CVE-2015-8542: An issue was discovered in Open-Xchange Guard before 2.2.0-rev8.

An issue was discovered in Open-Xchange Guard before 2.2.0-rev8.

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

Description from the National Vulnerability Database, published by MITRE

What it means for a small business

If your business uses OX Guard, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 2.2%, higher than 82% of CVEs. That’s above average: worth scheduling this week. Scored October 29, 2026, updated daily.

Check your own setup

Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
Server check: what your web server says about itself, and whether that version has known flaws.

Sources

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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