Junos Firewall Bypass Vulnerability

Junos with the Trio-based PFE modules are affected from a security bybass vulnerability.

When configuring a stateless firewall filter on a system with Trio-based PFE modules (e.g. MX Series), any source or destination port matching condition may fail to match intended packets, causing the filter to not execute the actions specified in the 'then' clause. Depending on the intent and design of the interface filter, this match failure may have unexpected impact on the router or follow-on filter clauses. For example, if traffic with a specific destination port was designed to be accepted, a later 'reject all' clause may inadvertently discard wanted traffic. Conversely, if certain destination ports are meant to be dropped, malicious traffic may be consumed by the RE or forwarded on to downstream routers.

Junos OS 13.3 and 14.1

Checks if a vulnerable OS build is present on the target host.

Update to Junos OS OS 13.3R3-S3, 13.3R4, 14.1R3, 14.2R1, or any subsequent releases.