Intel(R) TDX Workload Attestation software · Vulnerability

Improper certificate validation for some Intel(R) TDX Workload Attestation software within Ring 3: User Applications may allow an escalation of privilege. Unprivileged software adversary with an unauthenticated user combined with a low complexity attack may enable data manipulation. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (none), integrity (high) and availability (none) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

Improper certificate validation for some Intel(R) TDX Workload Attestation software within Ring 3: User Applications may allow an escalation of privilege. Unprivileged software adversary with an unauthenticated user combined with a low complexity attack may enable data manipulation. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (none), integrity (high) and availability (none) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

Improper certificate validation for some Intel(R) TDX Workload Attestation software within Ring 3: User Applications may allow an escalation of privilege. Unprivileged software adversary with an unauthenticated user combined with a low complexity attack may enable data manipulation. This result may potentially occur via local access when attack requirements are present without special internal knowledge and requires no user interaction. The potential vulnerability may impact the confidentiality (none), integrity (high) and availability (none) of the vulnerable system, resulting in subsequent system confidentiality (none), integrity (none) and availability (none) impacts.

`tdx_workload_attestation::verification::x509::verify_x509_cert()`, available with the `host-verification` feature, checked that `issuer_cert` issued `cert` and verified the certificate signature. It did not check the certificate's validity period, so it accepted expired and not-yet-valid certificates. With the `host-gcp-tdx` feature, this function validates the GCP launch endorsement signing certificate against the GCE confidential-computing TCB root certificate. A signing certificate outside its validity period was therefore still accepted during launch endorsement verification. Intel describes the issue as improper certificate validation and classifies it as escalation of privilege, with a CVSS 4.0 base score of 5.9, in INTEL-SA-01520. The flaw was corrected in [#86](https://github.com/IntelLabs/tdx-workload-attestation/pull/86), released in 0.2.0. The function now returns `Ok(false)` when the current time is outside the certificate's `notBefore`/`notAfter` range. Reported by [Borys Tsyrulnikov](https://borystsyrulnikov.dev).