GHSA-72c7-4g63-hpw5
go-witness is Vulnerable to Improper Verification of AWS EC2 Identity Documents
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
Blast Radius
github.com/in-toto/go-witnessReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
This vulnerability only affects users of the AWS attestor.
Users of the AWS attestor could have unknowingly received a forged identity document. While this may seem unlikely, AWS recently issued a security bulletin about IMDS (Instance Metadata Service) impersonation.1
There are multiple locations where the verification of the identity document will mistakenly report a successful verification.
-
If a signature is not present or is empty https://github.com/in-toto/go-witness/blob/0c8bb30c143951d88b1d4b32f260c5f67d30137b/attestation/aws-iid/aws-iid.go#L161-L163
-
If the RSA verification of the document fails for any reason https://github.com/in-toto/go-witness/blob/0c8bb30c143951d88b1d4b32f260c5f67d30137b/attestation/aws-iid/aws-iid.go#L192-L196
Workarounds
The contents of the AWS attestation contain the identity document, signature, and public key that was used to verify the document. These attestations and their could be identity documents could be manually verified with the openssl command line as documented in the below reference from AWS.2
However, the certificate containing the public key was hard-coded into the attestor. https://github.com/in-toto/go-witness/blob/0c8bb30c143951d88b1d4b32f260c5f67d30137b/attestation/aws-iid/aws-iid.go#L46-L66
Since the original authoring of the attestor, AWS has moved to region specific public certificates. The currently valid certificates were issued around April of 2024, making the identification of attestations with forged content difficult without additional trusted data proving the AWS region in which the attestation was created.
Patches
This vulnerability is addressed in go-witness 0.9.1 and witness 0.10.1.
Resources
Footnotes
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/in-toto/go-witness | all versions | 0.9.1 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/in-toto/go-witness. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update github.com/in-toto/go-witness to 0.9.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-72c7-4g63-hpw5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-72c7-4g63-hpw5 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-72c7-4g63-hpw5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-72c7-4g63-hpw5 in your dependencies?
O3 detects GHSA-72c7-4g63-hpw5 across Go dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.