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Cisco Security Advisory

Cisco IOS Software Smart Install Remote Code Execution Vulnerability

Critical
Advisory ID:
cisco-sa-20110928-smart-install
First Published:
2011 September 28 16:00 GMT
Last Updated:
2015 November 25 16:11 GMT
Version 1.6:
Final
Workarounds:
Yes
Cisco Bug IDs:
CSCto10165
CVE-2011-3271
CVE-2011-3271

Summary

  • A vulnerability exists in the Smart Install feature of Cisco Catalyst Switches running Cisco IOS Software that could allow an unauthenticated, remote attacker to perform remote code execution on the affected device.

    Cisco has released software updates that address this vulnerability.

    There are no workarounds available to mitigate this vulnerability other than disabling the Smart Install feature.

    This advisory is posted at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20110928-smart-install.

    Note: The September 28, 2011, Cisco IOS Software Security Advisory bundled publication includes ten Cisco Security Advisories. Nine of the advisories address vulnerabilities in Cisco IOS Software, and one advisory addresses a vulnerability in Cisco Unified Communications Manager. Each 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 vulnerabilities in the September 2011 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_sep11.html

Affected Products

  • This vulnerability only affects Cisco Catalyst Switches with the Smart Install feature enabled.

    Vulnerable Products

    Devices configured as a Smart Install client or director are affected by this vulnerability. To display Smart Install information, use the show vstack config privileged EXEC command on the Smart Install director or client. The outputs of the show commands are different when entered on the director or on the client. The following is the output of the show vstack config in a Cisco Catalyst Switch configured as a Smart Install client:

    switch#show vstack config
 Role: Client
 Vstack Director IP address: 10.1.1.163

    The following is the output of the show vstack config in a Cisco Catalyst Switch configured as a Smart Install director:

    Director# show vstack config

Role: Director
 Vstack Director IP address: 10.1.1.163
 Vstack Mode: Basic
 Vstack default management vlan: 1
 Vstack management Vlans: none
 Vstack Config file: tftp://10.1.1.100/default-config.txt
 Vstack Image file: tftp://10.1.1.100/c3750e-universalk9-tar.122-
 Join Window Details:
         Window: Open (default)
         Operation Mode: auto (default)
 Vstack Backup Details:
         Mode: On (default)
         Repository: flash:/vstack (default)

    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 the white paper Cisco IOS and NX-OS Software Reference Guide available at: http://www.cisco.com/web/about/security/intelligence/ios-ref.html.

    Products Confirmed Not Vulnerable

    Cisco IOS XR Software is not affected by this vulnerability.

    Cisco IOS XE Software is not affected by this vulnerability.

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

Details

  • Smart Install is a plug-and-play configuration and image-management feature that provides zero-touch deployment for new switches. This means that a customer can ship a switch to a location, place it in the network and power it on with no configuration required on the switch.

    A vulnerability exists in the Smart Install feature of Cisco Catalyst Switches running Cisco IOS Software that could allow an unauthenticated, remote attacker to perform remote code execution on the affected device. Smart Install uses TCP port 4786 for communication. An established TCP connection with a completed TCP three-way handshake is needed to be able to trigger this vulnerability.

    This vulnerability is documented in Cisco bug ID CSCto10165, and has been assigned Common Vulnerabilities and Exposures (CVE) ID CVE-2011-3271.

Workarounds

Fixed Software

Exploitation and Public Announcements

  • The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability described in this advisory.

    This vulnerability was discovered and reported to Cisco by Greg Jones of Digital Assurance.

Cisco Security Vulnerability Policy

  • 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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URL

Revision History

  • Version Description Section Status Date
    1.6 Updated links to related resources Multiple Final 2015-November-25

    1.5

    		Updated information in Ciso IOS Software table for Cisco IOS 12.2SXH 2012-February-17

    1.4

    		 Removed broken link in the Summary section
    		 2011-December-16

    1.3

    		 Updated Cisco Bug ID information
    		 2011-October-26

    1.2

    Update IOS Software table 12.2SE row

    2011-October-11

    1.1

    Update IOS Software table bundled publication first fixed information.

    2011-September-30

    1.0

    Initial public release.

    2011-September-28
    Show Less

Cisco Security Vulnerability Policy

  • 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.

Subscribe to Cisco Security Notifications

Related to This Advisory