A vulnerability in the processing of traffic matching a firewall filter containing a syslog action in Juniper Networks Junos OS on MX Series with MPC10/MPC11 cards installed, PTX10003 and PTX10008 Series devices, will cause the line card to crash and restart, creating a Denial of Service (DoS). Continued receipt and processing of packets matching the firewall filter can create a sustained Denial of Service (DoS) condition. When traffic hits the firewall filter, configured on lo0 or any physical interface on the line card, containing a term with a syslog action (e.g. 'term <name> then syslog'), the affected line card will crash and restart, impacting traffic processing through the ports of the line card. This issue only affects MX Series routers with MPC10 or MPC11 line cards, and PTX10003
The following software releases have been updated to resolve this specific issue: Junos OS 19.4R3-S2, 20.1R3, 20.2R2-S2, 20.2R3, 20.3R3, 20.4R2, 21.1R1, and all subsequent releases. Junos OS Evolved 20.4R2-EVO, 21.1R1-EVO, and all subsequent releases.
Remove the "syslog" action from the firewall filter configuration.
| Product | Vulnerable range | Fixed version | Advisory |
|---|---|---|---|
| Juniper Networks Junos OS | >=19.3<19.3R3-S2 | 19.3R3-S2 | advisory ↗ |
| Juniper Networks Junos OS | >=19.4<19.4R3-S2 | 19.4R3-S2 | advisory ↗ |
| Juniper Networks Junos OS | >=20.1<20.1R3 | 20.1R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.2<20.2R2-S2, 20.2R3 | 20.2R2-S2, 20.2R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.3<20.3R3 | 20.3R3 | advisory ↗ |
| Juniper Networks Junos OS | >=20.4<20.4R2 | 20.4R2 | advisory ↗ |
| Juniper Networks Junos OS Evolved | >=unspecified<20.4R2-EVO | 20.4R2-EVO | advisory ↗ |