An Improper Validation of Syntactic Correctness of Input vulnerability in the SIP plugin of Juniper Networks Junos OS on MX Series with SPC3 and SRX Series allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).If the SIP ALG is enabled on an affected device, the processing of a malformed SIP invite packet will cause a flow processing daemon (flowd) crash and restart. This leads to a complete service outage until the system has automatically recovered.
This issue affects Junos OS on MX Series with SPC3 and SRX Series:
- all versions before 23.2R2-S7,
- 23.4 versions before 23.4R2-S8,
- 24.2 versions before 24.2R2-S5,
- 24.4 versions before 24.4R2-S4,
- 25.2 versions before 25.2R2,
- 25.4 versions before 25.4R1-S2.
To be affected the SIP ALG needs to be enabled, either implicitly / by default or by way of configuration. Please verify with:
user@host> show security alg status | match sip
SIP : Enabled
Juniper SIRT is not aware of any malicious exploitation of this vulnerability.
There are no known workarounds for this issue.
To reduce the risk of exploitation customers not requiring the SIP ALG functionality could explicitly disable it (in case it's by default enabled) by configuring:
[ security alg sip disable ]
The following software releases have been updated to resolve this specific issue:
Junos OS: 23.2R2-S7, 23.4R2-S8, 24.2R2-S5, 24.4R2-S4, 25.2R2, 25.4R1-S2, 25.4R2, 26.2R1, and all subsequent releases.