Summary

• A vulnerability in the Python scripting subsystem of Cisco NX-OS Software could allow an authenticated, local attacker to escape the Python parser and gain unauthorized access to the underlying operating system of the device.
  
  The vulnerability exists due to insufficient sanitization of user-supplied parameters that are passed to certain Python functions within the scripting sandbox of the affected device. An attacker could exploit this vulnerability to escape the scripting sandbox and execute arbitrary commands on the underlying operating system with the privileges of the authenticated user.
  
  To exploit this vulnerability, an attacker must have local access and be authenticated to the targeted device with administrative or Python execution privileges. These requirements could limit the possibility of a successful exploit.
  
  There are no workarounds that address this vulnerability.
  
  This advisory is available at the following link:
  
  https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171018-ppe

Affected Products

• Vulnerable Products

  This vulnerability affects the following Cisco products if they are running Cisco NX-OS Software:
  
  

  Multilayer Director Switches
  Nexus 2000 Series Fabric Extenders
  Nexus 3000 Series Switches
  Nexus 3500 Platform Switches
  Nexus 5000 Series Switches
  Nexus 5500 Platform Switches
  Nexus 5600 Platform Switches
  Nexus 6000 Series Switches
  Nexus 7000 Series Switches
  Nexus 7700 Series Switches
  Nexus 9000 Series Switches - Standalone, NX-OS mode
  Nexus 9500 R-Series Line Cards and Fabric Modules
  

  
  For information about affected software releases, consult the Cisco bug ID(s) at the top of this advisory.

  Products Confirmed Not Vulnerable

  No other Cisco products are currently known to be affected by this vulnerability.
  
  Cisco has confirmed that this vulnerability does not affect the following Cisco products:
  
  

  Firepower 2100 Series
  Firepower 4100 Series Next-Generation Firewall
  Firepower 9300 Security Appliance
  Nexus 1000V Series Switches
  Nexus 9000 Series Fabric Switches - ACI mode
  Unified Computing System Manager
  

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

Workarounds

• There are no workarounds that address this vulnerability. However, an administrator can reduce exposure to this vulnerability by ensuring that only highly trusted users are allowed access to the Python sandbox.

Fixed Software

• For information about fixed software releases, consult the Cisco bug ID(s) at the top of this advisory.

  When considering software upgrades, customers are advised to regularly consult the advisories for Cisco products, which are available from the Cisco Security Advisories and Alerts page, 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.

  The following table lists the affected products and the associated Cisco bug ID(s):

  Affected Products	Cisco bug ID
  Nexus 3000 Series Switches	CSCve97102
  Nexus 3500 Platform Switches	CSCvf12757, CSCvf12804
  Nexus 2000 Series Fabric Extenders Nexus 5000 Series Switches Nexus 5500 Platform Switches Nexus 5600 Platform Switches Nexus 6000 Series Switches	CSCvf12815, CSCvf15198
  Nexus 7000 Series Switches Nexus 7700 Series Switches Multilayer Director Switches	CSCvb86832, CSCvd86474, CSCvd86484, CSCvd86479, CSCvd86490
  Cisco Nexus 9000 Series Switches - Standalone, NX-OS mode	CSCve97102
  Cisco Nexus 9500 R-Series Line Cards and Fabric Modules	CSCve97102

  
  

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.

Source

• Cisco would like to thank network engineer Cody Winkler for finding and reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20171018-ppe

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2017-October-18

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