AV:N/AC:L/Au:N/C:N/I:N/A:C/E:F/RL:OF/RC:C
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Cisco IOS Software contains a vulnerability in the Intrusion Prevention System (IPS) feature that could allow an unauthenticated, remote attacker to cause a reload of an affected device if specific Cisco IOS IPS configurations exist.
Cisco has released software updates that address this vulnerability.
Workarounds that mitigate this vulnerability are available.
This advisory is available at the following link: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20120926-ios-ips
Note: The September 26, 2012, Cisco IOS Software Security Advisory bundled publication includes nine Cisco Security Advisories. Eight of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each Cisco IOS Software Security Advisory lists the Cisco IOS Software releases that correct the vulnerability or vulnerabilities detailed in the advisory as well as the Cisco IOS Software releases that correct all Cisco IOS Software vulnerabilities in the September 2012 bundled publication.
Individual publication links are in "Cisco Event Response: Semi-Annual Cisco IOS Software Security Advisory Bundled Publication" at the following link:
http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_sep12.html
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Vulnerable Products
Devices configured with Cisco IOS IPS are affected by this vulnerability under certain Cisco IOS IPS configurations when running a vulnerable version of Cisco IOS Software.
A device will have an affected configuration if both of the following two conditions are true:
- Any of the following categories are enabled in the Cisco IOS IPS configuration:
- diag2 (in configurations)
- general_os (in os)
- general_attack (in attack)
- general_service (in other_services)
- tcp (in l2/l3/l4_protocol/ip)
- udp (in l2/l3/l4_protocol/ip)
- dns (network_services)
- advanced (in ios_ips)
- basic (in ios_ips)
- past_releases (in releases)
To determine if any of the preceding categories are enabled, log in to the device and enter the command line interface (CLI) command show ip ips configuration | begin IPS Category CLI Configuration. If any of the above categories are in the output and have the Enable field value True, then the category is enabled. The following example shows a device with the category basic enabled on the device:
Router#show ip ips configuration | begin IPS Category CLI Configuration
IPS Category CLI Configuration:
Category all:
Retire: True
Enable: False
Category ios_ips basic:
Retire: False
Enable: True
Category other_services:
Retire: True
Enable: False - If the four IPS signatures 6054:0, 6054:1, 6062:0, 6062:1 are all not compiled.
To determine if the four signatures are all not compiled log into the device and enter the CLI command show ip ips signatures | include 6054|6062. If the compiled status column (third column in the example, all of which have the Nr value), shows any value other than Y then the signature is not compiled. The following example shows a device with all four signatures not compiled on the device:
Router#show ip ips signatures | include 6054|6062
6062:1 N* Nr A LOW 0 1 0 200 30 FA N 100 S3
6062:0 N* Nr A LOW 0 1 0 200 30 FA N 100 S3
6054:1 N* Nr A LOW 0 1 0 200 30 FA N 100 S2
6054:0 N* Nr A LOW 0 1 0 200 30 FA N 100 S2To determine the Cisco IOS Software release that is running on a Cisco product, administrators can log in to the device and issue the show version command to display the system banner. The system banner confirms that the device is running Cisco IOS Software by displaying text similar to "Cisco Internetwork Operating System Software" or "Cisco IOS Software." The image name displays in parentheses, followed by "Version" and the Cisco IOS Software release name. Other Cisco devices do not have the show version command or may provide different output.
The following example identifies a Cisco product that is running Cisco IOS Software Release 15.0(1)M1 with an installed image name of C3900-UNIVERSALK9-M:
Router> show version
Cisco IOS Software, C3900 Software (C3900-UNIVERSALK9-M), Version 15.0(1)M1, RELEASE SOFTWARE (fc1)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2009 by Cisco Systems, Inc.
Compiled Wed 02-Dec-09 17:17 by prod_rel_team!--- output truncated
Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS and NX-OS Software Reference Guide" at http://www.cisco.com/web/about/security/intelligence/ios-ref.html.
Products Confirmed Not Vulnerable
The following products are not affected by this vulnerability:
- Cisco IPS 4200 Series Sensors
- Cisco IPS 4300 Series Sensors
- Cisco ASA Advanced Inspection and Prevention Security Services Module
- Cisco ASA IP Audit for Basic IPS Support
- Cisco Catalyst 6500 Series Intrusion Detection System
- Cisco IOS Software Firewall Intrusion Detection System
- Any of the following categories are enabled in the Cisco IOS IPS configuration:
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Cisco IOS Software contains a denial of service vulnerability that could allow an unauthenticated, remote attacker to cause an affected device to reload.
An attacker could exploit this vulnerability by sending legitimate DNS packets through a device with an affected Cisco IOS IPS configuration. An exploit could allow the attacker to cause a reload of the affected device.
This vulnerability has been documented in Cisco Bug ID CSCtw55976 (registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2012-3950.
