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Cisco Security Advisory: Crafted IP Option Vulnerability
Advisory ID: cisco-sa-20070124-crafted-ip-option
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-ip-option.shtml
Revision 1.0
For Public Release 2007 January 24 1600 UTC (GMT)
+--------------------------------------------------------------------
Contents
========
Summary
Affected Products
Details
Vulnerability Scoring Details
Impact
Software Version and Fixes
Workarounds
Obtaining Fixed Software
Exploitation and Public Announcements
Status of this Notice: FINAL
Distribution
Revision History
Cisco Security Procedures
- ---------------------------------------------------------------------
Summary
=======
Cisco routers and switches running Cisco IOSŪ or Cisco IOS XR
software may be vulnerable to a remotely exploitable crafted IP
option Denial of Service (DoS) attack. Exploitation of the
vulnerability may potentially allow for arbitrary code execution. The
vulnerability may be exploited after processing an Internet Control
Message Protocol (ICMP) packet, Protocol Independent Multicast
version 2 (PIMv2) packet, Pragmatic General Multicast (PGM) packet,
or URL Rendezvous Directory (URD) packet containing a specific
crafted IP option in the packet's IP header. No other IP protocols
are affected by this issue.
Cisco has made free software available to address this vulnerability
for affected customers.
There are workarounds available to mitigate the effects of the
vulnerability.
This vulnerability was discovered during internal testing.
This advisory is available at
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-ip-option.shtml
Affected Products
=================
Vulnerable Products
+------------------
This issue affects all Cisco devices running Cisco IOS or Cisco IOS
XR software and configured to process Internet Protocol version 4
(IPv4) 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.
This vulnerability is present in all unfixed versions of Cisco IOS XR
software, including versions 2.0.X, 3.0.X, and 3.2.X.
All versions of Cisco IOS or Cisco IOS XR prior to the versions
listed in the Fixed Software table below may be susceptible to this
vulnerability.
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. Cisco IOS XR software
will identify itself as "Cisco IOS XR Software" followed by "Version"
and the version number. 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
Cisco IOS XR Software is a member of the Cisco IOS software family
that uses a microkernel-based distributed operating system
infrastructure. Cisco IOS XR runs only on Cisco Carrier Routing
System 1 (CRS-1) and Cisco XR 12000 series routers.
Additional information about Cisco IOS XR is available at
http://www.cisco.com/en/US/products/ps5845/index.html
The following example shows partial output from the show version
command which identifies a Cisco product running Cisco IOS XR release
3.3.0:
RP/0/RP0/CPU0:router#show version
Cisco IOS XR Software, Version 3.3.0
Copyright (c) 2006 by cisco Systems, Inc.
ROM: System Bootstrap, Version 1.32(20050525:193559) [CRS-1 ROMMON]
Products Confirmed Not Vulnerable
+--------------------------------
Cisco devices that do not run Cisco IOS or Cisco IOS XR software are
not affected. CatOS software is not affected by this issue.
No other Cisco products are currently known to be affected by this
vulnerability.
Details
=======
This vulnerability may be exploited when an affected device processes
a packet that meets all three of the following conditions:
+---------------------------------------+
| 1. The packet contains a specific |
| crafted IP option. |
|---------------------------------------|
| AND |
|---------------------------------------|
| 2. The packet is one of the following |
| protocols: |
|---------------------------------------|
| * ICMP - Echo (Type 8) - 'ping' |
|---------------------------------------|
| * ICMP - Timestamp (Type 13) |
|---------------------------------------|
| * ICMP - Information Request (Type |
| 15) |
|---------------------------------------|
| * ICMP - Address Mask Request (Type |
| 17) |
|---------------------------------------|
| * PIMv2 - IP protocol 103 |
|---------------------------------------|
| * PGM - IP protocol 113 |
|---------------------------------------|
| * URD - TCP Port 465 |
|---------------------------------------|
| AND |
|---------------------------------------|
| 3. The packet is sent to a physical |
| or virtual IPv4 address configured on |
| the affected device. |
+---------------------------------------+
No other ICMP message types are affected by this issue.
No other IP protocols are affected by this issue.
No other TCP services are affected by this issue.
The packet can be sent from a local network or from a remote network.
The source IP address of the packet can be spoofed or non-spoofed.
Packets which transit the device (packets not sent to one of the
device's IP addresses) do not trigger the vulnerability and the
device is not affected.
This vulnerability is documented in these Bug IDs:
* Cisco Bug ID CSCec71950 for Cisco IOS
* Cisco Bug ID CSCeh52410 for Cisco IOS XR
Cisco IOS
+--------
A crafted packet addressed directly to a vulnerable device running
Cisco IOS software may result in the device reloading or may allow
execution of arbitrary code.
