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AUSCERT External Security Bulletin Redistribution
Cisco IOS XR Software Border Gateway Protocol Denial of
4 July 2019
AusCERT Security Bulletin Summary
Product: Cisco IOS XR Software
Publisher: Cisco Systems
Operating System: Network Appliance
Impact/Access: Denial of Service -- Existing Account
CVE Names: CVE-2019-1909
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TITLE: Cisco IOS XR Software Border Gateway Protocol Denial of Service Vulnerability
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Cisco IOS XR Software Border Gateway Protocol Denial of Service Vulnerability
Advisory ID: cisco-sa-20190703-iosxr-bgp-dos
First Published: 2019 July 3 16:00 GMT
Version 1.0: Final
Workarounds: No workarounds availableCisco Bug IDs: CSCvo90073
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:
o The information provided in this advisory is the best available information
as of the time of publication. Please consult the Release Note Enclosure on
any associated bug ID for the most complete, accurate, and up-to-date
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 additional information is needed, customers are advised to contact the
Cisco Technical Assistance Center (TAC) or their contracted maintenance
At the time of publication, this vulnerability affected Cisco IOS XR
Software Releases prior to 6.6.2 and 7.0.1.
Products Confirmed Not Vulnerable
Only products listed in the Vulnerable Products section of this advisory
are known to be affected by this vulnerability.
At the time of publication, Releases 6.6.2 and later and 7.0.1 and later
contained the fix for this vulnerability. Available SMUs were the
6.4.2: ASR9K: AA15449
6.5.3: ASR9K: AA15448
o There are no workarounds that address this vulnerability.
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.
| Version | Description | Section | Status | Date |
| 1.0 | Initial public release. | - | Final | 2019-July-03 |
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