Guest

Product Support

Cisco IOS Software Secure Copy Privilege Escalation Vulnerability

Advisory ID: cisco-sa-20090325-scp

http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-scp

Revision 1.3

For Public Release 2009 March 25 16:00  UTC (GMT)


Summary

The server side of the Secure Copy (SCP) implementation in Cisco IOS software contains a vulnerability that could allow authenticated users with an attached command-line interface (CLI) view to transfer files to and from a Cisco IOS device that is configured to be an SCP server, regardless of what users are authorized to do, per the CLI view configuration. This vulnerability could allow valid users to retrieve or write to any file on the device's file system, including the device's saved configuration and Cisco IOS image files, even if the CLI view attached to the user does not allow it. This configuration file may include passwords or other sensitive information.

The Cisco IOS SCP server is an optional service that is disabled by default. CLI views are a fundamental component of the Cisco IOS Role-Based CLI Access feature, which is also disabled by default. Devices that are not specifically configured to enable the Cisco IOS SCP server, or that are configured to use it but do not use role-based CLI access, are not affected by this vulnerability.

This vulnerability does not apply to the Cisco IOS SCP client feature.

Cisco has released free software updates that address this vulnerability.

There are no workarounds available for this vulnerability apart from disabling either the SCP server or the CLI view feature if these services are not required by administrators.

This advisory is posted at the following link: http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-scp.

Note: The March 25, 2009, Cisco IOS Security Advisory bundled publication includes eight Security Advisories. All of the advisories address vulnerabilities in Cisco IOS Software. Each advisory lists the releases that correct the vulnerability or vulnerabilities in the advisory.

Individual publication links are listed below:

Affected Products

Vulnerable Products

Cisco devices running an affected Cisco IOS software release, configured to offer SCP server functionality, and configured to use role-based ACL access are affected by this issue.

A device running a vulnerable Cisco IOS software release is affected if its configuration is similar to the following:

parser view <view name>
 <Definition of the CLI view>
!
username <user ID> view <view name> secret <some secret>
!
ip scp server enable

In the above configuration snippet, the parser view command defines a view that specifies what commands users in that view can execute. The username command defines a local user and attaches, via the view keyword, the previously defined view to the user. And finally, the ip scp server enable command enables the Cisco IOS SCP server.

The absence of the username command does not guarantee that the device's configuration is not affected by this vulnerability because the name of a CLI view can be supplied by means of an Authentication, Authorization, and Accounting (AAA) server by using the cli-view-name attribute.

Note: The CLI view attached to a user can be supplied by a AAA server. When inspecting a device's configuration to determine if it is affected by this vulnerability it is better to check if the SCP service is enabled (ip scp server enabled command) and whether there are any CLI views defined (parser view command).

The Cisco IOS SCP server and role-based CLI access features are disabled by default.

The SCP server functionality is only available on encryption-capable images. Encryption-capable images are those that contain either a "k8" or "k9" in the image name, for example, "C7200-ADVSECURITYK9-M". Devices that do not run encryption-capable images are not vulnerable. If a device is running an encryption-capable image, the presence in the configuration of the ip scp server enable command, the existence of CLI views (parser view command), and whether there are users (local or remote) attached to these views will determine if the device is affected.

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 12.3(26) with an installed image name of C2500-IS-L:

Router#show version
Cisco Internetwork Operating System Software
IOS (tm) 2500 Software (C2500-IS-L), Version 12.3(26), RELEASE SOFTWARE (fc2)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by cisco Systems, Inc.
Compiled Mon 17-Mar-08 14:39 by dchih

!--- output truncated

The following example identifies a Cisco product that is running Cisco IOS Software Release 12.4(20)T with an installed image name of C1841-ADVENTERPRISEK9-M:

Router#show version
Cisco IOS Software, 1841 Software (C1841-ADVENTERPRISEK9-M), Version 12.4(20)T, RELEASE SOFTWARE (fc3)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2008 by Cisco Systems, Inc.
Compiled Thu 10-Jul-08 20:25 by prod_rel_team

!--- output truncated

Additional information about Cisco IOS Software release naming conventions is available in "White Paper: Cisco IOS Reference Guide" at the following link: http://www.cisco.com/warp/public/620/1.html.

Cisco IOS XE Software is also affected by this vulnerability.

Products Confirmed Not Vulnerable

Cisco devices that do not run Cisco IOS software are not affected.