Cisco IOS XR
+-----------
A crafted packet addressed directly to a vulnerable device running
Cisco IOS XR software may result in the ipv4_io process restarting or
may allow execution of arbitrary code. CRS-1 Nodes that run the
ipv4_io process include Route Processors (RP), Distributed Route
Processors (DRP), Modular Services Cards (MSC), and XR 12000 Line
Cards. While the ipv4_io process is restarting, all ICMP traffic
destined for the device itself and exception punts will be dropped.
Examples of exception punts include packets having IP header
information that requires further processing such as IP options,
Time-to-Live equal to 0 or 1, and layer-2 keepalives. CLNS traffic to
the Node or Line Card is not affected. If the ipv4_io process is
restarted several times consecutively, the CRS-1 Node or XR 12000
Line Card may reload, causing a Denial of Service (DoS) condition for
the transit traffic switched on that Node or Line card.
Devices Configured for ICMP Message Types
+----------------------------------------
ICMP Type 8
+----------
By default, devices running all Cisco IOS and Cisco IOS XR versions
will process ICMP echo-request (Type 8) packets. This behavior cannot
be modified.
ICMP Type 13
+-----------
By default, devices running all Cisco IOS versions will process ICMP
timestamp (Type 13) packets. This behavior cannot be modified.
By default, devices running all Cisco IOS XR versions will NOT
process ICMP timestamp (Type 13) packets. This behavior cannot be
modified.
ICMP Type 15
+-----------
With the introduction of CSCdz50424, by default routers will NOT
process ICMP information request (Type 15) packets. Releases of Cisco
IOS that contain CSCdz50424 include 12.3, 12.3T, 12.4, 12.4T, later
12.0S and later 12.2S. See CSCdz50424 for complete release
information.
A router running a Cisco IOS release containing CSCdz50424 that has
been modified to process ICMP information request packets will have
the interface configuration statement "ip information-reply", which
can be seen by issuing the command "show running-config" as shown
in the following examples:
router#show running-config | include information-reply
ip information-reply
or
router#show running-config
interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip information-reply
By default, devices running all other Cisco IOS versions will process
ICMP information request (Type 15) packets. This behavior cannot be
modified. Since this is the default behavior, "ip information-reply"
will not be visible in the device's configuration.
By default, devices running all Cisco IOS XR versions will NOT
process ICMP information request (Type 15) packets. This behavior
cannot be modified.
ICMP Type 17
+-----------
Beginning in Cisco IOS version 10.0, by default devices will NOT
process ICMP address mask request (Type 17) packets. A router that
has been modified to process ICMP address mask request packets will
have the interface configuration statement "ip mask-reply", which
can be seen by issuing the command "show running-config" as shown
in the following examples:
router#show running-config | include mask-reply
ip mask-reply
or
router#show running-config
interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip mask-reply
By default, devices running all Cisco IOS XR versions will NOT
process ICMP address mask request (Type 17) packets. A router that
has been modified to process ICMP address mask request packets will
have the interface configuration statement "ipv4 mask-reply", which
can be seen by issuing the command show running-config as shown in
the following examples:
RP/0/RP0/CPU0:router#show running-config | include mask-reply
Building configuration...
ipv4 mask-reply
or
RP/0/RP0/CPU0:router#show running-config
interface POS0/1/3/0
ipv4 address 192.0.2.1 255.255.255.252
ipv4 mask-reply
Devices Configured for Protocol Independent Multicast Version 2
(PIMv2)
+--------------------------------------------------------------
Cisco IOS
+--------
A router running Cisco IOS that is configured to process PIMv2
packets will have an interface configuration statement that begins
with "ip pim", which can be seen by issuing the command "show
running-config" as shown in the following examples:
router#show running-config | include ip pim
ip pim sparse-mode
or
router#show running-config
interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
The command "show ip pim interface" can also be used to determine
if a router is configured to process PIMv2 packets, as shown in
the following example:
router#show ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
192.0.2.1 FastEthernet0/0 v1/S 0 30 1 0.0.0.0
192.168.1.1 FastEthernet1/0 v2/SD 0 30 1 0.0.0.0
Interfaces running PIMv2 will show "v2/" under the Ver/Mode column.
Interfaces without PIM configured will not be shown in the command
output.
PIMv2 is the default PIM version. Routers configured to process only
PIMv1 messages are not vulnerable to the PIMv2 exploit. Routers that
do not have PIM configured are not vulnerable to the PIMv2 exploit.
PIM is not enabled by default.
