Speak Freely <=7.5 multiple remote and local vulnerabilities (the Hackademy Audit)

From: Fozzy (fozzy_at_dmpfrance.com)
Date: 06/07/03

  • Next message: Georgi Guninski: "Re: [Full-Disclosure] public comment period for the Draft Security Vulnerability Reporting and Responding Process (OISAFETY)"
    Date: Sat, 7 Jun 2003 04:46:36 +0200
    To: bugtraq@securityfocus.com, full-disclosure@lists.netsys.com

    --[ Summary ]--

    Speak Freely is a free and open-sourced software used for efficient and
    secure (encrypted) voice communication over the Internet. It was written
    by John Walker, and runs on Windows and Unix. Homepage :

    During a source code audit, the Hackademy staff has found multiple
    serious local and remote security holes in this software.

    --[ Details ]--

    * At least three exploitable stack buffer overflows were found. A single
    UDP packet sent to either the data port(2074/udp) or the control port
    (2075/udp) can crash the sfspeaker program in a way suitable for running
    arbitrary supplied code.

    * Usage of temporary files is insecure, making possible for a malicious
    local user to overwrite with arbitrary data any file owned by the user
    running Speak Freely.

    * Speak Freely has a network feature allowing to send back the same UDP
    packet he received. Because the source IP of an UDP packet can be
    spoofed, there is a potential for relaying malicious packets into a
    protected network (NATed or firewalled) if a computer having access to
    this network is running Speak Freely.

    * There are also a few static buffer overflows, more difficult to exploit.

    --> The text attached to this advisory is taken from the file 'log.doc'
    in the tarball for Speak Freely 7.6-A2, which is immune to most of these
    issues. We also added some technical comments. Read this text for more
    details about the bugs we spotted and how they were adressed.

    --[ Impact ]--

    A remote attacker, as well as a malicious local user, can execute
    arbitrary code on the system with the privileges of the user running
    Speak Freely.
    These are not theoretical issues : we wrote a functional PoC exploit for
    the ADPCM buffer overflow on Linux.

    --[ Vulnerable/Patched Versions ]--

    Speak Freely 7.5 for Unix is vulnerable to all of these issues.
    Speak Freely 7.1 for Windows and Unix (and previous releases) are
    vulnerable to some of these issues.

    Speak Freely 7.6 is patched against most of these issues, and can be
    downloaded here :

    --[ Greetings ]--

    We'd like to thank John Walker for his commitment in taking these issues
    seriously and fixing them quickly.
    Thanks to uzy for helping with the remote tests.

    -- Fozzy

    The Hackademy School, Journal & Audit


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