Summary

• A vulnerability in the local management (local-mgmt) CLI of Cisco UCS Manager Software could allow an authenticated, local attacker to cause a denial of service (DoS) condition on an affected device.

  The vulnerability is due to improper handling of CLI command parameters. An attacker could exploit this vulnerability by executing specific commands on the local-mgmt CLI on an affected device. A successful exploit could allow the attacker to cause internal system processes to fail to terminate properly, which could result in a buildup of stuck processes and lead to slowness in accessing the UCS Manager CLI and web UI. A sustained attack may result in a restart of internal UCS Manager processes and a temporary loss of access to the UCS Manager CLI and web UI.

  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-ucs-cli-dos-GQUxCnTe

Affected Products

• Vulnerable Products

  At the time of publication, this vulnerability affected Cisco UCS 6400 Series Fabric Interconnects if they were running a vulnerable release of Cisco UCS Manager Software.

  For information about which Cisco software releases were vulnerable at the time of publication, see the Fixed Software section of this advisory. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  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 confirmed that this vulnerability does not affect the following Cisco products:

  • Firepower 1000 Series
  • Firepower 2100 Series
  • Firepower 4100 Series
  • Firepower 9300 Security Appliances
  • MDS 9000 Series Multilayer Switches
  • Nexus 1000 Virtual Edge for VMware vSphere
  • Nexus 1000V Switch for Microsoft Hyper-V
  • Nexus 1000V Switch for VMware vSphere
  • Nexus 3000 Series Switches
  • Nexus 5500 Platform Switches
  • Nexus 5600 Platform Switches
  • Nexus 6000 Series Switches
  • Nexus 7000 Series Switches
  • Nexus 9000 Series Fabric Switches in Application Centric Infrastructure (ACI) mode
  • Nexus 9000 Series Switches in standalone NX-OS mode
  • UCS 6200 Series Fabric Interconnects
  • UCS 6300 Series Fabric Interconnects

Indicators of Compromise

• Exploitation of this vulnerability can result in a buildup of stuck ucssh processes that were not terminated correctly. To see the list of ucssh processes, use the show processes | include ucssh command on the local-mgmt CLI, as shown in the following example:

  UCS-FI-A(local-mgmt)#  show processes | include ucssh
  18795 root      20   0  160232  39056   7412 R  3.7  0.1 0:17.98 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  19390 root      20   0  160228  39600   7960 R  3.7  0.1 0:14.82 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  20838 root      20   0  160232  39600   7412 R  3.7  0.1 0:12.21 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  21923 root      20   0  160228  39600   7960 R  3.7  0.1 0:10.33 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  13744 root      20   0  160232  39056   7412 R  3.5  0.1 0:25.62 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  14990 root      20   0  160228  39600   7960 R  3.5  0.1 0:23.49 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  16234 root      20   0  160232  39600   7412 R  3.5  0.1 0:21.73 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  17436 root      20   0  160232  39056   7960 R  3.5  0.1 0:19.03 /isan/bin/ucssh --ucs-local-mgmt -t 30 -p admin
  .
  .
  .

  
  

Workarounds

• There are no workarounds that address this vulnerability.

Fixed Software

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

  Cisco UCS Software

  At the time of publication, the release information in the following table(s) was accurate. See the Details section in the bug ID(s) at the top of this advisory for the most complete and current information.

  The left column lists Cisco software releases, and the right column indicates whether a release was affected by the vulnerability described in this advisory and which release included the fix for this vulnerability.

  UCS 6400 Series Fabric Interconnects

  Cisco UCS Software Release	First Fixed Release for This Vulnerability
  4.0	4.0(4i)
  4.1	Not vulnerable

  
  

  Additional Resources

  For help determining the best Cisco NX-OS Software release for a Cisco Nexus Switch, see 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 Switches
  Cisco Nexus 5500 Platform Switches
  Cisco Nexus 5600 Platform Switches
  Cisco Nexus 6000 Series Switches
  Cisco Nexus 7000 Series Switches
  Cisco Nexus 9000 Series Switches
  Cisco Nexus 9000 Series ACI-Mode Switches

  To determine the best release for Cisco UCS Software, see 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

• This vulnerability was found by Art Kalmykov of Cisco during internal security testing.

URL

• https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-cli-dos-GQUxCnTe

Revision History

• Version	Description	Section	Status	Date
  1.0	Initial public release.	-	Final	2020-AUG-26

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