Cisco Security Advisory: Crafted IP Option Vulnerability

Document ID: 81734
Advisory ID: cisco-sa-20070124-crafted-ip-option
http://www.cisco.com/warp/public/707/cisco-sa-20070124-crafted-ip-option.shtml
Revision 1.1
Last Updated 2007 January 25 1600 UTC (GMT)
For Public Release 2007 January 24 1600 UTC (GMT)

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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


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Summary
Cisco routers and switches running Cisco IOS® 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 ( registered customers only) for Cisco IOS

Cisco Bug ID CSCeh52410 ( registered customers only) 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 ( registered customers only) 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-replyor

router#show running-config

interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip information-replyBy 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-replyor

router#show running-config

interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip mask-replyBy 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-replyor

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-replyDevices 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-modeor

router#show running-config

interface FastEthernet0/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-modeThe 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 0.0.0.0Interfaces 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 systemInterfaces 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 routeror

router#show running-config

interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
ip pgm routeror

router#show running-config

interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pgm routerRouters 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 urdor

router#show running-config | include ip urd
ip urd proxyor

router#show running-config

interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-mode
ip urdor

router#show running-config

interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip pim sparse-dense-mode
ip urd proxyor

router#show running-config

interface FastEthernet1/0
ip address 192.0.2.1 255.255.255.0
ip urdRouters 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 ( registered customers only) - Crafted IP Option may cause DoS or code execution

Calculate the environmental score of CSCec71950

CVSS Base Score - 10

Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Impact Bias

Remote
Low
Not Required
Complete
Complete
Complete
Normal

CVSS Temporal Score - 8.3

Exploitability
Remediation Level
Report Confidence

Functional
Official Fix
Confirmed


CSCeh52410 ( registered customers only) - Crafted IP Option may cause ipv4-io DoS or code execution

Calculate the environmental score of CSCeh52410

CVSS Base Score - 10

Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact
Impact Bias

Remote
Low
Not Required
Complete
Complete
Complete
Normal

CVSS Temporal Score - 8.3

Exploitability
Remediation Level
Report Confidence

Functional
Official Fix
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/public/770/fn62613.shtml

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

Major Release
Availability of Repaired Releases

Affected 12.0-Based Release
Rebuild
Maintenance

12.0
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)SX11
12.0(30)SX

12.0SY
12.0(27)SY

12.0SZ
12.0(30)SZ

12.0T
Vulnerable; migrate to 12.2(37)or later

12.0W
12.0(28)W5(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 Release
Rebuild
Maintenance

12.1
Vulnerable; migrate to 12.2(37)or later

12.1AA
Vulnerable; migrate to 12.2(37)or later

12.1AX
Vulnerable; for c3750-ME, migrate to 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

12.1EO
12.1(19)EO6, available 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 Release
Rebuild
Maintenance

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

12.2DA
12.2(10)DA5

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

12.2EW
12.2(18)EW3

12.2(20)EW4
12.2(25)EW

12.2EWA
12.2(20)EWA4
12.2(25)EWA

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

12.2ZG
Vulnerable; for SOHO9x, 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 Release
Rebuild
Maintenance

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 Release
Rebuild
Maintenance

All 12.4 releases are fixed


Cisco IOS XR Version
SMU ID
Package Installation Envelopes

3.2.2 for CRS-1
AA01482
hfr-base-3.2.2.CSCeh52410.pie

3.2.3 for CRS-1
AA01483
hfr-base-3.2.3.CSCeh52410.pie

3.2.4 for CRS-1
AA01484
hfr-base-3.2.4.CSCeh52410.pie

3.2.6 for CRS-1
AA01727
hfr-base-3.2.6.CSCeh52410.pie

3.3.x for CRS-1 and XR12000
Fixed

3.4.x for CRS-1 and XR12000
Fixed




IOS XR Package Installation Envelopes (PIE) can be downloaded from: http://www.cisco.com/pcgi-bin/tablebuild.pl/iosxr-smu?sort=release ( registered customers only) . Installation instructions are included in the accompanying .txt files.

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 inThese 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 ingressInformation 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 inCisco 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 ingressThe 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 101Control 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-policyPlease 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 dropBecause 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-policyPlease 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 dropCoPP 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@cisco.com" or "security-alert@cisco.com" for software upgrades.

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

Customers using Third Party Support Organizations
Customers whose Cisco products are provided or maintained through prior or existing 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@cisco.com

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@cisco.com

first-teams@first.org

bugtraq@securityfocus.com

vulnwatch@vulnwatch.org

cisco@spot.colorado.edu

cisco-nsp@puck.nether.net

full-disclosure@lists.grok.org.uk

comp.dcom.sys.cisco@newsgate.cisco.com