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             AUSCERT External Security Bulletin Redistribution

          Cisco IOS XR Software Border Gateway Protocol Denial of
                           Service Vulnerability
                              23 January 2020


        AusCERT Security Bulletin Summary

Product:           Cisco IOS XR Software
Publisher:         Cisco Systems
Operating System:  Network Appliance
Impact/Access:     Denial of Service -- Existing Account
Resolution:        Patch/Upgrade
CVE Names:         CVE-2019-1909  

Original Bulletin: 

Revision History:  January 23 2020: Republished.
                   July     4 2019: Initial Release

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

Cisco IOS XR Software Border Gateway Protocol Denial of Service Vulnerability

Priority:        Medium

Advisory ID:     cisco-sa-20190703-iosxr-bgp-dos

First Published: 2019 July 3 16:00 GMT

Last Updated:    2020 January 22 16:01 GMT

Version 1.1:     Final

Workarounds:     No workarounds availableCisco Bug IDs:   CSCvo90073



CVSS Score:


  o A vulnerability in the implementation of Border Gateway Protocol (BGP)
    functionality in Cisco IOS XR Software could allow an unauthenticated,
    remote attacker to cause a denial of service (DoS) condition on an affected

    The vulnerability is due to incorrect processing of certain BGP update
    messages. An attacker could exploit this vulnerability by sending BGP
    update messages that include a specific set of attributes to be processed
    by an affected system. A successful exploit could allow the attacker to
    cause the BGP process to restart unexpectedly, resulting in a DoS

    The Cisco implementation of BGP accepts incoming BGP traffic from
    explicitly defined peers only. To exploit this vulnerability, the malicious
    BGP update message would need to come from a configured, valid BGP peer or
    would need to be injected by the attacker into the victim's BGP network on
    an existing, valid TCP connection to a BGP peer.

    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 IOS XR
    Software Releases prior to 6.6.2 and 7.0.1.

    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.


  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 and Alerts 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

    Fixed Releases

    At the time of publication, Cisco IOS XR Software releases 6.6.2 and later
    and 7.0.1 and later contained the fix for this vulnerability. Available
    SMUs were as follows:

       6.4.2: ASR9K: AA15449
       6.5.3: ASR9K: AA15448

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       |
    | 1.1     | Republished.             | -       | Final  | 2020-January-22 |
    | 1.0     | Initial public release.  | -       | Final  | 2019-July-03    |

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

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