Cisco IOS devices that do not have the SCP server feature enabled, or that make use of the feature but do not have the role-based CLI feature enabled, are not affected.

Cisco IOS XR Software is not affected.

No other Cisco products are currently known to be affected by this vulnerability.

Details

SCP is a protocol similar to the Remote Copy (RCP) protocol, which allows the transfer of files between systems. The main difference between SCP and RCP is that in SCP, all aspects of the file transfer session, including authentication, occur in encrypted form, which makes SCP a more secure alternative than RCP. SCP relies on the Secure Shell (SSH) protocol, which uses TCP port 22 by default.

The Role-Based CLI Access feature allows the network administrator to define "views". Views are sets of operational commands and configuration capabilities that provide selective or partial access to Cisco IOS software EXEC and configuration (Config) mode commands. Views restrict user access to Cisco IOS command-line interface (CLI) and configuration information; that is, a view can define what commands are accepted and what configuration information is visible. For more information about the Role-Based CLI Access feature, reference http://www.cisco.com/en/US/docs/ios/12_3t/12_3t7/feature/guide/gtclivws.html.

The server side of the SCP implementation in Cisco IOS software contains a vulnerability that allows authenticated users with an attached command-line interface (CLI) view to transfer files to and from a Cisco IOS device that is configured to be a SCP server, regardless of what users are authorized to do, per the CLI view configuration. This vulnerability could allow authenticated users to retrieve or write to any file on the device's file system, including the device's saved configuration and Cisco IOS image files. This configuration file may include passwords or other sensitive information.

In the affected configuration presented in the Affected Products section, users confined to a CLI view can elevate their privileges by using SCP to write to the device's configuration. Note that a view can be attached to a user when defining the user in the local database (via the username <user name> view ... command), or by passing the attribute cli-view-name from an AAA server.

This vulnerability does not allow for authentication bypass; login credentials are verified and access is only granted if a valid username and password is provided. This vulnerability may cause authorization to be bypassed.

This vulnerability is documented in the Cisco Bug ID CSCsv38166 ( registered customers only) and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2009-0637.

Vulnerability Scoring Details

Cisco has provided scores for the vulnerabilities in this advisory based on the Common Vulnerability Scoring System (CVSS). The CVSS scoring in this Security Advisory is done in accordance with CVSS version 2.0.

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

Cisco has provided a base and temporal score. Customers can then compute environmental scores to assist in determining the impact of the vulnerability in individual networks.

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.

CSCsv38166 - SCP + views (role-based CLI) allows privilege escalation

Calculate the environmental score of CSCsv38166

CVSS Base Score - 9.0

Access Vector

Access Complexity

Authentication

Confidentiality Impact

Integrity Impact

Availability Impact

Network

Low

Single

Complete

Complete

Complete

CVSS Temporal Score - 7.4

Exploitability

Remediation Level

Report Confidence

Functional

Official-Fix

Confirmed

Impact

Successful exploitation of the vulnerability described in this advisory may allow valid but unauthorized users to retrieve or write to any file on the device's file system, including the device's saved configuration and Cisco IOS image files. This configuration file may include passwords or other sensitive information.

Software Versions 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) names a Cisco IOS release train. If a given release train is vulnerable, then the earliest possible releases that contain the fix (along with the anticipated date of availability for each, if applicable) are listed in the "First Fixed Release" column of the table. The "Recommended Release" column indicates the releases which have fixes for all the published vulnerabilities at the time of this Advisory. 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. Cisco recommends upgrading to a release equal to or later than the release in the "Recommended Releases" column of the table.

Major Release

Availability of Repaired Releases

Affected 12.0-Based Releases

First Fixed Release

Recommended Release

There are no affected 12.0 based releases

Affected 12.1-Based Releases

First Fixed Release

Recommended Release

There are no affected 12.1 based releases

Affected 12.2-Based Releases

First Fixed Release

Recommended Release

12.2

Not Vulnerable

 

12.2B

Not Vulnerable

 

12.2BC

Not Vulnerable

 

12.2BW

Not Vulnerable

 

12.2BX

Not Vulnerable

 

12.2BY

Not Vulnerable

 

12.2BZ

Not Vulnerable

 

12.2CX

Not Vulnerable

 

12.2CY

Not Vulnerable

 

12.2CZ

Not Vulnerable

 

12.2DA

Not Vulnerable

 

12.2DD

Not Vulnerable

 

