Cisco Security Advisory
Cisco IOS Software Secure Copy Privilege Escalation Vulnerability
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AV:N/AC:L/Au:S/C:C/I:C/A:C/E:F/RL:OF/RC:C
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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 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: https://sec.cloudapps.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:
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Cisco IOS cTCP Denial of Service Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-ctcp
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Cisco IOS Software Multiple Features IP Sockets Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-ip
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Cisco IOS Software Mobile IP and Mobile IPv6 Vulnerabilities
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-mobileip
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Cisco IOS Software Secure Copy Privilege Escalation
Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-scp
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Cisco IOS Software Session Initiation Protocol Denial of Service
Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-sip
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Cisco IOS Software Multiple Features Crafted TCP Sequence
Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-tcp
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Cisco IOS Software Multiple Features Crafted UDP Packet
Vulnerability
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-udp
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Cisco IOS Software WebVPN and SSLVPN Vulnerabilities
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20090325-webvpn
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Cisco IOS cTCP Denial of Service Vulnerability
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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
! username view 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.
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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
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.
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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.
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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
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; migrate to any release in 12.2SEG
12.2(44)SE6
Vulnerable; first fixed in 12.2SE
12.2(44)SE6
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.2SRC
12.2(33)SRC4; Available on 18-MAY-2009
Vulnerable; first fixed in 12.2SRC
12.2(33)SRC4; Available on 18-MAY-2009
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
12.2(33)SB4
12.2(33)SB4
Not Vulnerable
Vulnerable; first fixed in 12.2SCB
12.2(33)SCB1
12.2(33)SCB1
12.2(33)SCB1
12.2(50)SE
12.2(44)SE6
12.2(44)SE6
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
12.2(52)SG; Available on 15-MAY-2009
12.2(52)SG; Available on 15-MAY-2009
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; contact TAC
Not Vulnerable
Vulnerable; first fixed in 12.2SRC
12.2(33)SRC4; Available on 18-MAY-2009
12.2(33)SRB5a; Available on 3-April-2009
12.2(33)SRC4; Available on 18-MAY-2009
12.2(33)SRC4; Available on 18-MAY-2009
12.2(33)SRD1
12.2(33)SRD1
Vulnerable; contact TAC
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
12.2(33)SXI1
12.2(33)SXI1
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; first fixed in 12.2SRC
12.2(33)SB4
12.2(33)SRD1
12.2(33)SRC4; Available on 18-MAY-2009
Vulnerable; first fixed in 12.2SRD
12.2(33)SRD1
12.2(33)SRC4; Available on 18-MAY-2009
12.2(33)XNB3
12.2(33)XNB3
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Affected 12.3-Based Releases
First Fixed Release
Recommended Release
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Not Vulnerable
Vulnerable; contact TAC
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Not Vulnerable
Vulnerable; contact TAC
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Not Vulnerable
Vulnerable; contact TAC
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.2SB
12.2(33)SB4
Vulnerable; first fixed in 12.3YX
12.3(14)YX14
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4
12.4(18e)
12.4(23a); Available on 05-JUN-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.3YX
12.3(14)YX14
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Not Vulnerable
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.3YX
12.3(14)YX14
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
12.3(14)YM13
12.3(14)YM13
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
12.3(14)YX14
12.3(14)YX14
Vulnerable; contact TAC
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(18e)
12.4(23a); Available on 05-JUN-2009
12.4(18e)
12.4(23a); Available on 05-JUN-2009
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
Vulnerable; contact TAC
12.4(11)MD7
12.4(11)MD7
12.4(19)MR2
12.4(19)MR2
Vulnerable; contact TAC
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
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
12.4(4)XD12; Available on 27-MAR-2009
12.4(4)XD12; Available on 27-MAR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
12.4(20)T2
12.4(22)T1
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Releases prior to 12.4(15)XL4 are vulnerable, release 12.4(15)XL4 and later are not vulnerable;
12.4(15)XL4
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; contact TAC
Vulnerable; contact TAC
12.4(15)XQ2
12.4(15)XQ2
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
Vulnerable; contact TAC
12.4(11)XW10
12.4(11)XW10
Vulnerable; first fixed in 12.4T
12.4(22)T1
12.4(15)T9; Available on 29-APR-2009
12.4(15)XZ2
12.4(15)XZ2
12.4(20)YA2
12.4(20)YA3
Not Vulnerable
Not Vulnerable
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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.
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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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Show Less
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
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