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             AUSCERT External Security Bulletin Redistribution

         Cisco UCS Manager Software Local Management CLI Denial of
                           Service Vulnerability
                              27 August 2020


        AusCERT Security Bulletin Summary

Product:           Cisco UCS Manager Software
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-3504  

Original Bulletin: 

- --------------------------BEGIN INCLUDED TEXT--------------------

Cisco UCS Manager Software Local Management CLI Denial of Service Vulnerability

Priority:        Medium

Advisory ID:     cisco-sa-ucs-cli-dos-GQUxCnTe

First Published: 2020 August 26 16:00 GMT

Version 1.0:     Final

Workarounds:     No workarounds available

Cisco Bug IDs:   CSCvr91760




  o 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:

Affected Products

  o 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

  o 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


  o There are no workarounds that address this vulnerability.

Fixed Software

  o 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

    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

  o 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.


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

Cisco Security Vulnerability Policy

  o 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.


  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/

Revision History

  o +----------+---------------------------+----------+--------+--------------+
    | Version  |        Description        | Section  | Status |     Date     |
    | 1.0      | Initial public release.   | -        | Final  | 2020-AUG-26  |

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