12.2DX

Not Vulnerable

 

12.2EW

Not Vulnerable

 

12.2EWA

Not Vulnerable

 

12.2EX

Vulnerable; migrate to any release in 12.2SEG

12.2(44)SE6

12.2EY

Vulnerable; first fixed in 12.2SE

12.2(44)SE6

12.2EZ

Not Vulnerable

 

12.2FX

Not Vulnerable

 

12.2FY

Not Vulnerable

 

12.2FZ

Not Vulnerable

 

12.2IRA

Vulnerable; first fixed in 12.2SRC

12.2(33)SRC4; Available on 18-MAY-2009

12.2IRB

Vulnerable; first fixed in 12.2SRC

12.2(33)SRC4; Available on 18-MAY-2009

12.2IXA

Not Vulnerable

 

12.2IXB

Not Vulnerable

 

12.2IXC

Not Vulnerable

 

12.2IXD

Not Vulnerable

 

12.2IXE

Not Vulnerable

 

12.2IXF

Not Vulnerable

 

12.2IXG

Not Vulnerable

 

12.2JA

Not Vulnerable

 

12.2JK

Not Vulnerable

 

12.2MB

Not Vulnerable

 

12.2MC

Not Vulnerable

 

12.2S

Not Vulnerable

 

12.2SB

12.2(33)SB4

12.2(33)SB4

12.2SBC

Not Vulnerable

 

12.2SCA

Vulnerable; first fixed in 12.2SCB

12.2(33)SCB1

12.2SCB

12.2(33)SCB1

12.2(33)SCB1

12.2SE

12.2(50)SE

12.2(44)SE6

12.2(44)SE6

12.2SEA

Not Vulnerable

 

12.2SEB

Not Vulnerable

 

12.2SEC

Not Vulnerable

 

12.2SED

Not Vulnerable

 

12.2SEE

Not Vulnerable

 

12.2SEF

Not Vulnerable

 

12.2SEG

Not Vulnerable

 

12.2SG

12.2(52)SG; Available on 15-MAY-2009

12.2(52)SG; Available on 15-MAY-2009

12.2SGA

Not Vulnerable

 

12.2SL

Not Vulnerable

 

12.2SM

Not Vulnerable

 

12.2SO

Not Vulnerable

 

12.2SQ

Vulnerable; contact TAC

 

12.2SRA

Not Vulnerable

 

12.2SRB

Vulnerable; first fixed in 12.2SRC

12.2(33)SRC4; Available on 18-MAY-2009

12.2(33)SRB5a; Available on 3-April-2009

12.2SRC

12.2(33)SRC4; Available on 18-MAY-2009

12.2(33)SRC4; Available on 18-MAY-2009

12.2SRD

12.2(33)SRD1

12.2(33)SRD1

12.2STE

Vulnerable; contact TAC

 

12.2SU

Not Vulnerable

 

12.2SV

Not Vulnerable

 

12.2SVA

Not Vulnerable

 

12.2SVC

Not Vulnerable

 

12.2SVD

Not Vulnerable

 

12.2SVE

Not Vulnerable

 

12.2SW

Not Vulnerable

 

12.2SX

Not Vulnerable

 

12.2SXA

Not Vulnerable

 

12.2SXB

Not Vulnerable

 

12.2SXD

Not Vulnerable

 

12.2SXE

Not Vulnerable

 

12.2SXF

Not Vulnerable

 

12.2SXH

Not Vulnerable

 

12.2SXI

12.2(33)SXI1

12.2(33)SXI1

12.2SY

Not Vulnerable

 

12.2SZ

Not Vulnerable

 

12.2T

Not Vulnerable

 

12.2TPC

Not Vulnerable

 

12.2XA

Not Vulnerable

 

12.2XB

Not Vulnerable

 

12.2XC

Not Vulnerable

 

12.2XD

Not Vulnerable

 

12.2XE

Not Vulnerable

 

12.2XF

Not Vulnerable

 

12.2XG

Not Vulnerable

 

12.2XH

Not Vulnerable

 

12.2XI

Not Vulnerable

 

12.2XJ

Not Vulnerable

 

12.2XK

Not Vulnerable

 

12.2XL

Not Vulnerable

 

12.2XM

Not Vulnerable

 

