Cisco Wide Area Application Services Remote Code Execution Vulnerability

Summary

• A vulnerability in Cisco Wide Area Application Services (WAAS) software versions 5.1.1 through 5.1.1d, when configured with the SharePoint acceleration feature, could allow an unauthenticated, remote attacker to exploit a buffer overflow and cause arbitrary code execution.
  
  The vulnerability is due to incorrect buffer handling for SharePoint responses. An attacker could exploit this vulnerability by convincing a user to access a malicious SharePoint application. An exploit could allow the attacker to crash the application optimization handler and execute arbitrary code with elevated privileges on the WAAS appliance.
  
  Cisco has released software updates that address this vulnerability. This advisory is available at the following link:
  http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140521-waas

Affected Products

• Vulnerable Products

  The following products running a vulnerable version of Cisco WAAS software and configured with the SharePoint prefetch option are affected by this vulnerability:
  

  • Cisco WAAS appliances
  • Cisco Virtual WAAS (vWAAS)
  • Cisco WAAS modules

  The prefetch option is enabled by the following command accelerator http sharepoint-opt prefetch enable. This option is disabled by default.
  
  Note: Only Cisco WAAS software releases 5.1.1 through 5.1.1.d are affected by this vulnerability.
  
  To determine whether the SharePoint prefetch option has been enabled do one of the following:
  
  Check the output of sh run | include prefetch. If the command returns as shown in the following example, the prefetch option is enabled:

  waas_lab#sh run | include prefetch
  accelerator http sharepoint-opt prefetch enable

  
  Check the output of the show accelerator http command and look for the SharePoint Prefetch line. The following output example demonstrates a system that has enabled the SharePoint Accelerator:

  waas_lab#show accelerator http
  
  Accelerator    	Licensed       	Config State   	Operational State
  -----------    	--------       	------------   	-----------------
  http           	Yes            	Enabled        	Running
  
  HTTP:
     Accelerator Config Item            Mode        Value
     -----------------------            ----        ------
     Suppress Server Encoding           Default     Disabled
  [...]
     Sharepoint Prefetch                User        Enabled
  [...]

  Products Confirmed Not Vulnerable

  The following products running Cisco WAAS software are not affected by this vulnerability:

  • Cisco WAAS Express (WAASx)
  • Cisco WAAS Mobile

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

Details

• Cisco WAAS application acceleration and WAN optimization solutions accelerate the performance of any TCP-based application delivered across a WAN, providing the benefits of branch-office data consolidation and acceleration of centralized applications.
  
  A vulnerability in the SharePoint prefetch optimization code of Cisco WAAS could allow an unauthenticated, remote attacker to cause the optimization process to crash and may allow arbitrary execution code on the affected system.
  
  The vulnerability is due to a failure to properly validate certain types of requests. An attacker could exploit this vulnerability by convincing a user to connect to a malicious SharePoint installation that could supply a malformed response to a user request that is optimized by an affected device. A successful attack could allow the attacker to execute arbitrary code on the device with elevated privileges.
  
  Note: Only Cisco WAAS software that is specifically configured with SharePoint prefetch optimization is affected by this vulnerability. This option is disabled by default.
  
  This vulnerability is documented in Cisco bug ID CSCue18479 (registered customers only) and has been assigned Common Vulnerabilities and Exposure (CVE) ID CVE-2014-2196.

Workarounds

• There are no workarounds that mitigate this vulnerability.

Fixed Software

• The following table lists the recommended releases for each Cisco WAAS software major release:
  
  

  Major Releases	Recommended Release
  4.x	Not affected
  5.0.x	Not affected
  5.1.x	5.1.1e
  5.2.x	Not affected
  5.3.x	Not affected

  
  Note: Only Cisco WAAS software releases 5.1.1 through 5.1.1.d are affected by this vulnerability.
  
  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.

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.

URL

• http://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20140521-waas

Revision History

• Revision 1.0

  2014-May-21

  Initial public release.

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