CVE-2023-31127 DMTF-2023-0001: SPDM mutual authentication bypass

Critical 9.1 Published 8 May 2023 Updated 28 Jan 2025

Attackers can bypass mutual authentication in SPDM session establishment by mixing DHE and PSK methods, affecting libspdm responders with specific capabilities.

Exploited in the wild: Not known
Login needed: Any signed-in user
Attackable: Local or same network only
Victim action needed: Not needed
Fix: None listed

What is CVE-2023-31127?

CVE-2023-31127 is a critical authentication bypass vulnerability in DMTF libspdm, published on 8 May 2023. It can only be exploited from the same machine or local network, with no action from the victim.

Official description

libspdm is a sample implementation that follows the DMTF SPDM specifications. A vulnerability has been identified in SPDM session establishment in libspdm prior to version 2.3.1. If a device supports both DHE session and PSK session with mutual authentication, the attacker may be able to establish the session with `KEY_EXCHANGE` and `PSK_FINISH` to bypass the mutual authentication. This is most likely to happen when the Requester begins a session using one method (DHE, for example) and then uses the other method's finish (PSK_FINISH in this example) to establish the session. The session hashes would be expected to fail in this case, but the condition was not detected.

This issue only impacts the SPDM responder, which supports `KEY_EX_CAP=1 and `PSK_CAP=10b` at same time with mutual authentication requirement. The SPDM requester is not impacted. The SPDM responder is not impacted if `KEY_EX_CAP=0` or `PSK_CAP=0` or `PSK_CAP=01b`. The SPDM responder is not impacted if mutual authentication is not required.

libspdm 1.0, 2.0, 2.1, 2.2, 2.3 are all impacted. Older branches are not maintained, but users of the 2.3 branch may receive a patch in version 2.3.2. The SPDM specification (DSP0274) does not contain this vulnerability.

Weakness: CWE-372, CWE-287

Which versions are affected by CVE-2023-31127?

It affects 1 product.

Products include Dmtf Libspdm.

How do I fix CVE-2023-31127?

No fix has been published for CVE-2023-31127 yet. Limit exposure of the affected software until one is available.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2023-31127 being exploited?

There is no known exploitation of CVE-2023-31127 in the wild and no public exploit code.

CVE-2023-32690 Responder can Invoke Undefined Behavior in libspdm Requester Medium 5.7

Sources

Also known as GHSA-qw76-4v8p-xq9f.