A Use of Incorrect Operator vulnerability in the Routing Engine firewall of Juniper Networks Junos OS Evolved allows an unauthenticated, network-based attacker to bypass security restrictions.

When a firewall filter which is applied to the lo0 or re:mgmt interface references a prefix list with 'from prefix-list', and that prefix list contains more than 10 entries, the prefix list doesn't match and packets destined to or from the local device are not filtered.
This issue affects firewall filters applied to the re:mgmt interfaces as input and output, but only affects firewall filters applied to the lo0 interface as output.
This issue is applicable to IPv4 and IPv6 as a prefix list can contain IPv4 and IPv6 prefixes.

 

This issue affects Junos OS Evolved:

• 23.2R2-S3-EVO versions before 23.2R2-S4-EVO,
• 23.4R2-S3-EVO versions before 23.4R2-S5-EVO,
• 24.2R2-EVO versions before 24.2R2-S1-EVO,
• 24.4-EVO versions before 24.4R1-S3-EVO, 24.4R2-EVO.

This issue doesn't affect Junos OS Evolved versions before 23.2R1-EVO.

 

A system will only be affected by this vulnerability if like in the following example a firewall filter applied to the lo0 or re:mgmt interface references a prefix list with the 'from prefix-list' clause, and that prefix list contains more than 10 entries:

[ policy-options prefix-list <prefix-list name> <prefix1> ]
...
[ policy-options prefix-list <prefix-list name> <prefix11> ]
...
[ firewall family <inet/inet6> filter <filter name> term <term name> from prefix-list <prefix-list name> ]
[ interfaces <lo0 unit <unit> / re:mgmt<0/1> unit <unit>> family <inet/inet6> filter <input/output> <filter name> ]