Additional information about PIM is available at
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca794.html
Cisco IOS XR
+-----------
The command show pim interface can be used to determine if a router
running Cisco IOS XR is configured to process PIMv2 packets, as shown
in the following example:
RP/0/0/CPU0:router#show pim interface
Address Interface PIM Nbr Hello DR DR
Count Intvl Prior
192.168.1.1 Loopback0 on 1 30 1 this system
192.168.2.1 MgmtEth0/0/CPU0/0 off 0 30 1 not elected
192.168.3.1 Loopback1 on 1 30 1 this system
192.168.4.1 Loopback3 on 1 30 1 this system
192.168.5.1 POS0/4/0/0 on 1 30 1 this system
192.0.2.1 POS0/4/0/1 on 1 30 1 this system
Interfaces running PIMv2 will show on under the PIM column.
Interfaces without PIM configured will show "off" under the PIM
column.
Cisco IOS XR does not support PIMv1. PIM is not enabled by default on
Cisco IOS XR.
Additional information about PIM on Cisco IOS XR is available at
http://www.cisco.com/en/US/products/ps5845/products_configuration_guide_chapter09186a008069a8a2.html
Devices Configured for Pragmatic General Multicast (PGM)
+-------------------------------------------------------
A router that is configured to process PGM packets will have the
interface configuration statement "ip pgm router", which can be
seen by issuing the command "show running-config" as shown in
the following examples:
router#show running-config | include ip pgm
ip pgm router
or
router#show running-config
interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
ip pgm router
or
router#show running-config
interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pgm router
Routers that do not have PGM configured are not vulnerable to the PGM
exploit. PGM is not enabled by default.
Additional information about PGM is available at
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca798.html
Cisco IOS XR does not support PGM and is not affected by PGM packets
that exploit this vulnerability.
Devices Configured for URL Rendezvous Directory (URD)
+----------------------------------------------------
A router that is configured to process URD packets will have the
interface configuration statement "ip urd" or "ip urd proxy",
which can be seen by issuing the command "show running-config"
as shown in the following examples:
router#show running-config | include ip urd
ip urd
or
router#show running-config | include ip urd
ip urd proxy
or
router#show running-config
interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-mode
ip urd
or
router#show running-config
interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
ip urd proxy
or
router#show running-config
interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip urd
Routers that do not have URD configured are not vulnerable to the URD
exploit. URD is not enabled by default.
Additional information about URD is available at
http://www.cisco.com/en/US/products/sw/iosswrel/ps1835/products_configuration_guide_chapter09186a00800ca795.html
Cisco IOS XR does not support URD and is not affected by URD packets
that exploit this vulnerability.
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
CSCec71950 - Crafted IP Option may cause DoS or code execution
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
CSCeh52410 - Crafted IP Option may cause ipv4-io DoS or code
execution
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
======
Cisco IOS
+--------
Successful exploitation of the vulnerability on Cisco IOS may result
in a reload of the device or execution of arbitrary code. Repeated
exploitation could result in a sustained DoS attack.
Cisco IOS XR
+-----------
Successful exploitation of the vulnerability on Cisco IOS XR may
result in the ipv4_io process restarting or execution of arbitrary
code. Repeated exploitation could result in a CRS-1 Node or XR 12000
Line Card reload and sustained DoS attack.
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/en/US/products/sw/iosswrel/ps1828/products_white_paper09186a008018305e.shtml
Note: There are three IOS security advisories and one field notice
being published on January 24, 2007. Each advisory lists only 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 24, 2007. Links
for the advisories and field notice are listed here.
* http://www.cisco.com/warp/public/707/cisco-sa-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/customer/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 | Availability of Repaired |
| Release | Releases |
|------------+--------------------------|
| 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 |
|------------+--------------------------|
| 12.0S | 12.0(27)S3 | 12.0(28)S |
|------------+--------------------------|
| 12.0SC | Vulnerable; migrate to |
| | 12.3(9a)BC or later |
|------------+--------------------------|
| 12.0SL | Vulnerable; migrate to |
| | 12.0(28)S or later |
|------------+--------------------------|
| 12.0SP | Vulnerable; migrate to |
| | 12.0(28)S or later |
|------------+--------------------------|
| 12.0ST | Vulnerable; migrate to |
| | 12.0(28)S or later |
|------------+--------------------------|
| 12.0SX | 12.0(25) | 12.0(30)SX |
| | SX11 | |
|------------+------------+-------------|
| 12.0SY | | 12.0(27)SY |
|------------+------------+-------------|
| 12.0SZ | | 12.0(30)SZ |
|------------+--------------------------|
| 12.0T | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| | 12.0(28)W5 | |
| 12.0W | (32c); | |
| | available | |
| | 31-Jan-07 | |
|------------+------------+-------------|
| 12.0WC | 12.0(5) | |
| | WC15 | |
|------------+--------------------------|
| 12.0WT | Vulnerable; contact TAC |
