[UNIX] Libneon Date Parsing Vulnerability

From: SecuriTeam (support_at_securiteam.com)
Date: 05/19/04

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    To: list@securiteam.com
    Date: 19 May 2004 15:25:48 +0200

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      Libneon Date Parsing Vulnerability


     <http://www.webdav.org/neon> neon is "an HTTP and WebDAV client library,
    with a C interface". A vulnerability within a libneon date parsing
    function could cause a heap overflow that could lead to remote code
    execution, depending on the application using libneon. OpenOffice and
    Subversion *DO NOT* use this function and are therefore not vulnerable to
    THIS problem.


    Vulnerable Systems:
     * libneon version 0.24.5 and prior

    While scanning the libneon source code for common programming errors an
    unsafe usage of sscanf() was discovered within one of the date parsing
    When a special crafted date string is passed to the ne_rfc1036_parse() it
    may trigger a sscanf() string overflow into static heap variables.
    Exploitability heavily depends on the application linked against neon but
    is considered trivial in cases where an out-of-memory condition can be
    triggered, because the overflowing variable is placed in front of the
    libneon out-of-memory callback function pointer.
    Please notice that your application could be vulnerable even if you do not
    use ne_rfc1036_parse() directly, because its functionality is used by
    several higher level API functions.

    Disclosure Timeline:
    02. May 2004 - Neon developers were contacted by email
    04. May 2004 - Joe Orton has fixed the bug within neon and waits for the
    public disclosure date
    19. May 2004 - Coordinated Public Disclosure
    CVE Information:

    Because Subversion and OpenOffice, which are the most important libneon
    users, are not using the vulnerable function the issue is rated with a
    medium severity. Nevertheless upgrading your neon version is recommended
    because other applications could be vulnerable and could expose the
    vulnerable function to the outside world.


    The information has been provided by <mailto:s.esser@e-matters.de> Stefan

    The original article can be found at:


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