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Either of the following two mitigations will prevent exploitation of the vulnerability against the device:
Enable DNS Version Request (6054/0 and 6054/1) and DNS Authors Request (6062/0 and 6062/1) signatures on the device
Enabling any of the 6054 or 6062 signatures will prevent exploitation. The following example shows all four signatures enabled:
Router#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
Router(config)#ip ips signature-definition
Router(config-sigdef)#signature 6054 0
Router(config-sigdef-sig)#status
Router(config-sigdef-sig-status)#enabled true
Router(config-sigdef-sig-status)#retired false
Router(config-sigdef-sig-status)#signature 6054 1
Router(config-sigdef-sig)#status
Router(config-sigdef-sig-status)#enabled true
Router(config-sigdef-sig-status)#retired false
Router(config-sigdef-sig-status)#signature 6062 0
Router(config-sigdef-sig)#status
Router(config-sigdef-sig-status)#enabled true
Router(config-sigdef-sig-status)#retired false
Router(config-sigdef-sig-status)#signature 6062 1
Router(config-sigdef-sig)#status
Router(config-sigdef-sig-status)#enabled true
Router(config-sigdef-sig-status)#retired false
Router(config-sigdef-sig-status)#end
Do you want to accept these changes? [confirm]
To configure a Cisco IOS IPS device not to inspect DNS traffic, attach an access list to the IPS name which denies DNS traffic. The following example shows an ACL attached to the IPS name, which instructs Cisco IOS IPS not to examine DNS packets:
Router#show running-config <! output removed for brevity !> ! ip ips name iosips list dont_inspect_dns ! ip access-list extended dont_inspect_dns
deny udp any any eq domain
deny tcp any any eq domain remark <! Include other protocols that are not required to be inspected here !>
permit ip any any
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When considering software upgrades, customers are advised to consult the Cisco Security Advisories and Responses archive at http://www.cisco.com/go/psirt and review subsequent advisories to determine exposure and a complete upgrade solution.
In all cases, customers should ensure that the devices to be upgraded contain sufficient memory and confirm that current hardware and software configurations will continue to be supported properly by the new release. If the information is not clear, customers are advised to contact the Cisco Technical Assistance Center (TAC) or their contracted maintenance providers.
Cisco IOS Software
Each row of the following Cisco IOS Software table corresponds to a Cisco IOS Software train. If a particular train is vulnerable, the earliest releases that contain the fix are listed in the First Fixed Release column. The First Fixed Release for All Advisories in the September 2012 Bundled Publication column lists the earliest possible releases that correct all the published vulnerabilities in the Cisco IOS Software Security Advisory bundled publication. Cisco recommends upgrading to the latest available release, where possible.
The Cisco IOS Software Checker allows customers to search for Cisco Security Advisories that address specific Cisco IOS Software releases. This tool is available on the Cisco Security (SIO) portal at https://sec.cloudapps.cisco.com/security/center/selectIOSVersion.x
Major Release Availability of Repaired Releases Affected 12.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication There are no affected 12.0 based releases Affected 12.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication There are no affected 12.2 based releases Affected 12.3-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication 12.3 Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3B Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3BC Not vulnerable
Not vulnerable
12.3BW Not vulnerable
Not vulnerable
12.3JA Releases prior to 12.3(4)JA2 are vulnerable; Releases 12.3(4)JA2 and later are not vulnerable. Migrate to any release in 12.4JA
Releases prior to 12.3(4)JA2 are vulnerable; Releases 12.3(4)JA2 and later are not vulnerable. Migrate to any release in 12.4JA
12.3JEA Not vulnerable
Not vulnerable
12.3JEB Not vulnerable
Not vulnerable
12.3JEC Not vulnerable
Not vulnerable
12.3JED Not vulnerable
Not vulnerable
12.3JEE Not vulnerable
Not vulnerable
12.3JK Releases prior to 12.3(8)JK1 are vulnerable; Releases 12.3(8)JK1 and later are not vulnerable. Migrate to any release in 12.3T
Releases up to and including 12.3(2)JK3 are not vulnerable. Releases 12.3(8)JK1 and later are not vulnerable. First fixed in Release 12.4
12.3JL Not vulnerable
Not vulnerable
12.3JX Not vulnerable
Not vulnerable
12.3T Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3TPC Not vulnerable
Releases up to and including 12.3(4)TPC11a are not vulnerable.
12.3VA Not vulnerable
Not vulnerable
12.3XA Not vulnerable
Releases prior to 12.3(2)XA7 are vulnerable; Releases 12.3(2)XA7 and later are not vulnerable. First fixed in Release 12.4
12.3XB Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3XC Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XD Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XE Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XF Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3XG Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XI Not vulnerable
12.3(7)XI1b
12.3XJ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3XK Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XL Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3XQ Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XR Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XU Not vulnerable
Vulnerable; First fixed in Release 12.4T
Releases up to and including 12.3(8)XU1 are not vulnerable.