|------------+--------------------------|
| 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(23)E 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(23)E or later |
|------------+--------------------------|
| 12.0XV | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| 12.0XW | Vulnerable; migrate to |
| | 12.0(5)WC15 or later |
|------------+--------------------------|
| Affected | | |
| 12.1-Based | Rebuild | Maintenance |
| Release | | |
|------------+--------------------------|
| 12.1 | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| 12.1AA | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| | Vulnerable; for |
| | c3750-ME, migrate to |
| 12.1AX | 12.2(25)EY or later. For |
| | c2970 and 3750, migrate |
| | to 12.2(25)SE or later. |
|------------+--------------------------|
| 12.1AY | Vulnerable; migrate to |
| | 12.1(22)EA8 |
|------------+--------------------------|
| 12.1AZ | Vulnerable; migrate to |
| | 12.1(22)EA8 |
|------------+--------------------------|
| 12.1CX | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| 12.1DA | Vulnerable; migrate to |
| | 12.2(10)DA5 or later |
|------------+--------------------------|
| 12.1DB | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.1DC | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.1E | | 12.1(23)E |
|------------+------------+-------------|
| 12.1EA | 12.1(22) | |
| | EA8 | |
|------------+------------+-------------|
| 12.1EB | | 12.1(23)EB |
|------------+--------------------------|
| 12.1EC | Vulnerable; migrate to |
| | 12.3(9a)BC or later |
|------------+--------------------------|
| | 12.1(19) | |
| | EO6, | |
| | available | |
| 12.1EO | 31-Jan-07 | |
| |------------+-------------|
| | 12.1(20) | |
| | EO3 | |
|------------+--------------------------|
| 12.1EU | Vulnerable; migrate to |
| | 12.2(25)EWA or later |
|------------+--------------------------|
| 12.1EV | Vulnerable; migrate to |
| | 12.2(26)SV1 or later |
|------------+--------------------------|
| 12.1EW | Vulnerable; migrate to |
| | 12.2(18)EW3 or later |
|------------+--------------------------|
| 12.1EX | Vulnerable; migrate to |
| | 12.1(23)E or later |
|------------+--------------------------|
| 12.1EY | Vulnerable; migrate to |
| | 12.1(23)E or later |
|------------+--------------------------|
| 12.1EZ | Vulnerable; migrate to |
| | 12.1(23)E 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(23)E or later |
|------------+--------------------------|
| 12.1XF | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XG | Vulnerable; migrate to |
| | 12.3(8) 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(8) or later |
|------------+--------------------------|
| 12.1XL | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XM | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XP | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XQ | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XR | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XS | Vulnerable; migrate to |
| | 12.2(37)or later |
|------------+--------------------------|
| 12.1XT | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XU | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1XV | Vulnerable; migrate to |
| | 12.3(8) 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(8) or later |
|------------+--------------------------|
| 12.1YB | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YC | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YD | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YE | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YF | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YH | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YI | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.1YJ | Vulnerable; migrate to |
| | 12.1(22)EA8 |
|------------+--------------------------|
| Affected | | |
| 12.2-Based | Rebuild | Maintenance |
| Release | | |
|------------+------------+-------------|
| 12.2 | 12.2(34a) | 12.2(37) |
|------------+--------------------------|
| 12.2B | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.BC | Vulnerable; migrate to |
| | 12.3(9a)BC or later |
|------------+--------------------------|
| 12.2BW | Vulnerable; migrate to |
| | 12.3(8) 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(9a)BC or later |
|------------+--------------------------|
| 12.2CY | Vulnerable; migrate to |
| | 12.3(9a)BC 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)EWA5 or later |
|------------+--------------------------|
| | 12.2(18) | |
| | EW3 | |
|12.2EW |------------+-------------|
| | 12.2(20) | 12.2(25)EW |
| | EW4 | |
|------------+------------+-------------|
| 12.2EWA | 12.2(20) | 12.2(25)EWA |
| | EWA4 | |
|------------+------------+-------------|
| 12.2EX | | 12.2(25)EX |
|------------+--------------------------|
| 12.2EY | All 12.2EY releases are |
| | fixed |
|------------+--------------------------|
| 12.2EZ | All 12.2EZ releases are |
| | fixed |
|------------+--------------------------|
| 12.2FX | All 12.2FX releases are |
| | fixed |
|------------+--------------------------|
| 12.2FY | All 12.2FY releases are |
| | fixed |
|------------+--------------------------|
| 12.2FZ | All 12.2FZ releases are |
| | fixed |
|------------+--------------------------|
| 12.2IXA | All 12.2IXA releases are |
| | fixed |
|------------+--------------------------|
| 12.2IXB | All 12.2IXB releases are |
| | fixed |
|------------+--------------------------|
| 12.2IXC | All 12.2IXC releases are |
| | fixed |
|------------+--------------------------|
| 12.2JA | Vulnerable; migrate to |
| | 12.3(8)JA or later |
|------------+--------------------------|
