CVE Database

kas is a setup tool for bitbake based projects. Starting in version 4.8 and prior to version 5.3, kas checks out and processes repositories regarding configuration includes prior to validating signatures of those repositories. This may allow to replace on original repository with one under the control of an attacker under very specific conditions. First of all, the attacker must have gained control of a repository that a kas file of the victim is referencing. Furthermore, the following conditions must be fulfilled: the victim's kas configuration must include a configuration file from the attacked repository; the repository state is referenced by tag, and no commit ID is specified (this is triggering a warning, though); the key used for validating the tag or commit signature is stored as file in a repository; no fingerprint for the key is specified; and the `_source_dir` key must not be set by the victim when calling kas (e.g. by avoiding a local `.config.yaml`). Given these conditions, the attacker could modify the included kas configuration in way that the key used to validate the tag signature of the attacker's repository could be replaced by an attacker-chosen key. No other exploit possibilities have been identified so far, but this does not rule out that those may exist. All patches have been released along with kas version 5.3. As a workaround, pin the expected signature key via its fingerprint, also when storing it as file in a repository.

kas is a setup tool for bitbake based projects. Prior to version 5.3, when relying solely on a git commit ID (SHA-1 or SHA-256) to qualify if a checkout of a repository is equivalent to the state validated while adding its commit ID to a kas configuration, users may be tricked to check out a branch of the same name from this repository. This implies that the referenced repository has been taken over by an attacker and modified to carry such a branch. SHA-1 commits may also be replaced by creating hash collisions, so the primary impact of this issue is on SHA-256 commit IDs. Version 5.3 fixes the issue. As a workaround, avoid relying solely on the commit ID for integrity validation of a repository that might become under control of a malicious 3rd party. If available, additional validate cryptographically signed commits or tags. Alternatively, mirror the repository to a save place, validate its integrity, and use this instead of the original one.

sigstore-java is a sigstore java client for interacting with sigstore infrastructure. Version 2.0.0 erroneously removed verification of the integrated (Rekor entry) time) against the Fulcio certificate. Version 2.1.0 re-added this verification with enhancements that adhere to the Sigstore verification spec. The old sigstore-conformance test for this check was built incorrectly. This vulnerability impacts only users verifying bundles with `dev.sigstore:sigstore-java:2.0.0`. Older versions are not affected; it is fixed in `dev.sigstore:sigstore-java:2.1.0` A malicious actor may exploit this if they were able to access a users system and exfiltrate the temporary private key used during signing and then reuse an old fulcio certificate later without requiring direct access to the user's credentials. Users may protect themselves by re-verifying their artifacts using the newest sigstore-java or another current sigstore client. Transparency logs may also be audited for unauthorized signatures for a suspected reused identity.