Cisco Security Advisory: Multiple Crafted IPv6 Packets Cause Reload
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Cisco Security Advisory: Multiple Crafted IPv6 Packets Cause Reload
Revision 1.0
For Public Release 2005 January 26 1600 UTC (GMT)
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Contents
Summary
Affected Products
Details
Impact
Software Versions and Fixes
Obtaining Fixed Software
Workarounds
Exploitation and Public Announcements
Status of This Notice: FINAL
Distribution
Revision History
Cisco Security Procedures
- --------------------------------------------------------------------------
Summary
=======
Cisco Internetwork Operating System (IOS) Software is vulnerable to a Denial
of Service (DoS) attack from crafted IPv6 packets when the device has been
configured to process IPv6 traffic. This vulnerability requires multiple
crafted packets to be sent to the device which may result in a reload upon
successful exploitation.
Cisco has made free software available to address this vulnerability.
There are workarounds available to mitigate the effects.
This issue is tracked by CERT/CC VU#472582
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20050126-ipv6.shtml.
Affected Products
=================
Vulnerable Products
Only the Cisco devices running IOS and configured for IPv6 are affected. A
router will display all IPv6 enabled interfaces with the show ipv6 interface
command.
An empty output or an error message will be displayed if IPv6 is disabled or
unsupported on the system. In this case the system is not vulnerable.
Sample output of show ipv6 interface command is shown below for a system
configured for IPv6.
Router#show ipv6 interface
Serial1/0 is up, line protocol is up
IPv6 is enabled, link-local address is FE80::A8BB:CCFF:FE00:D200
Global unicast address(es):
2001:1:33::3, subnet is 2001:1:33::/64 [TENTATIVE]
Joined group address(es):
FF02::1
FF02::1:FF00:3
FF02::1:FF00:D200
MTU is 1500 bytes
ICMP error messages limited to one every 100 milliseconds
ICMP redirects are enabled
ND DAD is enabled, number of DAD attempts: 1
ND reachable time is 30000 milliseconds
Router#
A router that has IPv6 enabled on a physical or logical interface is vulnerable
to this issue even if ipv6 unicast-routing is globally disabled. The show ipv6
interface command can be used to determine whether IPv6 is enabled on any
interface.
Products Confirmed Not Vulnerable
* Products that are not running Cisco IOS are not affected.
* Products running any version of Cisco IOS that do not have IPv6 configured
interfaces are not vulnerable.
No other Cisco products are currently known to be affected by these
vulnerabilities.
Details
=======
IPv6 is the "Internet Protocol Version 6", designed by the Internet Engineering
Task Force (IETF) to replace the current version Internet Protocol, IP Version
4 (IPv4).
A vulnerability exists in the processing of IPv6 packets that can be exploited
to cause the reload of a system. Crafted packets received on logical interfaces
(that is, tunnels including 6to4 tunnels) as well as physical interfaces can
trigger this vulnerability.
Multiple crafted IPv6 packets need to be sent to exploit this vulnerability.
Such crafted packets can be sent remotely.
This issue is documented in Cisco bug ID CSCed40933 ( registered customers
only) .
Impact
======
Successful exploitation of this vulnerability results in a reload of the
device. Repeated exploitation could result in a sustained DoS attack.
