An Improper Handling of Additional Special Element vulnerability in the Packet Forwarding Engine (PFE) of Juniper Networks Junos OS on MX Series with MS-MPC, MS-MIC and SPC3, and SRX Series, allows an unauthenticated, network-based attacker to cause a Denial-of-Service (DoS).
If the SIP ALG processes specifically formatted SIP invites, a memory corruption will occur which will lead to a crash of the FPC processing these packets. Although the system will automatically recover with the restart of the FPC, subsequent SIP invites will cause the crash again and lead to a sustained DoS.
This issue affects Junos OS on MX Series and SRX Series:
- all versions before 21.2R3-S9,
- 21.4 versions before 21.4R3-S10,
- 22.2 versions before 22.2R3-S6,
- 22.4 versions before 22.4R3-S5,
- 23.2 versions before 23.2R2-S3,
- 23.4 versions before 23.4R2-S3,
- 24.2 versions before 24.2R1-S2, 24.2R2.
Weakness
The product receives input from an upstream component, but it does not handle or incorrectly handles when an additional unexpected special element is provided.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Junos | Juniper | * | 21.2 (excluding) |
| Junos | Juniper | 21.2 (including) | 21.2 (including) |
| Junos | Juniper | 21.2-r1 (including) | 21.2-r1 (including) |
| Junos | Juniper | 21.2-r1-s1 (including) | 21.2-r1-s1 (including) |
| Junos | Juniper | 21.2-r1-s2 (including) | 21.2-r1-s2 (including) |
| Junos | Juniper | 21.2-r2 (including) | 21.2-r2 (including) |
| Junos | Juniper | 21.2-r2-s1 (including) | 21.2-r2-s1 (including) |
| Junos | Juniper | 21.2-r2-s2 (including) | 21.2-r2-s2 (including) |
| Junos | Juniper | 21.2-r3 (including) | 21.2-r3 (including) |
| Junos | Juniper | 21.2-r3-s1 (including) | 21.2-r3-s1 (including) |
| Junos | Juniper | 21.2-r3-s2 (including) | 21.2-r3-s2 (including) |
| Junos | Juniper | 21.2-r3-s3 (including) | 21.2-r3-s3 (including) |
| Junos | Juniper | 21.2-r3-s4 (including) | 21.2-r3-s4 (including) |
| Junos | Juniper | 21.2-r3-s5 (including) | 21.2-r3-s5 (including) |
| Junos | Juniper | 21.2-r3-s6 (including) | 21.2-r3-s6 (including) |
| Junos | Juniper | 21.2-r3-s7 (including) | 21.2-r3-s7 (including) |
| Junos | Juniper | 21.2-r3-s8 (including) | 21.2-r3-s8 (including) |
| Junos | Juniper | 21.4 (including) | 21.4 (including) |
| Junos | Juniper | 21.4-r1 (including) | 21.4-r1 (including) |
| Junos | Juniper | 21.4-r1-s1 (including) | 21.4-r1-s1 (including) |
| Junos | Juniper | 21.4-r1-s2 (including) | 21.4-r1-s2 (including) |
| Junos | Juniper | 21.4-r2 (including) | 21.4-r2 (including) |
| Junos | Juniper | 21.4-r2-s1 (including) | 21.4-r2-s1 (including) |
| Junos | Juniper | 21.4-r2-s2 (including) | 21.4-r2-s2 (including) |
| Junos | Juniper | 21.4-r3 (including) | 21.4-r3 (including) |
| Junos | Juniper | 21.4-r3-s1 (including) | 21.4-r3-s1 (including) |
| Junos | Juniper | 21.4-r3-s2 (including) | 21.4-r3-s2 (including) |
| Junos | Juniper | 21.4-r3-s3 (including) | 21.4-r3-s3 (including) |
| Junos | Juniper | 21.4-r3-s4 (including) | 21.4-r3-s4 (including) |
| Junos | Juniper | 21.4-r3-s5 (including) | 21.4-r3-s5 (including) |
| Junos | Juniper | 21.4-r3-s6 (including) | 21.4-r3-s6 (including) |
