An Improper Validation of Syntactic Correctness of Input vulnerability in Packet Forwarding Engine (PFE) of Juniper Networks Junos OS allows an unauthenticated, network-based attacker to cause Denial of Service (DoS). On all Junos OS MX Series and SRX Series platforms, when SIP ALG is enabled, and a specific SIP packet is received and processed, NAT IP allocation fails for genuine traffic, which causes Denial of Service (DoS). Continuous receipt of this specific SIP ALG packet will cause a sustained DoS condition. NAT IP usage can be monitored by running the following command. user@srx> show security nat resource-usage source-pool <source_pool_name> Pool name: source_pool_name .. Address Factor-index Port-range Used Avail Total Usage X.X.X.X 0 Single Ports 50258 52342 62464 96% <<<<<
The following software releases have been updated to resolve this specific issue: Junos OS 21.2R3-S6, 21.3R3-S5, 21.4R3-S5, 22.1R3-S4, 22.2R3-S3, 22.3R3-S1, 22.4R2-S2, 22.4R3, 23.2R1-S1, 23.2R2, 23.4R1, and all subsequent releases.
There are no known workarounds for this issue, but it should be considered to disable the SIP ALG if it's not strictly needed.
| Product | Vulnerable range | Fixed version | Advisory |
|---|---|---|---|
| Juniper Networks Junos OS | <21.2R3-S6 | 21.2R3-S6 | advisory ↗ |
| Juniper Networks Junos OS | >=21.3<21.3R3-S5 | 21.3R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=21.4<21.4R3-S5 | 21.4R3-S5 | advisory ↗ |
| Juniper Networks Junos OS | >=22.1<22.1R3-S4 | 22.1R3-S4 | advisory ↗ |
| Juniper Networks Junos OS | >=22.2<22.2R3-S3 | 22.2R3-S3 | advisory ↗ |
| Juniper Networks Junos OS | >=22.3<22.3R3-S1 | 22.3R3-S1 | advisory ↗ |
| Juniper Networks Junos OS | >=22.4<22.4R2-S2, 22.4R3 | 22.4R2-S2, 22.4R3 | advisory ↗ |
| Juniper Networks Junos OS | >=23.2<23.2R1-S1, 23.2R2 | 23.2R1-S1, 23.2R2 | advisory ↗ |