From: Cisco Systems Product Security Incident Response Team <psirt@cisco.com.>
To: [email protected]Subject: Cisco Security Advisory: Crafted TCP Packet Can Cause Denial of Service
Date: Wed, 24 Jan 2007 16:12:00 -0000
Message-id: <20070124.tcp@psirt.cisco.com.>
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Hash: SHA1
Cisco Security Advisory: Crafted TCP Packet Can Cause Denial of
Service
Advisory ID: cisco-sa-20070124-crafted-tcp
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-tcp.shtml
Revision 1.0
For Public Release 2007 January 24 1600 UTC (GMT)
- ---------------------------------------------------------------------
Summary
=======
The Cisco IOS Transmission Control Protocol (TCP) listener in certain
versions of Cisco IOS software is vulnerable to a
remotely-exploitable memory leak that may lead to a denial of service
condition.
This vulnerability only applies to traffic destined to the Cisco IOS
device. Traffic transiting the Cisco IOS device will not trigger this
vulnerability.
Cisco has made free software available to address this vulnerability
for affected customers.
This issue is documented as Cisco bug ID CSCek37177.
There are workarounds available to mitigate the effects of the
vulnerability.
This advisory is posted at
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-tcp.shtml
Affected Products
=================
Vulnerable Products
+------------------
This issue affects all Cisco devices running Cisco IOS software. To
be affected, devices must be configured to process Internet Protocol
version 4 (IPv4) packets and receive TCP packets. Devices which run
only Internet Protocol version 6 (IPv6) are not affected.
This vulnerability is present in all unfixed versions of Cisco IOS
software, including versions 9.x, 10.x, 11.x and 12.x.
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 Cisco IOS
release 12.2(14)S16 with an installed image name of C7200-IS-M:
Cisco Internetwork Operating System Software
IOS (tm) 7200 Software (C7200-IS-M), Version 12.2(14)S16, RELEASE SOFTWARE (fc1)
The release train label is "12.2".
The next example shows a product running IOS release 12.3(7)T12 with
an image name of C7200-IK9S-M:
Cisco IOS Software, 7200 Software (C7200-IK9S-M), Version 12.3(7)T12, RELEASE SOFTWARE (fc1)
Additional information about Cisco IOS Banners is available at:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1828/products_white_paper09186a008018305e.shtml#3
Products Confirmed Not Vulnerable
+--------------------------------
Cisco products that do not run IOS are unaffected by this
vulnerability.
Cisco IOS-XR is not affected.
No other Cisco products are currently known to be affected by this
vulnerability.
Details
=======
TCP is the transport layer protocol designed to provide
connection-oriented, reliable delivery of a data stream. To
accomplish this, TCP uses a mixture of flags to indicate state and
sequence numbers to identify the order in which the packets are to be
reassembled. TCP also provides a number, called an acknowledgement
number, that is used to indicate the sequence number of the next
packet expected. The full specification of the TCP protocol can be
found at http://www.ietf.org/rfc/rfc0793.txt
Cisco IOS devices that are configured to receive TCP packets are
exposed to this issue. This Advisory does not apply to traffic that
is transiting the device.
Certain crafted packets destined to an IPv4 address assigned to a
physical or virtual interface on a Cisco IOS device may cause the
device to leak a small amount of memory. Over time, such a memory
leak may lead to memory exhaustion and potentially degraded service.
Although this is an issue with TCP, it is not required to complete
the TCP 3-way handshake in order for the memory leak to be triggered.
Therefore, TCP packets with a spoofed source address may trigger the
leak.
The following document contains additional information on how to
identify if your router is suffering from a memory leak in Processor
memory:
http://www.cisco.com/warp/public/63/mallocfail.shtml#tshoot2
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:
http://intellishield.cisco.com/security/alertmanager/cvss
Cisco Bug IDs:
CSCek37177
CVSS Base Score: 3.3
Access Vector: Remote
Access Complexity: Low
Authentication: Not Required
Confidentiality Impact: None
Integrity Impact: None
Availability Impact: Complete
Impact Bias: Normal
CVSS Temporal Score: 2.7
Exploitability: Functional
Remediation Level: Official Fix
Report Confidence: Confirmed
Impact
======
Successful exploitation of the vulnerability may result in a small
amount of processor memory to leak, which may lead to degraded
service. This issue will not resolve over time, and will require a
device reset to recover the leaked memory.
