Operating System:

[Cisco]

Published:

26 August 2021

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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.2875
  Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability
                              26 August 2021

===========================================================================

        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           UCS Manager Software
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-1592  

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy

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Cisco UCS Manager Software SSH Sessions Denial of Service Vulnerability

Priority:        Medium
Advisory ID:     cisco-sa-ucs-ssh-dos-MgvmyrQy
First Published: 2021 August 25 16:00 GMT
Version 1.0:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCvw33513
CVE Names:       CVE-2021-1592
CWEs:            CWE-664

Summary

  o A vulnerability in the way Cisco UCS Manager software handles SSH sessions
    could allow an authenticated, remote attacker to cause a denial of service
    (DoS) condition on an affected device.

    This vulnerability is due to improper resource management for established
    SSH sessions. An attacker could exploit this vulnerability by opening a
    significant number of SSH sessions on an affected device. A successful
    exploit could allow the attacker to cause a crash and restart of internal
    Cisco UCS Manager software processes and a temporary loss of access to the
    Cisco UCS Manager CLI and web UI.

    Note: The attacker must have valid user credentials to authenticate to the
    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://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy

    This advisory is part of the August 2021 Cisco FXOS and NX-OS Software
    Security Advisory Bundled Publication. For a complete list of the
    advisories and links to them, see Cisco Event Response: August 2021 Cisco
    FXOS and NX-OS Software Security Advisory Bundled Publication .

Affected Products

  o Vulnerable Products

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

    For information about which Cisco software releases are vulnerable, 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

Workarounds

  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
    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(4m)
    4.1                          4.1(3e)
    4.2                          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.

Source

  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.

Related to This Advisory

  o Cisco Event Response: August 2021 Semiannual Cisco FXOS and NX-OS Software
    Security Advisory Bundled Publication

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ucs-ssh-dos-MgvmyrQy

Revision History

  o +----------+---------------------------+----------+--------+--------------+
    | Version  |        Description        | Section  | Status |     Date     |
    +----------+---------------------------+----------+--------+--------------+
    | 1.0      | Initial public release.   | -        | Final  | 2021-AUG-25  |
    +----------+---------------------------+----------+--------+--------------+

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