12.2XN

Vulnerable; first fixed in 12.2SRC

12.2(33)SB4

12.2(33)SRD1

12.2(33)SRC4; Available on 18-MAY-2009

12.2XNA

Vulnerable; first fixed in 12.2SRD

12.2(33)SRD1

12.2(33)SRC4; Available on 18-MAY-2009

12.2XNB

12.2(33)XNB3

12.2(33)XNB3

12.2XNC

Not Vulnerable

 

12.2XO

Not Vulnerable

 

12.2XQ

Not Vulnerable

 

12.2XR

Not Vulnerable

 

12.2XS

Not Vulnerable

 

12.2XT

Not Vulnerable

 

12.2XU

Not Vulnerable

 

12.2XV

Not Vulnerable

 

12.2XW

Not Vulnerable

 

12.2YA

Not Vulnerable

 

12.2YB

Not Vulnerable

 

12.2YC

Not Vulnerable

 

12.2YD

Not Vulnerable

 

12.2YE

Not Vulnerable

 

12.2YF

Not Vulnerable

 

12.2YG

Not Vulnerable

 

12.2YH

Not Vulnerable

 

12.2YJ

Not Vulnerable

 

12.2YK

Not Vulnerable

 

12.2YL

Not Vulnerable

 

12.2YM

Not Vulnerable

 

12.2YN

Not Vulnerable

 

12.2YO

Not Vulnerable

 

12.2YP

Not Vulnerable

 

12.2YQ

Not Vulnerable

 

12.2YR

Not Vulnerable

 

12.2YS

Not Vulnerable

 

12.2YT

Not Vulnerable

 

12.2YU

Not Vulnerable

 

12.2YV

Not Vulnerable

 

12.2YW

Not Vulnerable

 

12.2YX

Not Vulnerable

 

12.2YY

Not Vulnerable

 

12.2YZ

Not Vulnerable

 

12.2ZA

Not Vulnerable

 

12.2ZB

Not Vulnerable

 

12.2ZC

Not Vulnerable

 

12.2ZD

Not Vulnerable

 

12.2ZE

Not Vulnerable

 

12.2ZF

Not Vulnerable

 

12.2ZG

Not Vulnerable

 

12.2ZH

Not Vulnerable

 

12.2ZJ

Not Vulnerable

 

12.2ZL

Not Vulnerable

 

12.2ZP

Not Vulnerable

 

12.2ZU

Not Vulnerable

 

12.2ZX

Not Vulnerable

 

12.2ZY

Not Vulnerable

 

12.2ZYA

Not Vulnerable

 

Affected 12.3-Based Releases

First Fixed Release

Recommended Release

12.3

Not Vulnerable

 

12.3B

Not Vulnerable

 

12.3BC

Not Vulnerable

 

12.3BW

Not Vulnerable

 

12.3EU

Not Vulnerable

 

12.3JA

Vulnerable; contact TAC

 

12.3JEA

Vulnerable; contact TAC

 

12.3JEB

Vulnerable; contact TAC

 

12.3JEC

Vulnerable; contact TAC

 

12.3JK

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3JL

Not Vulnerable

 

12.3JX

Vulnerable; contact TAC

 

12.3T

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3TPC

Not Vulnerable

 

12.3VA

Vulnerable; contact TAC

 

12.3XA

Not Vulnerable

 

12.3XB

Not Vulnerable

 

12.3XC

Not Vulnerable

 

12.3XD

Not Vulnerable

 

12.3XE

Not Vulnerable

 

12.3XF

Vulnerable; contact TAC

 

12.3XG

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XI

Vulnerable; first fixed in 12.2SB

12.2(33)SB4

12.3XJ

Vulnerable; first fixed in 12.3YX

12.3(14)YX14

12.3XK

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XL

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XQ

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XR

Vulnerable; first fixed in 12.4

12.4(18e)

12.4(23a); Available on 05-JUN-2009

12.3XS

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XU

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XW

Vulnerable; first fixed in 12.3YX

12.3(14)YX14

12.3XX

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XY

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3XZ

Not Vulnerable

 

12.3YA

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YD

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YF

Vulnerable; first fixed in 12.3YX

12.3(14)YX14

12.3YG

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YH

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YI

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YJ

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YK

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YM

12.3(14)YM13

12.3(14)YM13

12.3YQ

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YS

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YT

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YU

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.3YX

12.3(14)YX14

12.3(14)YX14

12.3YZ

Vulnerable; contact TAC

 

12.3ZA

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

Affected 12.4-Based Releases

First Fixed Release

Recommended Release

12.4

12.4(18e)

