CVE-2022-39249
Vulnérabilité élevée dans matrix-js-sdk (matrix-org)
Description
Matrix Javascript SDK is the Matrix Client-Server SDK for JavaScript. Prior to version 19.7.0, an attacker cooperating with a malicious homeserver can construct messages appearing to have come from another person. Such messages will be marked with a grey shield on some platforms, but this may be missing in others. This attack is possible due to the matrix-js-sdk implementing a too permissive key forwarding strategy on the receiving end. Starting with version 19.7.0, the default policy for accepting key forwards has been made more strict in the matrix-js-sdk. matrix-js-sdk will now only accept forwarded keys in response to previously issued requests and only from own, verified devices. The SDK now sets a `trusted` flag on the decrypted message upon decryption, based on whether the key used to decrypt the message was received from a trusted source. Clients need to ensure that messages decrypted with a key with `trusted = false` are decorated appropriately, for example, by showing a warning for such messages. This attack requires coordination between a malicious homeserver and an attacker, and those who trust your homeservers do not need a workaround.
Gravité et risque d'exploitation
CVE-2022-39249 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 1.28 %, ce qui la place devant 69.5 % des CVE référencées.
Que faire ?
- Vérifiez si matrix-js-sdk (versions < 19.7.0) 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.
Références
- https://github.com/matrix-org/matrix-js-sdk/commit/a587d7c36026fe1fcf93dfff63588abee359be76
- https://github.com/matrix-org/matrix-js-sdk/releases/tag/v19.7.0
- https://github.com/matrix-org/matrix-js-sdk/security/advisories/GHSA-6263-x97c-c4gg
- https://github.com/matrix-org/matrix-spec-proposals/pull/3061
- https://matrix.org/blog/2022/09/28/upgrade-now-to-address-encryption-vulns-in-matrix-sdks-and-clients
- https://security.gentoo.org/glsa/202210-35