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             AUSCERT External Security Bulletin Redistribution

                               ESB-2021.3319
         Cisco Small Business 220 Series Smart Switches Link Layer
                    Discovery Protocol Vulnerabilities
                              7 October 2021

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

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

Product:           Small Business 220 Series Smart Switches
Publisher:         Cisco Systems
Operating System:  Cisco
Impact/Access:     Execute Arbitrary Code/Commands -- Remote/Unauthenticated
                   Denial of Service               -- Remote/Unauthenticated
                   Reduced Security                -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2021-34780 CVE-2021-34779 CVE-2021-34778
                   CVE-2021-34777 CVE-2021-34776 CVE-2021-34775

Original Bulletin: 
   https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb220-lldp-multivuls-mVRUtQ8T

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

Cisco Small Business 220 Series Smart Switches Link Layer Discovery Protocol
Vulnerabilities

Priority:        High
Advisory ID:     cisco-sa-sb220-lldp-multivuls-mVRUtQ8T
First Published: 2021 October 6 16:00 GMT
Version 1.0:     Final
Workarounds:     No workarounds available
Cisco Bug IDs:   CSCvz29108 CSCvz29116 CSCvz29120 CSCvz29121 CSCvz29126
                 CSCvz29134
CVE Names:       CVE-2021-34775 CVE-2021-34776 CVE-2021-34777 CVE-2021-34778
                 CVE-2021-34779 CVE-2021-34780
CWEs:            CWE-120 CWE-125

Summary

  o Multiple vulnerabilities exist in the Link Layer Discovery Protocol (LLDP)
    implementation for Cisco Small Business 220 Series Smart Switches. An
    unauthenticated, adjacent attacker could perform the following:

       Execute code on the affected device or cause it to reload unexpectedly
       Cause LLDP database corruption on the affected device

    For more information about these vulnerabilities, see the Details section
    of this advisory.

    Note: LLDP is a Layer 2 protocol. To exploit these vulnerabilities, an
    attacker must be in the same broadcast domain as the affected device (Layer
    2 adjacent).

    Cisco has released firmware updates that address these vulnerabilities.
    There are no workarounds that address these vulnerabilities.

    This advisory is available at the following link:
    https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb200-lldp-multivuls-mVRUtQ8T

Affected Products

  o Vulnerable Products

    These vulnerabilities affect Cisco Small Business 220 Series Smart Switches
    if they are running a vulnerable firmware release and have the LLDP feature
    enabled.

    Note: LLDP is enabled by default on all LAN ports on Cisco Small Business
    220 Series Smart Switches.

    For information about which Cisco firmware releases are vulnerable, see the
    Fixed Software section of this advisory.

    Products Confirmed Not Vulnerable

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

Details

  o The vulnerabilities are not dependent on one another. Exploitation of one
    of the vulnerabilities is not required to exploit another vulnerability. In
    addition, a software release that is affected by one of the vulnerabilities
    may not be affected by the other vulnerabilities.

    Details about the vulnerabilities are as follows:

    CVE-2021-34779, CVE-2021-34780:
    Cisco Small Business 220 Series Smart Switches Link Layer Discovery
    Protocol Denial of Service Vulnerabilities

    Multiple vulnerabilities in the Link Layer Discovery Protocol of Cisco
    Small Business 220 Series Smart Switches could allow an unauthenticated,
    adjacent attacker to cause an affected device to reload unexpectedly.

    These vulnerabilities are due to insufficient boundary checks when
    processing LLDP messages. An attacker could exploit these vulnerabilities
    by sending a malicious LLDP packet to the targeted device. A successful
    exploit could allow the attacker to execute code on the affected device or
    cause it to reload unexpectedly, resulting in a denial of service
    condition.

    Cisco has released firmware updates that address these vulnerabilities.
    There are no workarounds that address these vulnerabilities.

    Bug ID(s): CSCvz29121 , CSCvz29126
    CVE ID: CVE-2021-34779, CVE-2021-34780
    Security Impact Rating (SIR): High
    CVSS Base Score: 8.8
    CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

    CVE-2021-34775, CVE-2021-34776, CVE-2021-34777, CVE-2021-34778:
    Cisco Small Business 220 Series Smart Switches Link Layer Discovery
    Protocol Database Corruption Vulnerabilities

    Multiple vulnerabilities in the Link Layer Discovery Protocol of Cisco
    Small Business 220 Series Smart Switches could allow an unauthenticated,
    adjacent attacker to cause LLDP memory corruption on an affected device.

