#2015-011 PyAMF input sanitization errors (XXE) Description: PyAMF is a Python module that implements the Action Message Format (AMF) protocol, allowing Flash interoperation with various web frameworks. PyAMF suffers from insufficient AMF input payload sanitization which results in the XML parser not preventing the processing of XML external entities (XXE). A specially crafted AMF payload, containing malicious references to XML external entities, can be used to trigger Denial of Service (DoS) conditions or arbitrarily return the contents of files that are accessible with the running application privileges. Affected version: PyAMF <= 0.7.2 Fixed version: PyAMF >= 0.8.0 Credit: vulnerability reported by Nicolas Grégoire <nicolas [dot] gregoire [at] agarri [dot] fr> CVE: CVE-2015-8549 Timeline: 2015-12-01: vulnerability report received 2015-12-02: contacted maintainer 2015-12-04: maintainer commits patch via public pull request 2015-12-12: reporter confirms patch 2015-12-14: contacted affected vendors 2015-12-14: assigned CVE 2015-12-17: advisory release References: https://github.com/hydralabs/pyamf/pull/58 Permalink: http://www.ocert.org/advisories/ocert-2015-011.html -- Daniele Bianco Open Source Computer Security Incident Response Team <danbia () ocert org> http://www.ocert.org