Software Versions and Fixes
===========================
+-----------------------------------------------------+
| Major | Availability of Repaired Releases |
| Release | |
|------------+----------------------------------------|
| Affected | | | | |
| 12.0-Based | Rebuild | Interim | Maintenance | |
| Release | | | | |
|------------+-------------+---------+-------------+--|
| | 12.0(23)S | | | |
| | and before | | | |
| | are not | | | |
| | vulnerable. | | | |
| |-------------+---------+-------------+--|
| | 12.0(24)S6 | | | |
|12.0S |-------------+---------+-------------+--|
| | 12.0(25)S3 | | | |
| |-------------+---------+-------------+--|
| | 12.0(26)S2 | | | |
| |-------------+---------+-------------+--|
| | 12.0(27)S1 | | | |
| |-------------+---------+-------------+--|
| | | | 12.0(28)S | |
|------------+-------------+---------+-------------+--|
| 12.0SX | 12.0(25)SX8 | | | |
|------------+-------------------------------------+--|
| 12.0SZ | 12.0(27)SZ | |
|------------+-------------------------------------+--|
| Affected | | | | |
| 12.2-Based | Rebuild | Interim | Maintenance | |
| Release | | | | |
|------------+-------------------------------------+--|
| | 12.2(2)B - 12.2(4)B7 Migrate to | |
| | 12.2(13)T14 or later | |
|12.2B |-------------------------------------+--|
| | 12.2(4)B8 AND FWD Migrate to 12.3 | |
| | (7)T or later | |
|------------+-------------------------------------+--|
| 12.2BC | Migrate to 12.3(9a)BC | |
|------------+-------------------------------------+--|
| 12.2BX | Migrate to 12.3(7)XI1 | |
|------------+-------------------------------------+--|
| 12.2BZ | Migrate to 12.3(7)XI1 | |
|------------+-------------------------------------+--|
| 12.2CX | No plan. | |
|------------+-------------------------------------+--|
| 12.2CZ | No plan. | |
|------------+-------------------------------------+--|
| 12.2EW | 12.2(18)EW1 | |
|------------+-------------------------------------+--|
| 12.2EWA | | | 12.2(20)EWA | |
|------------+-------------+---------+-------------+--|
| 12.2JK | 12.2(15)JK2 | | | |
|------------+-------------------------------------+--|
| 12.2MC | Migrate to 12.3(11)T | |
|------------+-------------------------------------+--|
| | 12.2(14)S9 | | | |
| |-------------+---------+-------------+--|
| | 12.2(18)S5 | | | |
| |-------------+---------+-------------+--|
| 12.2S | 12.2(20)S3 | | | |
| |-------------+---------+-------------+--|
| | 12.2(22)S1 | | | |
| |-------------+---------+-------------+--|
| | | | 12.2(25)S | |
|------------+-------------------------------------+--|
| 12.2SE | 12.2(25)SE | |
|------------+-------------------------------------+--|
| 12.2SU | 12.2(14)SU1 | | | |
|------------+-------------------------------------+--|
| 12.2SV | 12.2(23)SV | |
|------------+-------------------------------------+--|
| 12.2SW | 12.2(23)SW | |
|------------+-------------------------------------+--|
| 12.2SX | Migrate to 12.2(17d)SXB2 or later | |
|------------+-------------------------------------+--|
| 12.2SXA | Migrate to 12.2(17d)SXB1 or later | |
|------------+-------------------------------------+--|
| 12.2SXB | 12.2(17d) | | | |
| | SXB1 | | | |
|------------+-------------+---------+-------------+--|
| 12.2SXD | | | 12.2(18)SXD | |
|------------+-------------------------------------+--|
| 12.2SY | Migrate to 12.2(17d)SXB2 or later | |
|------------+-------------------------------------+--|
| 12.2SZ | Migrate to 12.2(20)S4 | |
|------------+-------------------------------------+--|
| | 12.2(13)T14 | | | |
|12.2T |-------------+---------+-------------+--|
| | 12.2(15)T12 | | | |
|------------+-------------------------------------+--|
| 12.2YT | Migrate to 12.2(15)T13 or later | |
|------------+-------------------------------------+--|
| 12.2YU | Migrate to 12.3(4)T6 or later | |
|------------+-------------------------------------+--|
| 12.2YV | Migrate to 12.3(4)T6 or later | |
|------------+-------------------------------------+--|
