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AUSCERT External Security Bulletin Redistribution
ESB-2019.2441.2
Cisco IOS XR Software Border Gateway Protocol Denial of
Service Vulnerability
23 January 2020
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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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190703-iosxr-bgp-dos
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
CVE-2019-1909
CWE-20
CVSS Score:
6.8 AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H/E:X/RL:X/RC:X
Summary
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
system.
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
condition.
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:
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/
cisco-sa-20190703-iosxr-bgp-dos
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.
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 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
providers.
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.
Source
o This vulnerability was found during the resolution of a Cisco TAC support
case.
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-20190703-iosxr-bgp-dos
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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