaining fixed software through their point of
sale should get their 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@xxxxxxxxx

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

Refer to http://www.cisco.com/warp/public/687/Directory/DirTAC.shtml
for additional TAC contact information, including special 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 initially reported to Cisco by Arnaud Ebalard
from EADS Corporate Research Center. An additional vector to trigger it
was discovered internally while fixing the vulnerability.

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-20070124-IOS-IPv6.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@xxxxxxxxx
* first-teams@xxxxxxxxx
* bugtraq@xxxxxxxxxxxxxxxxx
* vulnwatch@xxxxxxxxxxxxx
* cisco@xxxxxxxxxxxxxxxxx
* cisco@xxxxxxxxxxxxxxxxx
* cisco-nsp@xxxxxxxxxxxxxxx
* full-disclosure@xxxxxxxxxxxxxxxxx
* comp.dcom.sys.cisco@xxxxxxxxxxxxxxxxxx

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
================

+----------------------------------------+
| 1.0 | 2007-January-24 | Initial 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.

- -----------------------------------------------------------------------
All contents are Copyright 1992-2007 Cisco Systems, Inc. All rights
reserved.
- -----------------------------------------------------------------------

Updated: Jan 24, 2007 Document ID: 72372

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