جزئیات آسیب‌پذیری

Kyverno is a policy engine for Kubernetes. In versions 1.14.0 through 1.19.0, the ImageValidatingPolicy (policies.kyverno.io/v1beta1) evaluator never reads the spec.images and spec.allowedValues fields of a PolicyException. Any PolicyException whose policyRefs and matchConditions match a resource causes image signature verification to be skipped for the entire resource rather than only for the listed images or values, so an exception intended to exempt a single trusted image exempts every image on the matched resource(s). As a result, unsigned or untrusted images can be admitted to the cluster without signature verification. This differs from ValidatingPolicy, GeneratingPolicy, and MutatingPolicy, which treat the same field as a partial exemption. The issue is fixed in version 1.19.1.

• https://www.vulncheck.com/advisories/kyverno-before-1.19.1-imagevalidatingpolicy-exception-bypass third-party-advisory
• https://github.com/kyverno/kyverno/security/advisories/GHSA-5cjf-wwfg-pj4c vendor-advisory