CVE-2017-8761

Vulnerability

In OpenStack Swift, the proxy-server logs complete temporary URL (tempurl) paths, including the signatures that authenticate access. This affects all versions through 2.10.1, 2.11.0 through 2.13.0, and 2.14.0 that use the tempurl middleware [1]. The signatures are reusable if they have not expired.

Exploitation

An attacker needs read access to the proxy-server logs to extract the full tempurl paths containing signatures. This can be achieved through log file exposure, log aggregation systems, or insider access. With the signature, the attacker can then access the resource protected by that tempurl without further authentication [2].

Impact

Successful exploitation allows unauthorized access to data protected by tempurls. If the tempurl has a long validity period, the attacker may repeatedly access the resource. This compromises the confidentiality of the stored data.

Mitigation

The vulnerability is fixed in Swift version 2.15.0 and later [2]. Users should upgrade to the latest supported release. As a temporary workaround, restrict access to proxy-server logs and use short-lived tempurls to limit the window of exposure.