Unhandled exception in apport

Vulnerability

An unhandled exception in check_ignored() in apport/report.py occurs when the mtime attribute in apport-ignore.xml is a string value instead of a number. This can be triggered by a local attacker. The issue affects Apport versions 2.20.11 and earlier [3]. The flaw is in improper exception handling of the mtime attribute [3].

Exploitation

A local attacker provides a crafted apport-ignore.xml file with a string mtime attribute (e.g., mtime="string"). When Apport processes this file, float(ignore.getAttribute('mtime')) raises a ValueError exception, which is not caught, causing the application to crash. No special privileges are required beyond local access to modify the configuration file [3].

Impact

Successful exploitation results in a denial of service: the Apport service crashes, preventing automatic crash report generation. This disrupts system functionality for crash reporting [1][2][3].

Mitigation

The fix is included in Apport versions 2.20.1-0ubuntu2.24, 2.20.9-0ubuntu7.16, and 2.20.11-0ubuntu27.6 [1][2]. Users should upgrade their apport package to the latest version. There is no known workaround; however, the vulnerability requires local access, so limiting local user trust can mitigate risk.