| 12.2YZ | Migrate to 12.2(20)S4 or later | |
|------------+-------------------------------------+--|
| 12.2ZC | Migrate to 12.3T or later | |
|------------+-------------------------------------+--|
| 12.2ZD | Migrate to 12.3 or later | |
|------------+-------------------------------------+--|
| 12.2ZE | Migrate to 12.3 or later | |
|------------+-------------------------------------+--|
| 12.2ZF | Migrate to 12.3(4)T6 or later | |
|------------+-------------------------------------+--|
| 12.2ZG | Migrate to 12.3(4)T6 or later | |
|------------+-------------------------------------+--|
| 12.2ZH | Migrate to 12.3(4)T6 or later | |
|------------+-------------------------------------+--|
| 12.2ZI | Migrate to 12.2(18)S or later | |
|------------+-------------------------------------+--|
| 12.2ZJ | Migrate to 12.3 or later | |
|------------+-------------------------------------+--|
| 12.2ZL | Migrate to 12.3(7)T or later | |
|------------+-------------------------------------+--|
| 12.2ZN | Migrate to 12.3(2)T6 or later | |
|------------+-------------------------------------+--|
| 12.2ZO | Migrate to 12.2(15)T12 or later | |
|------------+-------------------------------------+--|
| 12.2ZP | Migrate to 12.3(8)XY or later | |
|------------+-------------------------------------+--|
| Affected | | | | |
| 12.3-Based | Rebuild | Interim | Maintenance | |
| Release | | | | |
|------------+-------------+---------+-------------+--|
| | 12.3(3f) | | | |
| |-------------+---------+-------------+--|
| | 12.3(5c) | | | |
|12.3 |-------------+---------+-------------+--|
| | 12.3(6a) | | | |
| |-------------+---------+-------------+--|
| | | | 12.3(9) | |
|------------+-------------+---------+-------------+--|
| 12.3BC | | | 12.3(9a)BC | |
|------------+-------------+---------+-------------+--|
| 12.3B | 12.3(5a)B2 | | | |
|------------+-------------------------------------+--|
| 12.3BW | Migrate to 12.3(5a)B2 or later | |
|------------+-------------------------------------+--|
| 12.3JA | | | 12.3(2)JA | |
|------------+-------------+---------+-------------+--|
| | 12.3(2)T6 | | | |
| |-------------+---------+-------------+--|
| 12.3T | 12.3(4)T6 | | | |
| |-------------+---------+-------------+--|
| | | | 12.3(7)T | |
|------------+-------------------------------------+--|
| 12.3XA | Migrate to 12.3(7)T or later | |
|------------+-------------------------------------+--|
| 12.3XB | Migrate to 12.3(8)T or later | |
|------------+-------------------------------------+--|
| 12.3XC | Migrate 12.3(2)XC3 or later | |
|------------+-------------------------------------+--|
| 12.3XD | 12.3(4)XD4 | | | |
|------------+-------------------------------------+--|
| 12.3XE | 12.3(2)XE1 | |
|------------+-------------------------------------+--|
| 12.3XF | Migrate to 12.3(11)T or later | |
|------------+-------------------------------------+--|
| 12.3XG | 12.3(4)XG2 | | | |
|------------+-------------------------------------+--|
| 12.3XH | Migrate to 12.3(11)T or later | |
|------------+-------------------------------------+--|
| 12.3XI | | | 12.3(7)XI | |
|------------+-------------------------------------+--|
| 12.3XJ | 12.3(7)XJ | |
|------------+-------------------------------------+--|
| 12.3XK | 12.3(4)XK1 | | | |
|------------+-------------+---------+-------------+--|
| 12.3XL | | | 12.3(7)XL | |
|------------+-------------+---------+-------------+--|
| 12.3XM | | | 12.3(7)XM | |
|------------+-------------------------------------+--|
| 12.3XN | Migrate to 12.3(14)T or later | |
|------------+-------------------------------------+--|
| 12.3XQ | 12.3(4)XQ | |
|------------+-------------------------------------+--|
| 12.3XR | | | 12.3(7)XR | |
|------------+-------------------------------------+--|
| 12.3XS | 12.3(7)XS | |
|------------+-------------------------------------+--|
| 12.3XT | 12.3(2)XT | |
|------------+-------------------------------------+--|
| 12.3XU | 12.3(8)XU | |
|------------+-------------------------------------+--|
| 12.3XX | | | 12.3(8)XX | |
