CSPACE-ATT-02: Attestation token is cryptographically verified (signature/issuer/audience/freshness)¶
| Property | Value |
|---|---|
| Severity | high |
| Platform | GCP Confidential Space (AMD SEV-SNP) |
| Lifecycle stage | attest |
| Policy | P-04: Attestation evidence is fresh and fully verified |
| Mode | Passive: reads only the files and values you pass to the scan. |
How to fix¶
- Before trusting any claim, verify the token's RS256 signature against the Confidential Space JWKS, and enforce iss=confidentialcomputing.googleapis.com, the expected audience (pass --expected-audience), and exp/nbf freshness. A present oemid must equal Google's PEN 11129. Claims-only inspection accepts forged and expired tokens.
- Verify the token's RS256 signature against the Confidential Space JWKS and enforce iss/aud/exp/nbf and oemid=11129 before trusting any claim.
After the fix, scan again: the check should report PASS.
When it is not assessed¶
SKIP:
- No --attestation-token provided; skipping token verification.
ERROR:
- Could not read token or fetch the Confidential Space JWKS: …
Scan inputs¶
The untrust scan options this check reads:
| Option | Description |
|---|---|
--attestation-token |
Path to a captured Confidential Space attestation token (JWT). |
--expected-audience |
Expected attestation-token audience (STS audience). |
Permissions¶
None. The check reads only the files or values you pass to the scan.
Related¶
- Other checks for policy P-04: CCA-CERT-01, CSPACE-ATT-01, CSPACE-ATT-03, GPU-CERT-01, GPUCC-ATT-01, NITRO-ATT-02, NITRO-ATT-03, SE-CERT-01, SGX-CERT-01, SNP-CERT-01, TDX-CERT-01
Generated from untrust 1.3.0 (commit 7ef462d9a0c3).