    These vulnerabilities are due to missing length validation checks when
    processing LLDP messages. An attacker could exploit these vulnerabilities
    by sending a malicious LLDP packet to the targeted device. A successful
    exploit could allow the attacker to cause an out-of-bounds read of the
    valid LLDP packet data, which could allow the attacker to cause corruption
    in the internal LLDP database of the affected device.

    Cisco has released firmware updates that address these vulnerabilities.
    There are no workarounds that address these vulnerabilities.

    Bug ID(s): CSCvz29108 , CSCvz29116 , CSCvz29120 , CSCvz29134
    CVE ID: CVE-2021-34775, CVE-2021-34776, CVE-2021-34777, CVE-2021-34778
    Security Impact Rating (SIR): Medium
    CVSS Base Score: 4.3
    CVSS Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Workarounds

  o There are no workarounds that address these vulnerabilities. However,
    administrators may disable the affected feature.

    To disable LLDP on the LAN interface of a device, do the following:

     1. Open the web-based management interface and choose Administration >
        Discovery LLDP > Properties .
     2. Uncheck the LLDP Status check box.

    While this mitigation has been deployed and was proven successful in a test
    environment, customers should determine the applicability and effectiveness
    in their own environment and under their own use conditions. Customers
    should be aware that any workaround or mitigation that is implemented may
    negatively impact the functionality or performance of their network based
    on intrinsic customer deployment scenarios and limitations. Customers
    should not deploy any workarounds or mitigations before first evaluating
    the applicability to their own environment and any impact to such
    environment.

Fixed Software

  o Cisco has released free software updates that address the vulnerabilities
    described in this advisory. Customers may only install and expect support
    for software versions and feature sets for which they have purchased a
    license. By installing, downloading, accessing, or otherwise using such
    software upgrades, customers agree to follow the terms of the Cisco
    software license:
    https://www.cisco.com/c/en/us/products/end-user-license-agreement.html

    Additionally, customers may only download software for which they have a
    valid license, procured from Cisco directly, or through a Cisco authorized
    reseller or partner. In most cases this will be a maintenance upgrade to
    software that was previously purchased. Free security software updates do
    not entitle customers to a new software license, additional software
    feature sets, or major revision upgrades.

    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.

    Customers Without Service Contracts

    Customers who purchase directly from Cisco but do not hold a Cisco service
    contract and customers who make purchases through third-party vendors but
    are unsuccessful in obtaining fixed software through their point of sale
    should obtain upgrades by contacting the Cisco TAC: https://www.cisco.com/c
    /en/us/support/web/tsd-cisco-worldwide-contacts.html

    Customers should have the product serial number available and be prepared
    to provide the URL of this advisory as evidence of entitlement to a free
    upgrade.

    Fixed Releases

    In the following table(s), the left column lists Cisco firmware releases.
    The right column indicates whether a release is affected by the
    vulnerabilities described in this advisory and the first release that
    includes the fix for these vulnerabilities. Customers are advised to
    upgrade to an appropriate fixed firmware release as indicated in this
    section.

    Cisco Firmware Release                First Fixed Release
    1.2.0.6 and earlier                   1.2.1.2

    To download the firmware from the Software Center on Cisco.com, click
    Browse all and navigate to Switches > LAN Switches - Small Business > 220
    Series Smart Switches .

    The Cisco Product Security Incident Response Team (PSIRT) validates only
    the affected and fixed release information that is documented in this
    advisory.

Exploitation and Public Announcements

  o The Cisco PSIRT is not aware of any public announcements or malicious use
    of the vulnerabilities that are described in this advisory.

Source

  o Cisco would like to thank Qian Chen of the Codesafe Team of Legendsec at
    Qi'anxin Group for reporting these vulnerabilities.

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.

URL

  o https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-sb220-lldp-multivuls-mVRUtQ8T

Revision History

  o +----------+---------------------------+----------+--------+--------------+
    | Version  |        Description        | Section  | Status |     Date     |
    +----------+---------------------------+----------+--------+--------------+
    | 1.0      | Initial public release.   | -        | Final  | 2021-OCT-06  |
    +----------+---------------------------+----------+--------+--------------+

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