| 12.2JK | Vulnerable; migrate to |
| | 12.4(4)T or later |
|------------+--------------------------|
| 12.2MB | Vulnerable; migrate to |
| | 12.2(25)SW1 or later |
|------------+--------------------------|
| 12.2MC | 12.2(15)MC2h |
|------------+--------------------------|
| 12.2S | | 12.2(25)S |
|------------+------------+-------------|
| 12.2SB | | 12.2(28)SB |
|------------+--------------------------|
| 12.2SBC | All 12.2SBC releases are |
| | fixed |
|------------+--------------------------|
| 12.2SE | | 12.2(25)SE |
|------------+--------------------------|
| 12.2SEA | All 12.2SEA releases are |
| | fixed |
|------------+--------------------------|
| 12.2SEB | All 12.2SEB releases are |
| | fixed |
|------------+--------------------------|
| 12.2SEC | All 12.2SEC releases are |
| | fixed |
|------------+--------------------------|
| 12.2SED | All 12.2SED releases are |
| | fixed |
|------------+--------------------------|
| 12.2SEE | All 12.2SEE releases are |
| | fixed |
|------------+--------------------------|
| 12.2SEF | All 12.2SEF releases are |
| | fixed |
|------------+--------------------------|
| 12.2SEG | All 12.2SEG releases are |
| | fixed |
|------------+--------------------------|
| 12.2SG | All 12.2SG releases are |
| | fixed |
|------------+--------------------------|
| 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 |
| | 12.3(14)T or later |
|------------+--------------------------|
| 12.2SV | | 12.2(23)SV |
|------------+------------+-------------|
| 12.2SW | 12.2(25) | |
| | SW1 | |
|------------+--------------------------|
| 12.2SX | Vulnerable; migrate to |
| | 12.2(17d)SXB11a or later |
|------------+--------------------------|
| 12.2SXA | Vulnerable; migrate to |
| | 12.2(17d)SXB11a or later |
|------------+--------------------------|
| 12.2SXB | 12.2(17d) | |
| | SXB11a | |
|------------+------------+-------------|
| 12.2SXD | 12.2(18) | |
| | SXD7a | |
|------------+--------------------------|
| 12.2SXE | All 12.2SXE releases are |
| | fixed |
|------------+--------------------------|
| 12.2SXF | All 12.2SXF releases are |
| | fixed |
|------------+--------------------------|
| 12.2SY | Vulnerable; migrate to |
| | 12.2(17d)SXB11a or later |
|------------+--------------------------|
| 12.2SZ | Vulnerable; migrate to |
| | 12.2(25)S or later |
|------------+--------------------------|
| 12.2T | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2TPC | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.2XA | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XB | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XC | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2XD | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XE | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XF | Vulnerable; migrate to |
| | 12.3(9a)BC or later |
|------------+--------------------------|
| 12.2XG | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XH | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XI | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XJ | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XK | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XL | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XM | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XN | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XQ | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XR | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XS | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XT | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XU | Vulnerable; migrate to |
| | 12.3(12) or later |
|------------+--------------------------|
| 12.2XV | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2XW | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YA | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YB | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YC | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YD | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YE | Vulnerable; migrate to |
| | 12.2(25)S or later |
|------------+--------------------------|
| 12.2YF | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YG | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YH | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YJ | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YK | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YL | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YM | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YN | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YO | Not vulnerable |
|------------+--------------------------|
| 12.2YP | Vulnerable; migrate to |
| | 12.3(8) 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 | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YT | Vulnerable; migrate to |
| | 12.3(8) or later |
|------------+--------------------------|
| 12.2YU | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YV | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.2YW | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2YX | Vulnerable; migrate to |
| | 12.3(14)T or later |
|------------+--------------------------|
| 12.2YY | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.2YZ | Vulnerable; migrate to |
| | 12.2(25)S or later |
|------------+--------------------------|
| 12.2ZA | Vulnerable; migrate to |
| | 12.2(17d)SXBa or later |
|------------+--------------------------|
| 12.2ZB | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2ZC | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2ZD | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.2ZE | Vulnerable; migrate to |
