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Cisco IOS Software Protocol Translation Vulnerability

Advisory ID: cisco-sa-20130327-pt

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130327-pt

Revision 1.1

Last Updated  2013 April 11 15:23  UTC (GMT)

For Public Release 2013 March 27 16:00  UTC (GMT)


Summary

The Cisco IOS Software Protocol Translation (PT) feature contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

Cisco has released free software updates that address this vulnerability. Workarounds that mitigate this vulnerability are available.

This advisory is available at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130327-pt

Note: The March 27, 2013, Cisco IOS Software Security Advisory bundled publication includes seven Cisco Security Advisories. All advisories address vulnerabilities in Cisco IOS Software. 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 March 2013 bundled publication.

Individual publication links are in "Cisco Event Response: Semiannual Cisco IOS Software Security Advisory Bundled Publication" at the following link:

http://www.cisco.com/web/about/security/intelligence/Cisco_ERP_mar13.html


Affected Products

This vulnerability affects a device that is running an affected version of Cisco IOS Software and has either a vulnerable protocol translation configuration or a Telnet-to-PAD protocol translation ruleset configured.

Vulnerable Products

A vulnerable protocol translation configuration occurs when one-step protocol translation is configured, and is using the default incoming connection port number (Telnet port 23).  If the one-step protocol translation incoming connection port number is configured for any ports other than the default, the device is not vulnerable.

To identify a vulnerable protocol translation configuration, log in to the device and issue the show translate command-line interface (CLI) command.  The following example shows a device configured for protocol translation with at least one incoming TCP/IP protocol translation connection configured for default incoming connection port number. If the output does not contain a translate entry that has Port 23 listed, the device is not vulnerable. The following output shows a device with a vulnerable configuration:
Terminal_Server#show translate

Translate From: TCP 192.168.0.1 Port 23
          To:   X25 1234
          0/0 users active, 0 peak, 0 total, 0 failures Translate From: TCP 192.168.100.25 Port 1025
          To:   X25 1235
          0/0 users active, 0 peak, 0 total, 0 failures
Terminal_Server#
The following shows a device with a non vulnerable configuration:
Terminal_Server#show translate

Translate From: TCP 192.168.0.1 Port 1025
          To:   X25 1234
          0/0 users active, 0 peak, 0 total, 0 failures Translate From: TCP 192.168.100.25 Port 1026
          To:   X25 1235
          0/0 users active, 0 peak, 0 total, 0 failures
Terminal_Server#
To determine whether a Telnet-to-PAD protocol translation ruleset is configured, log in to the device and issue the show running-config CLI command. If the output contains the configuration command translate use telnet <ip address> and has a defined ruleset with the telnet to pad command, the device is vulnerable. The following example shows a vulnerable Telnet-to-PAD protocol translation ruleset configured: 
Terminal_Server#show running-config | begin use telnet
translate use telnet 192.168.0.1
translate ruleset example_ruleset from telnet to pad
 description *** example translation ruleset ***
 match source-addr 192.168.100.1
 set pad dest-addr 4321 <rest of output removed for brevity>
Terminal_Server#

To 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 have been confirmed not vulnerable:
  • Cisco IOS XE Software
  • Cisco IOS XR Software
  • Cisco NX-OS Software
No other Cisco products are currently known to be affected by this vulnerability.

Details

Cisco IOS Software contains a vulnerability that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition.

The vulnerability is due to insufficient validation of TCP connection information when a vulnerable protocol translation configuration in the affected software is in use. An attacker could exploit this vulnerability by trying to connect to the affected protocol translation resource on the affected device. An exploit could allow the attacker to cause a reload of the affected device.

A TCP three-way handshake is not required to exploit this vulnerability.  Transit traffic will not trigger this vulnerability.

This vulnerability has been documented in Cisco bug ID CSCtz35999 (registered customers only) and has been assigned the Common Vulnerabilities and Exposures (CVE) ID CVE-2013-1147.

Vulnerability Scoring Details

Cisco has scored the vulnerability in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this security advisory is in accordance with CVSS version 2.0.

CVSS is a standards-based scoring method that conveys vulnerability severity and helps organizations determine the urgency and priority of a response.

Cisco has provided a base and temporal score. Customers can also compute environmental scores that help determine the impact of the vulnerability in their own networks.