This vulnerability only applies to traffic destined to the Cisco IOS
device. Traffic transiting the device will not trigger this issue.
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
+------------------------------------------------------------------------+
| Major | Availability of Repaired Releases |
| Release | |
|------------+-----------------------------------------------------------|
| Affected | | |
| 12.0-Based | Rebuild | Maintenance |
| Release | | |
|------------+-----------------------------------------------------------|
| 12.0 | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0DA | Vulnerable; migrate to 12.2(10)DA5 or later |
|------------+-----------------------------------------------------------|
| 12.0DB | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.0DC | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| | 12.0(31)S6 | |
|12.0S |----------------------------+------------------------------|
| | 12.0(32)S4 | |
|------------+-----------------------------------------------------------|
| 12.0SC | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| 12.0SL | Vulnerable; migrate to 12.0(31)S6 or later |
|------------+-----------------------------------------------------------|
| 12.0SP | Vulnerable; migrate to 12.0(31)S6 or later |
|------------+-----------------------------------------------------------|
| 12.0ST | Vulnerable; migrate to 12.0(31)S6 or later |
|------------+-----------------------------------------------------------|
| 12.0SX | 12.0(25)SX11 | |
|------------+----------------------------+------------------------------|
| 12.0SY | | 12.0(32)SY |
|------------+-----------------------------------------------------------|
| 12.0SZ | Vulnerable; migrate to 12.0(31)S6 or later |
|------------+-----------------------------------------------------------|
| 12.0T | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0W | Not vulnerable |
|------------+-----------------------------------------------------------|
| 12.0WC | 12.0(5)WC15 | |
|------------+-----------------------------------------------------------|
| 12.0WT | Not vulnerable |
|------------+-----------------------------------------------------------|
| 12.0XA | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XB | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XC | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XD | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XE | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.0XF | Not vulnerable |
|------------+-----------------------------------------------------------|
| 12.0XG | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XH | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XI | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XJ | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XK | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XL | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XM | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XN | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XQ | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XR | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XS | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.0XV | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.0XW | Not vulnerable |
|------------+-----------------------------------------------------------|
| Affected | | |
| 12.1-Based | Rebuild | Maintenance |
| Release | | |
|------------+-----------------------------------------------------------|
| 12.1 | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1 AA | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1 AX | Vulnerable; migrate to 12.2(25)EY4 or later |
|------------+-----------------------------------------------------------|
| 12.1 AY | Vulnerable; migrate to 12.1(22)EA8 or later |
|------------+-----------------------------------------------------------|
| 12.1 AZ | Vulnerable; migrate to 12.1(22)EA8 or later |
|------------+-----------------------------------------------------------|
| 12.1 CX | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1 DA | Vulnerable; migrate to 12.2(10)DA5 or later |
|------------+-----------------------------------------------------------|
| 12.1 DB | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.1 DC | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| | 12.1(26)E7 | |
|12.1E |----------------------------+------------------------------|
| | 12.1(27b)E1 | |
|------------+----------------------------+------------------------------|
| 12.1EA | 12.1(22)EA8 | |
|------------+-----------------------------------------------------------|
| 12.1EB | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.1EC | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| | 12.1(19)EO6; available on | |
| 12.1EO | 31-Jan-07 | |
| |----------------------------+------------------------------|
| | 12.1(20)EO3 | |
|------------+-----------------------------------------------------------|
| 12.1EU | Vulnerable; migrate to 12.2(25)EWA6 or later |
|------------+-----------------------------------------------------------|
| 12.1EV | Vulnerable; migrate to 12.2(27)SV4 or later |
|------------+-----------------------------------------------------------|
| 12.1EW | Vulnerable; migrate to 12.2(25)EWA6 or later |
|------------+-----------------------------------------------------------|
| 12.1EX | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.1EY | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.1EZ | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.1T | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XA | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XB | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XC | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XD | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XE | Vulnerable; migrate to 12.1(26)E7 or later |
