CVE-2013-7489

Vulnerability

Overview

The Beaker library for Python, through version 1.11.0, is vulnerable to deserialization of untrusted data (CWE-502) [1]. The flaw resides in the Cache layer, where Python's pickle module is used to serialize and deserialize cached data without integrity verification [2][4]. This allows an attacker who can write to the cache backend to inject a malicious pickle payload that, when later retrieved, will be deserialized into arbitrary Python objects, leading to code execution on the Beaker host [3][4].

Exploitation

Exploitation requires the attacker to have write access to the Beaker cache database, for example by being on the same network and possessing database credentials [4]. The Session component was previously hardened with HMAC signing, but the Cache layer remained unprotected, making it the attack vector [2][4]. No authentication is needed beyond access to the cache backend; the deserialization happens automatically when cached data is fetched [4].

Impact

Successful exploitation results in remote code execution on the server running Beaker, as the attacker-controlled pickle object is deserialized and executed within the Python interpreter of the application [1][3][4]. This can lead to full compromise of the affected system, including data theft, further lateral movement, and persistent access.

Mitigation

As of the advisory publication, no patch was available, but the maintainer suggested implementing data signing for cache entries [4]. Mitigation steps include restricting network access to the cache database, enforcing strong authentication for cache backends, and potentially avoiding the use of Beaker's Cache functionality if not needed [4]. The flaw affects all versions through 1.11.0; users should monitor for an official fix and apply it when released.