| Junos | Juniper | 21.4-r3-s7 (including) | 21.4-r3-s7 (including) |
| Junos | Juniper | 21.4-r3-s8 (including) | 21.4-r3-s8 (including) |
| Junos | Juniper | 21.4-r3-s9 (including) | 21.4-r3-s9 (including) |
| Junos | Juniper | 22.2 (including) | 22.2 (including) |
| Junos | Juniper | 22.2-r1 (including) | 22.2-r1 (including) |
| Junos | Juniper | 22.2-r1-s1 (including) | 22.2-r1-s1 (including) |
| Junos | Juniper | 22.2-r1-s2 (including) | 22.2-r1-s2 (including) |
| Junos | Juniper | 22.2-r2 (including) | 22.2-r2 (including) |
| Junos | Juniper | 22.2-r2-s1 (including) | 22.2-r2-s1 (including) |
| Junos | Juniper | 22.2-r2-s2 (including) | 22.2-r2-s2 (including) |
| Junos | Juniper | 22.2-r3 (including) | 22.2-r3 (including) |
| Junos | Juniper | 22.2-r3-s1 (including) | 22.2-r3-s1 (including) |
| Junos | Juniper | 22.2-r3-s2 (including) | 22.2-r3-s2 (including) |
| Junos | Juniper | 22.2-r3-s3 (including) | 22.2-r3-s3 (including) |
| Junos | Juniper | 22.2-r3-s4 (including) | 22.2-r3-s4 (including) |
| Junos | Juniper | 22.2-r3-s5 (including) | 22.2-r3-s5 (including) |
| Junos | Juniper | 22.4 (including) | 22.4 (including) |
| Junos | Juniper | 22.4-r1 (including) | 22.4-r1 (including) |
| Junos | Juniper | 22.4-r1-s1 (including) | 22.4-r1-s1 (including) |
| Junos | Juniper | 22.4-r1-s2 (including) | 22.4-r1-s2 (including) |
| Junos | Juniper | 22.4-r2 (including) | 22.4-r2 (including) |
| Junos | Juniper | 22.4-r2-s1 (including) | 22.4-r2-s1 (including) |
| Junos | Juniper | 22.4-r2-s2 (including) | 22.4-r2-s2 (including) |
| Junos | Juniper | 22.4-r3 (including) | 22.4-r3 (including) |
| Junos | Juniper | 22.4-r3-s1 (including) | 22.4-r3-s1 (including) |
| Junos | Juniper | 22.4-r3-s2 (including) | 22.4-r3-s2 (including) |
| Junos | Juniper | 22.4-r3-s3 (including) | 22.4-r3-s3 (including) |
| Junos | Juniper | 22.4-r3-s4 (including) | 22.4-r3-s4 (including) |
| Junos | Juniper | 23.2 (including) | 23.2 (including) |
| Junos | Juniper | 23.2-r1 (including) | 23.2-r1 (including) |
| Junos | Juniper | 23.2-r1-s1 (including) | 23.2-r1-s1 (including) |
| Junos | Juniper | 23.2-r1-s2 (including) | 23.2-r1-s2 (including) |
| Junos | Juniper | 23.2-r2 (including) | 23.2-r2 (including) |
| Junos | Juniper | 23.2-r2-s1 (including) | 23.2-r2-s1 (including) |
| Junos | Juniper | 23.2-r2-s2 (including) | 23.2-r2-s2 (including) |
| Junos | Juniper | 23.4 (including) | 23.4 (including) |
| Junos | Juniper | 23.4-r1 (including) | 23.4-r1 (including) |
| Junos | Juniper | 23.4-r1-s1 (including) | 23.4-r1-s1 (including) |
| Junos | Juniper | 23.4-r1-s2 (including) | 23.4-r1-s2 (including) |
| Junos | Juniper | 23.4-r2 (including) | 23.4-r2 (including) |
| Junos | Juniper | 23.4-r2-s1 (including) | 23.4-r2-s1 (including) |
| Junos | Juniper | 23.4-r2-s2 (including) | 23.4-r2-s2 (including) |
| Junos | Juniper | 24.2 (including) | 24.2 (including) |
| Junos | Juniper | 24.2-r1 (including) | 24.2-r1 (including) |
| Junos | Juniper | 24.2-r1-s1 (including) | 24.2-r1-s1 (including) |
| Junos | Juniper | 24.2-r2 (including) | 24.2-r2 (including) |
Potential Mitigations
- Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.