| | 12.3(8) or laer |
|------------+--------------------------|
| 12.2ZF | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| | Vulnerable; for SOHO9x, |
| 12.2ZG | migrate to 12.3(8)YG2 or |
| | later. For c83x, migrate |
| | to 12.3(2)XA3 or later |
|------------+--------------------------|
| 12.2ZH | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.2ZJ | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.2ZL | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.2ZN | Vulnerable; migrate to |
| | 12.3(4)T13 or later |
|------------+--------------------------|
| 12.2ZP | Vulnerable; migrate to |
| | 12.3(8)XY or later |
|------------+--------------------------|
| Affected | | |
| 12.3-Based | Rebuild | Maintenance |
| Release | | |
|------------+------------+-------------|
| 12.3 | | 12.3(8) |
|------------+--------------------------|
| 12.3B | Vulnerable; migrate to |
| | 12.3(8)T7 or later |
|------------+--------------------------|
| 12.3BC | | 12.3(9a)BC |
|------------+--------------------------|
| 12.3BW | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.3JA | | 12.3(8)JA |
|------------+--------------------------|
| 12.3JEA | All 12.3JEA releases are |
| | fixed |
|------------+--------------------------|
| 12.3JEB | All 12.3JEA releases are |
| | fixed |
|------------+--------------------------|
| 12.3JK | 12.3(2)JK2 | 12.3(8)JK |
|------------+------------+-------------|
| 12.3JX | 12.3(7)JX6 | 12.3(11)JX |
|------------+------------+-------------|
| 12.3T | 12.3(4)T13 | 12.3(8)T |
|------------+------------+-------------|
| 12.3TPC | 12.3(4) | |
| | TPC11b | |
|------------+------------+-------------|
| 12.3XA | 12.3(2)XA6 | |
|------------+--------------------------|
| 12.3XB | Vulnerable; migrate to |
| | 12.3(8)T or later |
|------------+--------------------------|
| 12.3XC | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.3XD | Vulnerable; migrate to |
| | 12.3(8)T7 or later |
|------------+--------------------------|
| 12.3XE | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.3XF | Vulnerable; migrate to |
| | 12.3(11)T or later |
|------------+--------------------------|
| 12.3XG | Vulnerable; contact TAC |
|------------+--------------------------|
| 12.3XH | Vulnerable; migrate to |
| | 12.3(11)T or later |
|------------+--------------------------|
| 12.3XI | 12.3(7)XI8 | |
|------------+--------------------------|
| 12.3XJ | Vulnerable; migrate to |
| | 12.3(8)XW or later |
|------------+--------------------------|
| 12.3XK | Vulnerable; migrate to |
| | 12.3(14)T or later |
|------------+--------------------------|
| 12.3XQ | Vulnerable; migrate to |
| | 12.4(1) or later |
|------------+--------------------------|
| 12.3XR | All 12.3XR releases are |
| | fixed |
|------------+--------------------------|
| 12.3XS | All 12.3XS releases are |
| | fixed |
|------------+--------------------------|
| 12.3XU | All 12.3XU releases are |
| | fixed |
|------------+--------------------------|
| 12.3XW | All 12.3XW releases are |
| | fixed |
|------------+--------------------------|
| 12.3XX | All 12.3XX releases are |
| | fixed |
|------------+--------------------------|
| 12.3XY | All 12.3XR releases are |
| | fixed |
|------------+--------------------------|
| 12.3YA | All 12.3YA releases are |
| | fixed |
|------------+--------------------------|
| 12.3YD | All 12.3YD releases are |
| | fixed |
|------------+--------------------------|
| 12.3YF | All 12.3YF releases are |
| | fixed |
|------------+--------------------------|
| 12.3YG | All 12.3YG releases are |
| | fixed |
|------------+--------------------------|
| 12.3YH | All 12.3YH releases are |
| | fixed |
|------------+--------------------------|
| 12.3YI | All 12.3YI releases are |
| | fixed |
|------------+--------------------------|
| 12.3YJ | All 12.3YJ releases are |
| | fixed |
|------------+--------------------------|
| 12.3YK | All 12.3YK releases are |
| | fixed |
|------------+--------------------------|
| 12.3YM | All 12.3YM releases are |
| | fixed |
|------------+--------------------------|
| 12.3YQ | All 12.3YQ releases are |
| | fixed |
|------------+--------------------------|
| 12.3YS | All 12.3YS releases are |
| | fixed |
|------------+--------------------------|
| 12.3YT | All 12.3YT releases are |
| | fixed |
|------------+--------------------------|
| 12.3YU | All 12.3YU releases are |
| | fixed |
|------------+--------------------------|
| 12.3YX | All 12.3YX releases are |
| | fixed |
|------------+--------------------------|
| 12.3YZ | All 12.3YZ releases are |
| | fixed |
|------------+--------------------------|
| Affected | | |
| 12.4-Based | Rebuild | Maintenance |
| Release | | |
|---------------------------------------|
| All 12.4 releases are fixed |
+---------------------------------------+
+---------------------------------------+
| Cisco IOS XR Version | SMU ID |
|-----------------------------+---------|
| 3.2.2 for CRS-1 | AA01482 |
|-----------------------------+---------|
| 3.2.3 for CRS-1 | AA01483 |
|-----------------------------+---------|
| 3.2.4 for CRS-1 | AA01484 |
|-----------------------------+---------|
| 3.2.6 for CRS-1 | AA01727 |
|-----------------------------+---------|
| 3.3.x for CRS-1 and XR12000 | Fixed |
|-----------------------------+---------|
| 3.4.x for CRS-1 and XR12000 | 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-ip-option.shtml
IP Options Selective Drop
+------------------------
The IP Options Selective Drop feature allows Cisco routers to
mitigate the effects of IP options by dropping packets containing
them or by not processing (ignoring) IP options in a packet.