|------------+-----------------------------------------------------------|
| 12.1XF | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XG | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XH | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XI | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XJ | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XL | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XM | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XP | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XQ | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XR | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XS | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XT | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XU | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XV | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1XW | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XX | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XY | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1XZ | Vulnerable; migrate to 12.2(37) or later |
|------------+-----------------------------------------------------------|
| 12.1YA | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YB | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YC | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YD | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YE | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YF | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YH | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YI | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.1YJ | Vulnerable; migrate to 12.1(22)EA8 or later |
|------------+-----------------------------------------------------------|
| Affected | | |
| 12.2-Based | Rebuild | Maintenance |
| Release | | |
|------------+----------------------------+------------------------------|
| 12.2 | | 12.2(37) |
|------------+-----------------------------------------------------------|
| 12.2B | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2BC | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| 12.2BW | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2BY | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2BZ | Vulnerable; migrate to 12.3(7)XI8 or later |
|------------+-----------------------------------------------------------|
| 12.2CX | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| 12.2CY | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| 12.2CZ | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| | 12.2(10)DA5 | |
|12.2DA |----------------------------+------------------------------|
| | 12.2(12)DA10 | |
|------------+-----------------------------------------------------------|
| 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 | 12.2(25)EX1 | |
|------------+----------------------------+------------------------------|
| 12.2EY | 12.2(25)EY4 | |
|------------+-----------------------------------------------------------|
| 12.2EZ | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------+-----------------------------------------------------------|
| 12.2FX | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------+-----------------------------------------------------------|
| 12.2FY | Vulnerable; migrate to 12.2(25)SEE1 or later |
|------------+-----------------------------------------------------------|
| 12.2FZ | All 12.2FZ releases are fixed |
|------------+-----------------------------------------------------------|
| 12.2IXA | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2IXB | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2IXC | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2JA | Vulnerable; migrate to 12.3(8)JA2 or later |
|------------+-----------------------------------------------------------|
| 12.2JK | Vulnerable; migrate to 12.4(4)T4 or later |
|------------+-----------------------------------------------------------|
| 12.2MB | Vulnerable; migrate to 12.2(25)SW8 or later |
|------------+-----------------------------------------------------------|
| 12.2MC | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.2S | 12.2(25)S12; Available | |
| | 12-Feb-07 | |
|------------+----------------------------+------------------------------|
| 12.2SB | 12.2(28)SB2 | 12.2(31)SB |
|------------+----------------------------+------------------------------|
| 12.2SBC | 12.2(27)SBC5 | |
|------------+----------------------------+------------------------------|
| 12.2SE | | 12.2(35)SE |
|------------+-----------------------------------------------------------|
| 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 | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2SGA | All 12.2SGA releases are fixed |
|------------+-----------------------------------------------------------|
| 12.2SO | 12.2(18)SO7 | |
|------------+-----------------------------------------------------------|
| 12.2SRA | All 12.2SRA releases are fixed |
|------------+-----------------------------------------------------------|
| 12.2SRB | All 12.2SRB releases are fixed |
|------------+-----------------------------------------------------------|
| 12.2SU | Vulnerable; migrate to 12.4(8) or later |
|------------+-----------------------------------------------------------|
| | 12.2(27)SV4 | |
| |----------------------------+------------------------------|
| 12.2SV | 12.2(28)SV1 | |
| |----------------------------+------------------------------|
| | 12.2(29)SV1 | |
|------------+----------------------------+------------------------------|
| 12.2SW | 12.2(25)SW8 | |
