CVE-2015-8542
Publiée le 2016-12-15 · Dernière modification le 2026-06-17
Les versions d'Open-Xchange Guard antérieures à la 2.2.0-rev8 sont affectées par une faille d'authentification dans le processus de récupération des clés privées PGP. Un attaquant disposant d'un accès réseau de base, en tant qu'utilisateur ou invité, peut voler les clés privées d'autres utilisateurs en itérant à travers des identifiants séquentiels et en testant des mots de passe courants ou identiques. Comme cela ne nécessite aucun privilège particulier au-delà d'un compte de bas niveau et implique des paramètres prévisibles, l'exploitation est relativement simple à exécuter.
DÉTAIL DU VECTEUR CVSS
RÉFÉRENCES
Description officielle du NVD (en anglais)
An issue was discovered in Open-Xchange Guard before 2.2.0-rev8. The "getprivkeybyid" API call is used to download a PGP Private Key for a specific user after providing authentication credentials. Clients provide the "id" and "cid" parameter to specify the current user by its user- and context-ID. The "auth" parameter contains a hashed password string which gets created by the client by asking the user to enter his or her OX Guard password. This parameter is used as single point of authentication when accessing PGP Private Keys. In case a user has set the same password as another user, it is possible to download another user's PGP Private Key by iterating the "id" and "cid" parameters. This kind of attack would also be able by brute-forcing login credentials, but since the "id" and "cid" parameters are sequential they are much easier to predict than a user's login name. At the same time, there are some obvious insecure standard passwords that are widely used. A attacker could send the hashed representation of typically weak passwords and randomly fetch Private Key of matching accounts. The attack can be executed by both internal users and "guests" which use the external mail reader.