The most effective workaround is using the "drop" option of this
global configuration command: "ip options drop". This command
will drop all IP packets containing IP options that are both
destined to the router itself or transiting through the router
before they are processed, preventing exploitation locally and
downstream.
The IP Options Selective Drop feature is available beginning in Cisco
IOS software version 12.0(23)S for 12000, 12.0(32)S for 10720, and
12.3(4)T, 12.2(25)S, and 12.2(27)SBC for other hardware platforms.
Please note that deploying this command will drop legitimate packets
containing IP options as well. Protocols this may impact include RSVP
(used by Microsoft NetMeeting), MPLS TE, MPLS OAM, DVMRP, IGMPv3,
IGMPv2, and legitimate PGM.
Note: The "ignore" option of the global command "ip options ignore",
available only on the Cisco 12000 router beginning in 12.0(23)S, is
NOT a workaround for this issue.
Additional information about IP Options Selective Drop feature is
available at
http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00801d4a94.html
Transit Access Control Lists (ACLs)
+----------------------------------
Configure an interface ACL that blocks traffic of these types:
* Echo (Ping) ICMP type 8
* Timestamp ICMP type 13
* Information Request ICMP type 15
* Address Mask Request ICMP Type 17
* Protocol Independent Multicast (PIM) IP protocol 103
* Pragmatic General Multicast (PGM) IP protocol 113
* URL Rendezvous Directory (URD) TCP port 465
The Internet Control Message Protocol is an integral part of the
Transmission Control Protocol/Internet Protocol (TCP/IP) protocol
suite that is used to report error conditions and provide diagnostic
information. Filtering ICMP messages may impact this error condition
and diagnostic reporting including "ping" and Windows traceroute
which uses ICMP ping.
If the device is configured to process PIM, PGM, or URD, blocking
those packets will prevent legitimate operation of the protocols.
Since the source IP address of these packets can be easily spoofed,
the affected traffic should be blocked on all of the device's IPv4
interfaces.
The following ACL is specifically designed to block attack traffic
and should be applied to all IPv4 interfaces of the device and should
include topology-specific filters:
access-list 150 deny icmp any any echo
access-list 150 deny icmp any any information-request
access-list 150 deny icmp any any timestamp-request
access-list 150 deny icmp any any mask-request
access-list 150 deny tcp any any eq 465
access-list 150 deny 103 any any
access-list 150 deny 113 any any
access-list 150 permit ip any any
interface serial 2/0
ip access-group 150 in
These ACL statements should be deployed at the network edge as part
of a transit access list which will protect the router where the ACL
is configured as well as other devices behind it. Further information
about transit ACLs is available in the white paper "Transit Access
Control Lists: Filtering at Your Edge", available at
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801afc76.shtml
The following Cisco IOS XR ACL is specifically designed to block
attack traffic and should be applied to all IPv4 interfaces of the
device and should include topology-specific filters:
ipv4 access-list ios-xr-transit-acl
10 deny icmp any any echo
20 deny icmp any any information-request
30 deny icmp any any timestamp-request
40 deny icmp any any mask-request
50 deny tcp any any eq 465
60 deny 103 any any
70 deny 113 any any
80 permit ip any any
interface POS 0/2/0/
ipv4 access-group ios-xr-transit-acl ingress
Information about configuring access lists on Cisco IOS XR is
available at
http://www.cisco.com/en/US/products/ps5763/products_command_reference_chapter09186a00803e01ae.html
Infrastructure ACLs
+------------------
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.