|------------+-----------------------------------------------------------|
| 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)S12 or later; Available |
| | 12-Feb-07 |
|------------+-----------------------------------------------------------|
| 12.2T | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2TPC | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2XA | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XB | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XC | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2XD | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XE | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XF | Vulnerable; migrate to 12.3(13a)BC6 or later |
|------------+-----------------------------------------------------------|
| 12.2XG | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XH | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XI | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XJ | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XK | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XL | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XM | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XN | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XQ | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XR | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XS | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XT | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XU | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XV | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2XW | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YA | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YB | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YC | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YD | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.2YE | Vulnerable; migrate to 12.2(25)S12 or later; Available |
| | 12-Feb-07 |
|------------+-----------------------------------------------------------|
| 12.2YF | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YG | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YH | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YJ | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YK | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 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 | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2YQ | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2YR | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2YS | Not vulnerable |
|------------+-----------------------------------------------------------|
| 12.2YT | Vulnerable; migrate to 12.3(19) 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 12.4(8) or later |
|------------+-----------------------------------------------------------|
| 12.2YY | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2YZ | Vulnerable; migrate to 12.2(25)S12 or later; Available |
| | 12-Feb-07 |
|------------+-----------------------------------------------------------|
| 12.2ZA | Vulnerable; migrate to 12.2(18)SXD7a or later |
|------------+-----------------------------------------------------------|
| 12.2ZB | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2ZC | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2ZD | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.2ZE | Vulnerable; migrate to 12.3(19) or later |
|------------+-----------------------------------------------------------|
| 12.2ZF | Vulnerable; migrate to 12.3(4)T13 or later |
|------------+-----------------------------------------------------------|
| 12.2ZG | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 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 | Vulnerable; migrate to 12.4(8) or later |
|------------+-----------------------------------------------------------|
| Affected | | |
| 12.3-Based | Rebuild | Maintenance |
| Release | | |
|------------+----------------------------+------------------------------|
| 12.3 | 12.3(10f) | 12.3(19) |
|------------+-----------------------------------------------------------|
| 12.3B | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| | 12.3(13a)BC6 | |
|12.3BC |----------------------------+------------------------------|
| | 12.3(17a)BC2 | |
|------------+-----------------------------------------------------------|
| 12.3BW | Vulnerable; migrate to 13.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.3JA | 12.3(8)JA2 | |
|------------+-----------------------------------------------------------|
| 12.3JEA | All 12.3JEA releases are fixed |
|------------+-----------------------------------------------------------|
| 12.3JEB | All 12.3JEB releases are fixed |
|------------+-----------------------------------------------------------|
| 12.3JK | 12.3(2)JK2 | |
|------------+----------------------------+------------------------------|
| 12.3JX | 12.3(7)JX4 | 12.3(11)JX |
|------------+----------------------------+------------------------------|
| | 12.3(4)T13 | |
|12.3T |----------------------------+------------------------------|
| | 12.3(11)T11 | |
|------------+-----------------------------------------------------------|
| 12.3TPC | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3XA | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3XB | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.3XC | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3XD | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.3XE | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3XF | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.3XG | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3XH | Vulnerable; migrate to 12.3(11)T11 or later |
|------------+-----------------------------------------------------------|
