CVE-2024-55655
Vulnérabilité faible dans sigstore-python (sigstore)
Description
sigstore-python is a Python tool for generating and verifying Sigstore signatures. Versions of sigstore-python newer than 2.0.0 but prior to 3.6.0 perform insufficient validation of the "integration time" present in "v2" and "v3" bundles during the verification flow: the "integration time" is verified *if* a source of signed time (such as an inclusion promise) is present, but is otherwise trusted if no source of signed time is present. This does not affect "v1" bundles, as the "v1" bundle format always requires an inclusion promise. Sigstore uses signed time to support verification of signatures made against short-lived signing keys. The impact and severity of this weakness is *low*, as Sigstore contains multiple other enforcing components that prevent an attacker who modifies the integration timestamp within a bundle from impersonating a valid signature. In particular, an attacker who modifies the integration timestamp can induce a Denial of Service, but in no different manner than already possible with bundle access (e.g. modifying the signature itself such that it fails to verify). Separately, an attacker could upload a *new* entry to the transparency service, and substitute their new entry's time. However, this would still be rejected at validation time, as the new entry's (valid) signed time would be outside the validity window of the original signing certificate and would nonetheless render the attacker auditable.
Gravité et risque d'exploitation
CVE-2024-55655 obtient un score CVSS de 2.7/10, soit une gravité faible. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.25 %, ce qui la place devant 15.6 % des CVE référencées.
Que faire ?
- Vérifiez si sigstore-python (versions >= 2.0.0, < 3.6.0) est présent sur votre parc.
- Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
- À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
- Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.