Product Affected

This issue can affect any Junos router with the PIM multicast protocol enabled.
Medium
5.4 (AV:N/AC:H/Au:N/C:N/I:N/A:C)

Problem


During internal stress and conformance testing of the PIM multicast protocol, the rpd routing daemon on the router crashed. The crash was triggered by a specifically crafted bootstrap message (BSM) received by the PIM router. Due to the inconsistent values found in the messages, rpd executed an unhandled exception and crashed. This issue can affect both IPv4 PIM and IPv6 PIM (PIMv6).

This issue has not been found to be exploited in the wild. While the effect of this software defect is serious, exploit of the vulnerability has proven to be exceedingly difficult to replicate, even with crafted, stateful packet playback.

Solution


The inconsistency of field values is now handled and a syslog message is generated.

All Junos software releases built on or after 2011-06-24 have fixed this specific issue. Releases containing the fix specifically include: 9.3S20, 10.0S17, 10.4R3, 11.1R1, and all subsequent releases (i.e. all releases built after 11.1R1).

This issue is being tracked as PR 556375. While this PR may not be viewable by customers, it can be used as a reference when discussing the issue with JTAC.

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


  1. Create a bootstrap-import policy under [protocols pim] that will block malicious packets before BSR packet processing, thereby preventing the crash: 
    user@Junos> show configuration protocols pim

rp {
    bootstrap-import no-bsr;
    }
}
    Add all interfaces to the policy that should never receive PIM BSR packets: 
    user@Junos> show configuration policy-options policy-statement no-bsr
 
from interface xe-0/0/0.0;
then reject;

  2. For networks running both IPv4 and IPv6 PIM, an alternate set of configuration options may be used: 
    user@Junos# set protocols pim rp bootstrap family inet import no-bsr
user@Junos# set protocols pim rp bootstrap family inet6 import no-bsr
    As with the previous example, add all interfaces to the policy that should never receive PIM or PIMv6 BSR packets: 
    user@Junos> show configuration policy-options policy-statement no-bsr

from interface xe-0/0/0.0;
then reject;

  3. Utilize a firewall filter to only accept PIM packets from trusted sources.

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."

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