| 12.3XI | 12.3(7)XI8 | |
|------------+-----------------------------------------------------------|
| 12.3XJ | Vulnerable; migrate to 12.3(14)YX2 or later |
|------------+-----------------------------------------------------------|
| 12.3XK | Vulnerable; migrate to 12.4(8) 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)T5 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 | Vulnerable; migrate to 12.4(8) or later |
|------------+-----------------------------------------------------------|
| 12.3YA | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3YD | Vulnerable; migrate to 12.4(2)T5 or later |
|------------+-----------------------------------------------------------|
| 12.3YF | Vulnerable; migrate to 12.3(14)YX2 or later |
|------------+-----------------------------------------------------------|
| 12.3YG | Vulnerable; migrate to 12.4(2)T5 or later |
|------------+-----------------------------------------------------------|
| 12.3YH | Vulnerable; migrate to 12.4(2)T5 or later |
|------------+-----------------------------------------------------------|
| 12.3YI | Vulnerable; migrate to 12.4(2)T5 or later |
|------------+-----------------------------------------------------------|
| 12.3YJ | Vulnerable; migrate to 12.3(14)YQ8 or later |
|------------+-----------------------------------------------------------|
| 12.3YK | Vulnerable; migrate to 12.4(4)T4 or later |
|------------+-----------------------------------------------------------|
| 12.3YM | 12.3(14)YM8 | |
|------------+----------------------------+------------------------------|
| 12.3YQ | 12.3(14)YQ8 | |
|------------+-----------------------------------------------------------|
| 12.3YS | Vulnerable; migrate to 12.4(4)T4 or later |
|------------+-----------------------------------------------------------|
| 12.3YT | Vulnerable; migrate to 12.4(4)T4 or later |
|------------+-----------------------------------------------------------|
| 12.3YU | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.3YX | 12.3(14)YX2 | |
|------------+----------------------------+------------------------------|
| 12.3YZ | 12.3(11)YZ1 | |
|------------+----------------------------+------------------------------|
| Affected | | |
| 12.4-Based | Rebuild | Maintenance |
| Release | | |
|------------+----------------------------+------------------------------|
| | 12.4(3e) | |
|12.4 |----------------------------+------------------------------|
| | 12.4(7b) | 12.4(8) |
|------------+----------------------------+------------------------------|
| 12.4MR | 12.4(6)MR1 | |
|------------+-----------------------------------------------------------|
| 12.4SW | All 12.4SW releases are fixed |
|------------+-----------------------------------------------------------|
| | 12.4(2)T5 | |
| |----------------------------+------------------------------|
| 12.4T | 12.4(4)T4 | |
| |----------------------------+------------------------------|
| | 12.4(6)T3 | 12.4(9)T |
|------------+-----------------------------------------------------------|
| 12.4XA | Vulnerable; migrate to 12.4(6)T3 |
|------------+-----------------------------------------------------------|
| 12.4XB | Vulnerable; contact TAC |
|------------+-----------------------------------------------------------|
| 12.4XC | 12.4(4)XC3 | |
|------------+----------------------------+------------------------------|
| 12.4XD | 12.4(4)XD4 | |
|------------+-----------------------------------------------------------|
| 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
===========
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-crafted-tcp.shtml
Note: Configuring VTY access-class filters is not an effective
mitigation strategy for this vulnerability.
Infrastructure ACLs (iACL)
+-------------------------
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 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 ACL example shown 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.
A sample access list for devices running Cisco IOS is below:
!--- Permit TCP services from trust hosts destined
!--- to infrastructure addresses.
access-list 150 permit tcp TRUSTED_HOSTS MASK INFRASTRUCTURE_ADDRESSES MASK
!--- Deny TCP packets from all other sources destined to infrastructure addresses.
access-list 150 deny tcp any INFRASTRUCTURE_ADDRESSES MASK
!--- Permit all other traffic to transit the device.
access-list 150 permit IP any any
interface serial 2/0
ip access-group 150 in
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 here:
http://www.cisco.com/warp/public/707/iacl.html
Receive ACLs (rACL)
+------------------
For distributed platforms, Receive ACLs may be an option starting in
Cisco IOS Software Versions 12.0(21)S2 for the 12000 (GSR), 12.0(24)S
for the 7500, and 12.0(31)S for the 10720. The Receive ACL protects
the device from harmful traffic before the traffic can impact the
route processor. Receive ACLs are designed to only protect the device
on which it is configured. On the 12000, transit traffic is never
affected by a receive ACL. Because of this, the destination IP
address "any" used in the example ACL entries below only refer to the
router's own physical or virtual IP addresses. On the 7500 and 10720,
transit traffic with IP options set will be subject to the Receive
ACL and permitted or denied accordingly. Receive 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 "GSR:
Receive Access Control Lists" will help you identify and allow
legitimate traffic to your device and deny all unwanted packets:
http://www.cisco.com/warp/public/707/racl.html
The following is the receive path ACL written to permit this type of
traffic from trusted hosts:
!--- Permit tcp services from trusted hosts allowed to the RP.
