Product Affected

This issue can affect any Junos device configured with multicast tunnel interfaces.
Medium
6.1 (AV:A/AC:L/Au:N/C:N/I:N/A:C)

Problem


Crafted GRE packets received on a multicast tunnel (mt- or gr-) interface that are allowed to reach the Routing Engine (RE) may cause the Junos kernel to crash.

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

No other Juniper Networks products or platforms are affected by this issue.

Solution


All Junos OS software releases built on or after 2013-01-25 have fixed this specific issue. Releases containing the fix specifically include: 10.4R12, 11.4R6, 11.4X27.44 (MX BBE), 12.1R5, 12.1X44-D15 (SRX), 12.2R2, 12.3X50-D11 (ACX), 12.3X50-D20 (QFX), 12.3R1, and all subsequent releases (i.e. all releases built after 12.3R1).

Customers can confirm the build date of any Junos OS release by issuing the command ' show version detail '.

This issue is being tracked as PR 821503 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


Use access lists or firewall filters on all loopback interfaces (including routing-instances) to limit access of packets with protocol GRE is received on mt- or gr- interfaces. For example:

[ edit firewall family inet filter <loopback> term <x> ]
  from
    protocol gre
  then
    discard

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