Juniper Networks Junos OS SIP ALG Denial-of-Service Vulnerability on MX Series with MS-MPC

A denial-of-service vulnerability has been identified in the SIP Application Layer Gateway (ALG) of Juniper Networks Junos OS, specifically on MX Series devices with MS-MPC. This vulnerability allows an unauthenticated, network-based attacker to cause a crash and restart of the MS-MPC. The issue arises when the device is configured with two or more service sets processing SIP calls. A specific sequence of call events can trigger the crash. The vulnerability affects all Junos OS versions prior to 21.2R3-S9, 21.4 from 21.4R1, 22.2 prior to 22.2R3-S6, and 22.4 prior to 22.4R3-S6. Devices with MX-SPC3 or those running Junos OS versions after 22.4 are not affected.

Impact

Exploitation of this vulnerability leads to a crash and restart of the affected MS-MPC, causing a temporary denial-of-service condition on the device.