Product Affected

This issue can affect any router running Junos OS 10.2 or later, configured for BGP without the 'independent-domain' AS routing option enabled.
High
7.1 (AV:N/AC:M/Au:N/C:N/I:N/A:C)

Problem


A mutated BGP UPDATE message can cause the rpd daemon to crash. The crash is triggered by an UPDATE containing a corrupted ATTR_SET optional, transitive path attribute. Insufficient BGP path attribute exception handling resulted in an rpd crash.

This issue only affects routers configured for BGP running Junos 10.2 or later that do not have the 'independent-domain' routing option enabled. No earlier versions of Junos OS are affected by this issue.

Juniper SIRT is not aware of any malicious exploitation of this vulnerability

No other products or platforms are affected by this vulnerability.

Solution


The issue has been resolved in the releases listed below. ATTR_SET path attribute corruption no longer causes rpd to crash.

All Junos OS software releases built on or after 2011-11-03 have fixed this specific issue. Releases containing the fix specifically include: 10.4R8, 11.1R6, 11.2R4, 11.3R3, 11.4R1 and all subsequent releases (i.e. all releases built after 11.4R1).

This issue is being tracked as PR 691196 and is visible on the Customer Support website.

KB16765 [juniper.net] - "In which releases are vulnerabilities fixed?" describes which release vulnerabilities are fixed as per our End of Engineering and End of Life support policies.


How to obtain fixed software:

Security vulnerabilities in Junos are fixed in the next available Maintenance Release of each supported Junos version. In some cases, a Maintenance Release is not planned to be available in an appropriate time-frame. For these cases, Service Releases are made available in order to be more timely. Security Advisory and Security Notices will indicate which Maintenance and Service Releases contain fixes for the issues described. Upon request to JTAC, customers will be provided download instructions for a Service Release. Although Juniper does not provide formal Release Note documentation for a Service Release, a list of "PRs fixed" can be provided on request.

Workaround


Starting with Junos 10.2, an additional configuration option, called 'drop-path-attributes', was added to allow the router to completely drop specific path attributes. This configuration option allows customers to filter invalid or undesired path attributes, and completely mitigates this issue. To protect routers from corrupt ATTR_SET path attributes, configure the option as follows: 
[edit protocols bgp]
user@junos# set drop-path-attributes 128

See PSN-2011-09-380 for more information about using 'drop-path-attributes' as an effective mitigation technique.

Acknowledgement
Juniper SIRT would like to acknowledge and thank Sven Weizenegger and Nick Schneider of T-Systems for responsibly reporting this vulnerability.

Severity Assessment

Information for how Juniper Networks uses CVSS can be found at KB 16446 [juniper.net] "Common Vulnerability Scoring System (CVSS) and Juniper's Security Advisories."

Related Information