Cisco has provided additional information regarding CVSS at the following link:

http://www.cisco.com/web/about/security/intelligence/cvss-qandas.html

Cisco has also provided a CVSS calculator to compute the environmental impact for individual networks at the following link:

http://intellishield.cisco.com/security/alertmanager/cvss

CSCtz35999 - Cisco IOS Software Protocol Translation Vulnerability

Calculate the environmental score of CSCtz35999

CVSS Base Score - 7.8

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

None

None

None

Complete

CVSS Temporal Score - 6.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed


Impact

Successful exploitation of the vulnerability may cause the affected device to reload. Continued exploitation will result in a sustained DoS attack.

Software Versions and Fixes

When considering software upgrades, customers are advised to consult the Cisco Security Advisories, Responses, and Notices 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 March 2013 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 Intelligence Operations (SIO) portal at http://tools.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 March 2013 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 March 2013 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 March 2013 Bundled Publication
12.3 Not vulnerable
Not vulnerable
12.3B Not vulnerable
Not vulnerable
12.3BC Not vulnerable
Not vulnerable
12.3BW Not vulnerable
Not vulnerable
12.3JA Not vulnerable
Not vulnerable
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 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 15.0M *
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 15.0M *
12.3JL Not vulnerable
Not vulnerable
12.3JX Not vulnerable
Not vulnerable
12.3T Vulnerable; First fixed in Release 15.0M *
Releases up to and including 12.3(7)T12 are not vulnerable.
Vulnerable; First fixed in Release 15.0M *
Releases up to and including 12.3(2)T9 are not vulnerable.
12.3TPC Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.3XA Not vulnerable
Not vulnerable
12.3XB Not vulnerable
Not vulnerable
12.3XC Not vulnerable
Not vulnerable
12.3XD Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3XE Not vulnerable
Vulnerable; First fixed in Release 15.0M *
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 15.0M *
12.3XI Not vulnerable
Vulnerable; First fixed in Release 12.2SB
12.3XJ Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3XK Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3XL Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3XQ Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3XR Vulnerable; First fixed in Release 15.0M *
Releases up to and including 12.3(7)XR are not vulnerable.
Vulnerable; First fixed in Release 15.0M *
12.3XU Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3XW Vulnerable; migrate to any release in 12.4XN
Vulnerable; First fixed in Release 15.0M *
12.3XX Vulnerable; First fixed in Release 15.0M *
Releases up to and including 12.3(8)XX1 are not vulnerable.
Vulnerable; First fixed in Release 15.0M *
12.3XY Not vulnerable
Not vulnerable
12.3XZ Not vulnerable
Not vulnerable
12.3YD Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3YF Note: Releases prior to 12.3(11)YF1 are vulnerable; Releases 12.3(11)YF1 and later are not vulnerable.
Vulnerable; First fixed in Release 15.0M *
12.3YG Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YI Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YJ Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3YK Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YM Releases up to and including 12.3(14)YM10 are not vulnerable.
Releases 12.3(14)YM12 and later are not vulnerable. First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YQ Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.3YS Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YT Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.3YU Vulnerable; First fixed in Release 15.0M *
Releases up to and including 12.3(14)YU are not vulnerable.
Vulnerable; First fixed in Release 15.0M *
12.3YX Releases 12.3(14)YX4 and 12.3(14)YX9 are vulnerable; Releases 12.3(14)YX10 and later are not vulnerable. Migrate to any release in 12.4XN.
Vulnerable; First fixed in Release 15.0M *
12.3YZ 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.
12.3ZA Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
Affected 12.4-Based Releases First Fixed Release First Fixed Release for All Advisories in the March 2013 Bundled Publication
12.4 Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
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
12.4JAM Not vulnerable
Releases prior to 12.4(25e)JAM are vulnerable; Releases 12.4(25e)JAM and later are not vulnerable. Migrate to any release in 12.4JAN12.4(25e)JAM
12.4JAX Not vulnerable
Not vulnerable
12.4JAZ 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
Vulnerable; First fixed in Release 12.4MDB
12.4MDA Not vulnerable
Vulnerable; First fixed in Release 12.4MDB
12.4MDB Not vulnerable
12.4(24)MDB13
12.4MR Releases up to and including 12.4(12)MR1 are not vulnerable.
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4MRA 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.
12.4MRB Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4SW Releases prior to 12.4(15)SW9a are vulnerable; Releases 12.4(15)SW9a and later are not vulnerable. First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4T Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XA Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XB Releases up to and including 12.4(2)XB5 are not vulnerable.
Releases 12.4(2)XB7 and later are not vulnerable. First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XC Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XD Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XE Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XF Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.4XG Releases up to and including 12.4(9)XG1 are not vulnerable.
Releases 12.4(9)XG3 and later are not vulnerable. First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XJ Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XK Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XL Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
12.4XM Not vulnerable
Vulnerable; First fixed in Release 15.0M *
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 15.0M *
12.4XR Not vulnerable
Vulnerable; First fixed in Release 15.0M *
12.4XT Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
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 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XY Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4XZ Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
12.4YA Vulnerable; First fixed in Release 15.0M *
Vulnerable; First fixed in Release 15.0M *
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
12.4(24)YE3e
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 March 2013 Bundled Publication
15.0EB Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.0ED Not vulnerable
Not vulnerable
15.0EY Not vulnerable
Not vulnerable
15.0M 15.0(1)M10 *
15.0(1)M10 *
15.0MR 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 Availability
Vulnerable; First fixed in Release 15.1S
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SE Not vulnerable
15.0(2)SE1
15.0SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SQA Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.0SY Not vulnerable
15.0(1)SY4
15.0XA Vulnerable; First fixed in Release 15.1M
Vulnerable; First fixed in Release 15.1M
15.0XO Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Affected 15.1-Based Releases First Fixed Release First Fixed Release for All Advisories in the March 2013 Bundled Publication
15.1EY Not vulnerable
Vulnerable; First fixed in Release 15.2S
15.1GC 15.1(4)GC1
15.1(4)GC1
15.1M 15.1(4)M6
15.1(4)M6
15.1MR Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1MRA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1(3)S5
† See footnote
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.1SG Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
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; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SVA Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.1SVC Not vulnerable
Not vulnerable
15.1SY Not vulnerable
15.1(1)SY1; Available on 24-MAY-13
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 March 2013 Bundled Publication
15.2GC Vulnerable; migrate to any release in 15.4T
Vulnerable; migrate to any release in 15.4T
15.2GCA Vulnerable; migrate to any release in 15.4T
Vulnerable; migrate to any release in 15.4T
15.2JA 15.2(2)JA1
15.2(4)JA; Available on 29-APR-13
15.2(2)JA
15.2JAX Not vulnerable
Not vulnerable
15.2JB Not vulnerable
Not vulnerable
15.2JN Not vulnerable
Not vulnerable
15.2M 15.2(4)M3
15.2(4)M3
15.2S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability

15.2(4)S2 Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.2SA Not vulnerable
15.2(2)SA
15.2SNG Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.2SNH Not vulnerable
Vulnerable; contact your support organization per the instructions in Obtaining Fixed Software section of this advisory.
15.2SNI Not vulnerable
Not vulnerable
15.2T 15.2(1)T4; Available on 03-MAY-13

15.2(2)T3

15.2(3)T3
15.2(1)T4; Available on 03-MAY-13
15.2(2)T3
15.2(3)T3
Affected 15.3-Based Releases First Fixed Release First Fixed Release for All Advisories in the March 2013 Bundled Publication
15.3S Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
Not vulnerable
Cisco IOS XE devices: Please see Cisco IOS XE Software Availability
15.3T 15.3(1)T1; Available on 29-MAR-13
15.3(2)T; Available on 29-MAR-13
15.3(1)T1; Available on 29-MAR-1315.3(2)T; Available on 29-MAR-13

* Cisco IOS Software Release 15.0M will reach End of Software Maintenance on April 1, 2013, and no additional rebuilds will occur. Please review the End-of-Life Notice for additional information. Customers are advised to consider migrating to Cisco IOS Software Release 15.1M.

† For Cisco 7600 Series Routers, the first fixed release for all Cisco Security Advisories in the March 2013 bundled publication is Cisco IOS Software Release 15.1(3)S5. For Cisco 7200 and 7300 Series Routers, the first fixed release for all advisories in the March 2013 bundled publication is Cisco IOS Software Release 15.1(3)S5a, which will be available on April 15, 2013.

Cisco 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.

Workarounds

The following workarounds are available to mitigate this vulnerability:

Change the Incoming Connection Default Port Number

For devices that are configured with one-step protocol translation with the default incoming connection port number, an administrator can change the default incoming connection port number to be any suitable value other than port 23.  The following example shows changing the default incoming connection port number:
Original vulnerable configuration:
translate tcp 192.168.0.3 x25 1234
Configuration with default incoming connection port number changed:
translate tcp 192.168.0.3 port 1025 x25 1234

Skip Ports in Ruleset

When using rulesets ignore ports 514 and 544:
translate ruleset example_ruleset from telnet to pad
description *** example translation using a ruleset ***
match source-addr 192.168.0.1 set pad dest-addr 1234
skip dest-port 514
skip dest-port 544

Infrastructure Access Control Lists

Although it is often difficult to block traffic transiting the network, it is possible to identify traffic that should never be allowed to target infrastructure devices and block that traffic at the network border. Infrastructure access control lists (iACLs) 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 following ACL example should be included as part of the deployed infrastructure access-list, which will protect all devices with IP addresses in the configured protocol translation incoming IP address range.