|------------+-------------+---------+-------------+--|
| 12.3XW | | | 12.3(8)XW | |
|------------+-------------+---------+-------------+--|
| 12.3XY | | | 12.3(8)XY | |
|------------+-------------+---------+-------------+--|
| 12.3XZ | | | 12.3(2)XZ | |
|------------+-------------+---------+-------------+--|
| 12.3YA | | | 12.3(8)YA | |
|------------+-------------+---------+-------------+--|
| 12.3YD | | | 12.3(8)YD | |
|------------+-------------+---------+-------------+--|
| 12.3YE | | | 12.3(4)YE | |
|------------+-------------+---------+-------------+--|
| 12.3YF | | | 12.3(11)YF | |
|------------+-------------+---------+-------------+--|
| 12.3YG | | | 12.3(8)YG | |
|------------+-------------+---------+-------------+--|
| 12.3YH | | | 12.3(8)YH | |
+-----------------------------------------------------+
When considering software upgrades, please also consult http://www.cisco.com/en
/US/products/products_security_advisories_listing.html 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) for assistance.
Obtaining Fixed Software
========================
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 assistance with the upgrade, which should be free of
charge.
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
Please 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.
Please do not contact either "psirt@xxxxxxxxx" or "security-alert@xxxxxxxxx"
for software upgrades.
See 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.
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.
Workarounds
===========
The effectiveness of any workaround 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 is the most appropriate for use in the intended
network before it is deployed.
Although it is often difficult to block traffic transiting your network, it is
possible to identify traffic which should never be allowed to target your
infrastructure devices and block that traffic at the border of your network.
Infrastructure access control lists (ACLs) are considered a network security
best practice and should be considered as a long-term addition to good network
security as well as a workaround for this specific vulnerability. The white
paper entitled "Protecting Your Core: Infrastructure Protection Access Control
Lists", available at http://www.cisco.com/warp/public/707/iacl.html, presents
guidelines and recommended deployment techniques for infrastructure protection
ACLs. Exceptions would include any devices which have a legitimate reason to
access your infrastructure (for example, BGP peers, DNS servers, and so on).
All other traffic must be able to traverse your network without terminating on
any of your devices.
Exploitation and Public Announcements
=====================================
The Cisco PSIRT is not aware of any public announcements or malicious use of
the vulnerability described in this advisory.
Status of This Notice: FINAL
============================
THIS ADVISORY IS PROVIDED ON AN "AS IS" BASIS AND DOES NOT IMPLY ANY KIND OF
GUARANTEE OR WARRANTY, INCLUDING THE WARRANTY OF MERCHANTABILITY. YOUR USE OF
THE INFORMATION ON THE ADVISORY OR MATERIALS LINKED FROM THE ADVISORY IS AT
YOUR OWN RISK. CISCO RESERVES THE RIGHT TO CHANGE OR UPDATE THIS NOTICE AT ANY
TIME.
A stand-alone copy or paraphrase of the text of this security advisory 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 will be posted on Cisco's worldwide website at http://
www.cisco.com/warp/public/707/cisco-sa-20050126-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 (includes CERT/CC)
* bugtraq@xxxxxxxxxxxxxxxxx
* vulnwatch@xxxxxxxxxxxxx
* cisco@xxxxxxxxxxxxxxxxx
* cisco-nsp@xxxxxxxxxxxxxxx
* full-disclosure@xxxxxxxxxxxxxxxx
* comp.dcom.sys.cisco@xxxxxxxxxxxxxxxxxx
* Various internal Cisco mailing lists
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 | 2005-January-26 | Initial public |
| 1.0 | | 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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