A denial-of-service vulnerability exists in the omec-project UPF (pfcpiface component) in version upf-epc-pfcpiface:2.1.3-dev. After PFCP association, a specially crafted PFCP Session Establishment Request with a CreatePDR that contains a malformed Flow-Description is not robustly validated. The Flow-Description parser (parseFlowDesc) can read beyond the bounds of the provided buffer, causing a panic and terminating the UPF process. An attacker who can send PFCP Session Establishment Request messages to the UPFs N4/PFCP endpoint can exploit this issue to repeatedly crash the UPF.
Weakness
The product reads data past the end, or before the beginning, of the intended buffer.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Upf | Opennetworking | 2.1.3-dev (including) | 2.1.3-dev (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.
- To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.