12.4(23a); Available on 05-JUN-2009

12.4(18e)

12.4(23a); Available on 05-JUN-2009

12.4JA

Vulnerable; contact TAC

 

12.4JDA

Vulnerable; contact TAC

 

12.4JK

Vulnerable; contact TAC

 

12.4JL

Vulnerable; contact TAC

 

12.4JMA

Vulnerable; contact TAC

 

12.4JMB

Vulnerable; contact TAC

 

12.4JX

Vulnerable; contact TAC

 

12.4MD

12.4(11)MD7

12.4(11)MD7

12.4MR

12.4(19)MR2

12.4(19)MR2

12.4SW

Vulnerable; contact TAC

 

12.4T

12.4(24)T

12.4(20)T2

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XA

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XB

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XC

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XD

12.4(4)XD12; Available on 27-MAR-2009

12.4(4)XD12; Available on 27-MAR-2009

12.4XE

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XF

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XG

12.4(20)T2

12.4(22)T1

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XJ

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XK

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XL

Releases prior to 12.4(15)XL4 are vulnerable, release 12.4(15)XL4 and later are not vulnerable;

12.4(15)XL4

12.4XM

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XN

Vulnerable; contact TAC

 

12.4XP

Vulnerable; contact TAC

 

12.4XQ

12.4(15)XQ2

12.4(15)XQ2

12.4XR

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XT

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XV

Vulnerable; contact TAC

 

12.4XW

12.4(11)XW10

12.4(11)XW10

12.4XY

Vulnerable; first fixed in 12.4T

12.4(22)T1

12.4(15)T9; Available on 29-APR-2009

12.4XZ

12.4(15)XZ2

12.4(15)XZ2

12.4YA

12.4(20)YA2

12.4(20)YA3

12.4YB

Not Vulnerable

 

12.4YD

Not Vulnerable

 

Workarounds

If the Cisco IOS SCP server functionality is not needed then the vulnerability described in this document can be mitigated by disabling the SCP server or the CLI view feature. The SCP server can be disabled by executing the following command in global configuration mode:

no ip scp server enable

If the SCP server cannot be disabled due to operational concerns, then no workarounds exist. The risk posed by this vulnerability can be mitigated by following the best practices detailed in "Cisco Guide to Harden Cisco IOS Devices" at http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a0080120f48.shtml. Please refer to the Obtaining Fixed Software section of this advisory for appropriate solutions to resolve this vulnerability.

Due to the nature of this vulnerability, networking best practices like access control lists (ACLs) and Control Plane Policing (CoPP) that restrict access to a device to certain IP addresses or subnetworks may not be effective. If access is already granted to a specific IP address or subnetwork, a user with low privileges will be able to establish an SCP session with the device, which would allow the user to exploit this vulnerability.

Obtaining Fixed Software

Cisco has released free software updates that address these vulnerabilities. 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/en/US/docs/general/warranty/English/EU1KEN_.html, or as otherwise set forth at Cisco.com Downloads at http://www.cisco.com/public/sw-center/sw-usingswc.shtml.

Do not contact 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 with Service Contracts

Customers using Third Party Support Organizations

Customers whose Cisco products 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 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 do not hold a Cisco service contract, and customers who purchase through third-party vendors but are unsuccessful in obtaining fixed software through their point of sale should acquire 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

Customers should have their product serial number available and be prepared to give the URL of this notice as evidence of entitlement to a free upgrade. Free upgrades for non-contract customers must be requested through the TAC.

Refer to http://www.cisco.com/en/US/support/tsd_cisco_worldwide_contacts.html for additional TAC contact information, including 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 reported to Cisco by Kevin Graham. Cisco would like to thank Mr. Graham for reporting this vulnerability and working with us towards coordinated disclosure of the vulnerability.

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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-scp

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

Future updates of this advisory, if any, will be placed on Cisco's worldwide website, but may or may not be actively announced on mailing lists or newsgroups. Users concerned about this problem are encouraged to check the above URL for any updates.


Revision History

Revision 1.3

2009-June-26

Removed references to the March/09 combined fixed software table.

Revision 1.2

2009-June-1

Updated expected public availability date for release 12.4(23a).

Revision 1.1

2009-May-1

Updated expected public availability date for release 12.4(23a).

Revision 1.0

2009-March-25

Initial public release

Cisco Security Procedures

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