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             AUSCERT External Security Bulletin Redistribution

          Cisco Email Security Appliance Shortened URL Denial of
                           Service Vulnerability
                             21 February 2020


        AusCERT Security Bulletin Summary

Product:           Cisco Email Security Appliance
Publisher:         Cisco Systems
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Remote/Unauthenticated
Resolution:        Patch/Upgrade
CVE Names:         CVE-2020-3132  

Original Bulletin: 

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

Cisco Email Security Appliance Shortened URL Denial of Service Vulnerability

Priority:        Medium

Advisory ID:     cisco-sa-esa-shrt-dos-wM54R8qA

First Published: 2020 February 19 16:00 GMT

Version 1.0:     Final

Workarounds:     YesCisco Bug IDs:   CSCvp75565



CVSS Score:


  o A vulnerability in the email message scanning feature of Cisco AsyncOS
    Software for Cisco Email Security Appliance (ESA) could allow an
    unauthenticated, remote attacker to cause a temporary denial of service
    (DoS) condition on an affected device.

    The vulnerability is due to inadequate parsing mechanisms for specific
    email body components. An attacker could exploit this vulnerability by
    sending a malicious email containing a high number of shortened URLs
    through an affected device. A successful exploit could allow the attacker
    to consume processing resources, causing a DoS condition on an affected
    device. To successfully exploit this vulnerability, certain conditions
    beyond the control of the attacker must occur.

    Cisco has released software updates that address the vulnerability
    described in this advisory. There is a workaround that addresses this

    This advisory is available at the following link:

Affected Products

  o Vulnerable Products

    At the time of publication, this vulnerability affected Cisco ESA and Cisco
    Cloud Email Security (CES) s oftware releases earlier than 12.5.1-037 and
    earlier than 13.0.0-375.

    Products Confirmed Not Vulnerable

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


  o Administrators can disable email URL filtering for shortened URLs by
    connecting to a device through the CLI and typing the command
    websecurityadvancedconfig . Under Do you want to enable URL filtering for
    shortened URLs type N and commit the changes. URL filtering for shortened
    URLs is enabled by default.

Fixed Software

  o Cisco has released software updates that address the vulnerability
    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/

    Fixed Releases

    At the time of publication, Cisco ESA and Cisco CES software releases
    12.5.1-037 and later and 13.0.0-375 and later contained the fix for this

    Cisco Cloud Email Security (CES) includes the Cisco ESA and Cisco Content
    Security Management Appliance (SMA) as part of the service solution. Cisco
    provides regular maintenance of the products included in this solution.
    Customers can also request a software upgrade by contacting Cisco CES

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 during the resolution of a Cisco TAC support

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-FEB-19  |

- --------------------------END INCLUDED TEXT--------------------

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