access-list 151 permit tcp TRUSTED_ADDRESSES MASK any
!--- Deny tcp services from all other sources to the RP.
access-list 151 deny tcp any any
!--- Permit all other traffic to the RP.
access-list 151 permit ip any any
!--- Apply this access list to the 'receive' path.
ip receive access-list 151
Control Plane Policing (CoPP)
+----------------------------
The Control Plane Policing (CoPP) feature may be used to mitigate
this vulnerability. In the following example, only TCP traffic from
trusted hosts and with 'receive' destination IP addresses is
permitted to reach the route processor (RP). All other 'transit' IP
traffic is unaffected.
It should be noted that dropping traffic from unknown or untrusted IP
addresses may affect hosts with dynamically assigned IP addresses
from connecting to the Cisco IOS device.
access-list 152 deny tcp TRUSTED_ADDRESSES MASK any
access-list 152 permit tcp any any
access-list 152 deny ip any any
!
class-map match-all permit-tcp-class
match access-group 152
!
!
policy-map permit-tcp-policy
class permit-tcp-class
drop
!
control-plane
service-policy input permit-tcp-policy
In the above CoPP example, the ACL entries that match the exploit
packets with the "permit" action result in these packets being
discarded by the policy-map "drop" function, while packets that match
the "deny" action are not affected by the policy-map drop function.
Please note that in the 12.2S and 12.0S Cisco IOS trains the
policy-map syntax is different:
policy-map permit-tcp-policy
class class permit-tcp-class
police 32000 1500 1500 conform-action drop exceed-action drop
CoPP is available in Cisco IOS release trains 12.0S, 12.2SX, 12.2S,
12.3T, 12.4, and 12.4T.
Additional information on the configuration and use of the CoPP
feature can be found at the following URL:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1838/products_white_paper09186a0080211f39.shtml
Anti-spoofing
+------------
The Unicast Reverse Path Forwarding (Unicast RPF or uRPF) feature
helps to mitigate problems that are caused by spoofed IP source
addresses. It is available on Cisco routers and firewalls. For
further details, please refer to:
http://www.cisco.com/en/US/partner/products/ps6441/products_command_reference_chapter09186a00804ae49f.html#wp1229984
By enabling Unicast Reverse Path Forwarding (uRPF), all spoofed
packets will be dropped at the first device. To enable uRPF, use the
following commands.
router(config)# ip cef
router(config)# interface interface #
router(config-if)# ip verify unicast source reachable-via rx
BGP and BTSH/GTSM
+----------------
Depending on your release of software, it may be possible to protect
your BGP sessions from this memory leak. With the introduction of
CSCee73956, Cisco IOS has improved support for BTSH (BGP TTL Security
Hack) to reduce, if not eliminate a risk of a memory leak due to this
vulnerability. This functionality is also known as GTSM (Generalized
TTL Security Mechanism) and documented in RFC 3682. This section
refers to GTSM as applied to eBGP sessions only.
Releases of Cisco IOS that contain CSCee73956 are protected from this
attack against the BGP port (TCP port 179) only. Other ports should
be protected accordingly.
BTSH is not supported for iBGP sessions. BTSH was first introduced in
Cisco IOS in 12.0(27)S, 12.3(7)T and 12.2(25)S. Note that the BTSH
feature prior to CSCee73956 will not protect against this
vulnerability.
For more information on BTSH, please see:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123newft/123t/123t_7/gt_btsh.htm
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 "[email protected]" or "[email protected]"
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: [email protected]
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 discovered by Cisco during our internal
testing process.
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-crafted-tcp.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.
* [email protected]
* [email protected]
* [email protected]
* [email protected]
* [email protected]
* [email protected]
* [email protected]
* [email protected]
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
================
+---------------------------------------+
| | | Initial |
| 1.0 | 2007-January-24 | 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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