A sample access list for devices running Cisco IOS follows:

!--- Deny protocol translation services packets with source of 514|544.

access-list 150 deny  tcp any CONFIGURED_PROTOCOL_TRANSLATION_ADDRESSES MASK eq 514
access-list 150 deny  tcp any CONFIGURED_PROTOCOL_TRANSLATION_ADDRESSES MASK eq 544

!--- Permit all other traffic to transit the device.

access-list 150 permit IP any any

interface serial 2/0

  ip access-group 150 in

The white paper "Protecting Your Core: Infrastructure Protection Access Control Lists" presents guidelines and recommended deployment techniques for infrastructure protection access lists. This white paper is at http://www.cisco.com/en/US/tech/tk648/tk361/technologies_white_paper09186a00801a1a55.shtml.

Additional mitigations that can be deployed on Cisco devices within the network are available in the companion document "Identifying and Mitigating Exploitation of the Cisco IOS Software Protocol Translation Vulnerability," which is available at http://tools.cisco.com/security/center/viewAMBAlert.x?alertId=28001.

Obtaining Fixed Software

Cisco has released free software updates that address the vulnerability described in this advisory. Prior to deploying software, customers are advised to consult their maintenance providers or check the software for feature set compatibility and known issues that are specific to their environments.

Customers may only install and expect support for feature sets they have purchased. By installing, downloading, accessing, or otherwise using such software upgrades, customers agree to follow the terms of the Cisco software license at http://www.cisco.com/en/US/docs/general/warranty/English/EU1KEN_.html.

Customers with Service Contracts

Customers with contracts should obtain upgraded software through their regular update channels. For most customers, upgrades should be obtained through the Software Navigator on Cisco.com at http://www.cisco.com/cisco/software/navigator.html.

Customers using Third Party Support Organizations

Customers with Cisco products that are provided or maintained through prior or existing agreements with third-party support organizations, such as Cisco Partners, authorized resellers, or service providers, should contact that organization for assistance with the appropriate course of action.

The effectiveness of any workaround or fix depends on specific customer situations, such as product mix, network topology, traffic behavior, and organizational mission. Because of the variety of affected products and releases, customers should consult their service providers or support organizations to ensure that any applied workaround or fix is the most appropriate in the intended network before it is deployed.

Customers without Service Contracts

Customers who purchase directly from Cisco but do not hold a Cisco service contract and customers who make purchases through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should obtain upgrades by contacting the Cisco Technical Assistance Center (TAC):

  • +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

Customers should have the product serial number available and be prepared to provide the URL of this advisory as evidence of entitlement to a free upgrade. Customers without service contracts should request free upgrades through the TAC.

Refer to Cisco Worldwide Contacts at http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including localized telephone numbers, instructions, and e-mail addresses for support in various languages.

Exploitation and Public Announcements

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 service requests.

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 Security Intelligence Operations at the following link:

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20130327-pt

Additionally, a text version of this advisory is clear signed with the Cisco PSIRT PGP key and circulated among the following e-mail addresses:

  • cust-security-announce@cisco.com
  • first-bulletins@lists.first.org
  • bugtraq@securityfocus.com
  • vulnwatch@vulnwatch.org
  • cisco@spot.colorado.edu
  • cisco-nsp@puck.nether.net
  • full-disclosure@lists.grok.org.uk

Future updates of this advisory, if any, will reside on Cisco.com but may not be announced on mailing lists. Users can monitor this advisory's URL for any updates.


Revision History

Revision 1.1 2013-April-11 Updated data for 15.0EY in bundle first fixed column.
Revision 1.0 2013-March-27 Initial public release.

Cisco Security Procedures

Complete information about reporting security vulnerabilities in Cisco products, obtaining assistance with security incidents, and registering to receive security information from Cisco is available on Cisco.com at http://www.cisco.com/web/about/security/psirt/security_vulnerability_policy.html. This web page includes instructions for press inquiries regarding Cisco Security Advisories. All Cisco Security Advisories are available at http://www.cisco.com/go/psirt.