Cisco IOS
+--------
access-list 150 deny icmp any INFRASTRUCTURE_ADDRESSES echo
access-list 150 deny icmp any INFRASTRUCTURE_ADDRESSES information-request
access-list 150 deny icmp any INFRASTRUCTURE_ADDRESSES timestamp-request
access-list 150 deny icmp any INFRASTRUCTURE_ADDRESSES mask-request
access-list 150 deny tcp any INFRASTRUCTURE_ADDRESSES eq 465
access-list 150 deny 103 any INFRASTRUCTURE_ADDRESSES
access-list 150 deny 113 any INFRASTRUCTURE_ADDRESSES
access-list 150 permit ip any any
interface serial 2/0
ip access-group 150 in
Cisco IOS XR
+-----------
ipv4 access-list ios-xr-infrastructure-acl
10 deny icmp any INFRASTRUCTURE_ADDRESSES echo
20 deny icmp any INFRASTRUCTURE_ADDRESSES information-request
30 deny icmp any INFRASTRUCTURE_ADDRESSES timestamp-request
40 deny icmp any INFRASTRUCTURE_ADDRESSES mask-request
50 deny tcp any INFRASTRUCTURE_ADDRESSES eq 465
60 deny 103 any INFRASTRUCTURE_ADDRESSES
70 deny 113 any INFRASTRUCTURE_ADDRESSES
80 permit ip any any
interface POS 0/2/0/2
ipv4 access-group ios-xr-infrastructure-acl ingress
The white paper entitled "Protecting Your Core: Infrastructure
Protection Access Control Lists" presents guidelines and recommended
deployment techniques for infrastructure protection access lists and
is available at
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml
Information about configuring access lists on Cisco IOS XR is
available at
http://www.cisco.com/en/US/products/ps5763/products_command_reference_chapter09186a00803e01ae.html
Receive ACLs
+-----------
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. A receive ACL is designed to protect only 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 and is available at
http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a0a5e.shtml
The following receive path ACL is designed specifically to block this
attack traffic:
access-list 101 deny icmp any any echo
access-list 101 deny icmp any any information-request
access-list 101 deny icmp any any timestamp-request
access-list 101 deny icmp any any mask-request
access-list 101 deny tcp any any eq 465
access-list 101 deny 103 any any
access-list 101 deny 113 any any
access-list 101 permit ip any any
!
ip receive access-list 101
Control Plane Policing
+---------------------
The Control Plane Policing (CoPP) feature may be used to mitigate
this vulnerability. In the following example, any packets that can
exploit the vulnerability are denied while all other IP traffic is
permitted. Because of the way routers process packets with IP
options, CoPP will be applied to attack packets destined for the
router itself and packets transiting through the router to other
destination IP addresses. This applies to all platforms except the
12000 where only attack packets destined for the router itself will
be dropped.
access-list 100 permit icmp any any echo
access-list 100 permit icmp any any information-request
access-list 100 permit icmp any any timestamp-request
access-list 100 permit icmp any any mask-request
access-list 100 permit tcp any any eq 465
access-list 100 permit 103 any any
access-list 100 permit 113 any any
access-list 100 deny ip any any
!
class-map match-all drop-options-class
match access-group 100
!
!
policy-map drop-options-policy
class drop-options-class
drop
!
control-plane
service-policy input drop-options-policy
Please note that in the 12.0S, 12.2S, and 12.2SX Cisco IOS trains,
the policy-map syntax is different:
policy-map drop-options-policy
class drop-options-class
police 32000 1500 1500 conform-action drop exceed-action drop
Because of the way routers process packets with IP options, CoPP will
be applied to attack packets destined for the router itself and
packets transiting through the router to other destination IP
addresses. In the following example, only packets with IP options
that can exploit the vulnerability and that are destined for the
router or that transit through the router are denied while all other
IP traffic is permitted.
ip access-list extended drop-affected-options
permit icmp any any echo option any-options
permit icmp any any information-request option any-options
permit icmp any any timestamp-request option any-options
permit icmp any any mask-request option any-options
permit pim any any option any-options
permit 113 any any option any-options
permit tcp any any eq 465 option any-options
deny ip any any
!
class-map match-all drop-options-class
match access-group name drop-affected-options
!
!
policy-map drop-opt-policy
class drop-options-class
drop
!
control-plane
service-policy input drop-opt-policy
Please note that in the 12.2S Cisco IOS train, the policy-map syntax
is different:
policy-map drop-opt-policy
class drop-options-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.
ACL support for filtering IP options requires named ACLs. ACL support
for filtering IP options is not available in 12.0S or 12.2SX.
Please note that PGM packets typically use the "Router Alert" Option,
and dropping PGM packets with IP options will affect legitimate PGM
packets.
In the above CoPP examples, 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.
Additional information on the configuration and use of the CoPP
feature can be found at
http://www.cisco.com/en/US/products/ps6642/products_white_paper0900aecd804fa16a.shtml
and
http://www.cisco.com/en/US/products/sw/iosswrel/ps1838/products_feature_guide09186a008052446b.html
Additional information for filtering IP Options with access lists can
be found at
http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_feature_guide09186a00801d4a7d.html
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@private" or "security-alert@private"
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@private
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 during internal testing.
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-ip-option.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@private
* first-teams@private
* bugtraq@private
* vulnwatch@private
* cisco@private
* cisco-nsp@private
* full-disclosure@private
* comp.dcom.sys.cisco@private
Future updates of this advisory, if any, will be placed on Cisco's
worldwide website, but may or may not be actively announced on
mailing lists or newsgroups. Users concerned about this problem are
encouraged to check the above URL for any updates.
Revision History
================
+---------------------------------------+
| Revision | | Initial |
| 1.0 | 2007-Jan-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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