12.3XW Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3XX Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XY Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3XZ Not vulnerable
Vulnerable; First fixed in Release 12.4
12.3YD Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YF Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YG Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YI Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YJ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YK Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YM Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YQ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YS Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YT Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YU Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YX Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.3YZ Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3ZA Not vulnerable
Vulnerable; First fixed in Release 12.4T
Affected 12.4-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication 12.4 Not vulnerable
12.4(25g)
12.4GC Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4JA Not vulnerable
Not vulnerable
12.4JAL Not vulnerable
Not vulnerable
12.4JAX Not vulnerable
Not vulnerable
12.4JAY Not vulnerable
Not vulnerable
12.4JDA Not vulnerable
Not vulnerable
12.4JDC Not vulnerable
Not vulnerable
12.4JDD Not vulnerable
Not vulnerable
12.4JDE Not vulnerable
Not vulnerable
12.4JHA Not vulnerable
Not vulnerable
12.4JHB Not vulnerable
Not vulnerable
12.4JHC Not vulnerable
Not vulnerable
12.4JK Not vulnerable
Not vulnerable
12.4JL Not vulnerable
Not vulnerable
12.4JX Not vulnerable
Not vulnerable
12.4JY Not vulnerable
Not vulnerable
12.4JZ Not vulnerable
Not vulnerable
12.4MD Not vulnerable
12.4(24)MD7
12.4MDA Not vulnerable
12.4(24)MDA11 for 7600-SAMI
Releases up to and including 12.4(22)MDA6 are not vulnerable.
12.4MDB Not vulnerable
12.4(24)MDB10
12.4MR Releases prior to 12.4(19)MR1 are vulnerable; Releases 12.4(19)MR1 and later are not vulnerable. Migrate to any release in 12.4MRA
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRB Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4SW Not vulnerable
Not vulnerable
12.4T 12.4(24)T8
12.4(24)T8
12.4XA Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XB Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XC Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XD Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XE Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XF Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XG Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XJ Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XK Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XL Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XM Not vulnerable
Releases up to and including 12.4(15)XM are not vulnerable. Releases 12.4(15)XM3 and later are not vulnerable. First fixed in Release 12.4T
12.4XN Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XP Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XQ Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XR Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XT Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4XV Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XW Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XY Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4XZ Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4YA Vulnerable; First fixed in Release 12.4T
Vulnerable; First fixed in Release 12.4T
12.4YB Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YD Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4YE Not vulnerable
Vulnerable; First fixed in Release 12.4T
12.4YG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
Affected 15.0-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication 15.0EX Not vulnerable
Not vulnerable
15.0EY Not vulnerable
Not vulnerable
15.0M 15.0(1)M9
15.0(1)M9
15.0MR Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0MRA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.0(1)S6
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.0SE Not vulnerable
15.0(2)SE
15.0(2)SE1; Available on 10-DEC-12
15.0SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.0(2)SG5
15.0(2)SG6; Available on 11-OCT-12
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.0SQA Not vulnerable
Not vulnerable
15.0SY Not vulnerable
15.0(1)SY2
15.0XA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.0XO Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software AvailabilityVulnerable; First fixed in Release 15.0SG
Cisco IOS XE devices: Please see Cisco IOS XE Software AvailabilityAffected 15.1-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication 15.1EY Not vulnerable
15.1(2)EY4
15.1GC Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1M 15.1(4)M5
15.1(4)M5
15.1MR Not vulnerable
15.1(3)MR
15.1S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.1(3)S3
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.1SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1(1)SG1
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SNG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SNI Not vulnerable
Vulnerable; migrate to any release in 15.2SNG
15.1SV Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1T Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.1XB Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
Affected 15.2-Based Releases First Fixed Release First Fixed Release for All Advisories in the September 2012 Cisco IOS Software Security Advisory Bundled Publication 15.2GC Releases prior to 15.2(3)GC are vulnerable; Releases 15.2(3)GC and later are not vulnerable. First fixed in Release 15.2T
Releases prior to 15.2(3)GC are vulnerable; Releases 15.2(3)GC and later are not vulnerable. First fixed in Release 15.2T
15.2JA Not vulnerable
Not Vulnerable
15.2M Not vulnerable
15.2(4)M
15.2S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.2(1)S2
15.2(2)S1
15.2(4)S
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability15.2SNG Not vulnerable
Not vulnerable
15.2T 15.2(1)T3
15.2(2)T2
15.2(3)T2; Available on 12-OCT-12
15.2(1)T3
15.2(2)T2
15.2(3)T2; Available on 12-OCT-12Cisco IOS XE Software
Cisco IOS XE Software is not affected by the vulnerability that is disclosed in this advisory.
Cisco IOS XR Software
Cisco IOS XR Software is not affected by the vulnerability that is disclosed in this advisory.
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The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
This vulnerability was discovered when handling customer support requests.
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To learn about Cisco security vulnerability disclosure policies and publications, see the Security Vulnerability Policy. This document also contains instructions for obtaining fixed software and receiving security vulnerability information from Cisco.
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Revision 1.0 2012-September-26 Initial public release
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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 is an uncontrolled copy, and may lack important information or contain factual errors. The information in this document is intended for end-users of Cisco products.