Summary

• A vulnerability in the controller authorization functionality of Cisco Nexus 9000 Series ACI Mode Switch Software could allow an authenticated, local attacker to escalate standard users with root privilege on an affected device.
  
  The vulnerability is due to a misconfiguration of certain sudoers files for the bashroot component on an affected device. An attacker could exploit this vulnerability by authenticating to the affected device with a crafted user ID, which may allow temporary administrative access to escalate privileges. A successful exploit could allow the attacker to escalate privileges on an affected device.

  Cisco has released software updates that address this vulnerability. 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-20190306-aci-controller-privsec

Affected Products

• Vulnerable Products

  This vulnerability affects Cisco Nexus 9000 Series Fabric Switches in ACI mode running an affected version of Cisco NX-OS Software.

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

  Determining the Cisco NX-OS Software Release

  Administrators can determine the release of Cisco NX-OS Software running on a device by using the show version command in the device CLI. The following example identifies the 11.2(2) Release:

  nxos-n9k-aci# show version
  Cisco Nexus Operating System (NX-OS) Software
  such license is available at
  http://www.opensource.org/licenses/gpl-2.0.php and http://www.opensource.org/licenses/lgpl-2.1.php
  Software
  BIOS:      version N/A
  kickstart: version 11.2(2) [build 11.2(1.184)]
  system:    version 11.2(2) [build 11.2(1.184)]
  .
  .
  .

  Determining the Cisco Application Policy Infrastructure Controller Software Release

  There is a one-to-one mapping between the software for Cisco Application Policy Infrastructure Controller (APIC) and Cisco Nexus 9000 Series Fabric Switches in ACI mode. To determine which Cisco APIC Software release is running on a device, administrators can disregard the leftmost digit of the Cisco NX-OS Software version number. In the preceding example, the output shows Cisco NX-OS Software version 11.2(2), which maps to Cisco APIC Software Release 1.2(2).

  Products Confirmed Not Vulnerable

  Only products listed in the Vulnerable Products section of this advisory are known to be affected by this vulnerability.

  Cisco has determined that this vulnerability does not affect the following Cisco products:

  • Firepower 2100 Series Firewalls
  • Firepower 4100 Series Next-Generation Firewalls
  • Firepower 9300 Security Appliance
  • MDS 9000 Series Multilayer Director Switches
  • Nexus 1000V Switch for Microsoft Hyper-V
  • Nexus 1000V Switch for VMware vSphere
  • Nexus 2000 Series Fabric Extenders
  • Nexus 3000 Series Switches
  • Nexus 3500 Platform Switches
  • Nexus 3600 Platform Switches
  • Nexus 5000 Series Switches
  • Nexus 5500 Platform Switches
  • Nexus 5600 Platform Switches
  • Nexus 7000 Series Switches
  • Nexus 7700 Series Switches
  • Nexus 9000 Series Switches in standalone NX-OS mode
  • Nexus 9500 R-Series Line Cards and Fabric Modules
  • UCS 6200 Series Fabric Interconnects
  • UCS 6300 Series Fabric Interconnects
  • UCS 6400 Series Fabric Interconnects

Workarounds

• There are no workarounds that address this vulnerability.

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.

  Additional Resources

  For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, administrators can refer to the following Recommended Releases documents. If a security advisory recommends a later release, Cisco recommends following the advisory guidance.

  Cisco MDS Series Switches
  Cisco Nexus 1000V for VMware Switch
  Cisco Nexus 3000 Series and 3500 Series Switches
  Cisco Nexus 5000 Series Switches
  Cisco Nexus 5500 Platform Switches
  Cisco Nexus 6000 Series Switches
  Cisco Nexus 7000 Series Switches
  Cisco Nexus 9000 Series Switches
  Cisco Nexus 9000 Series ACI-Mode Switches

  For help determining the best Cisco NX-OS Software release for Cisco UCS, refer to the Recommended Releases documents in the release notes for the device.

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 Octav Opaschi with DETACK GmbH for reporting this vulnerability.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190306-aci-controller-privsec

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	—	Final	2019-March-06

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