Oracle Extproc Buffer Overflow (#NISR25072003)

From: NGSSoftware Insight Security Research (nisr_at_NEXTGENSS.COM)
Date: 07/25/03

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    Date:         Fri, 25 Jul 2003 17:05:01 +0100

    NGSSoftware Insight Security Research Advisory

    Name: Oracle Extproc Buffer Overflow
    Systems Affected: Most OS platforms; Oracle9i Database Release 2 and 1, 8i
    Severity: High Risk
    Vendor URL:
    Authors: David Litchfield (
     Chris Anley (
    Date: 25th July 2003
    Advisory number: #NISR25072003

    Oracle's RDBMS, a leading database server package, supports stored packages
    and procedures through the use of PL/SQL. These packages and procedures can
    be extended by allowing calls to be made to operating system libraries. Any
    library loaded in this way is done so by a process external to the main
    RDBMS, namely extproc. Extproc is vulnerable to a classic stack based buffer
    overflow. This can be exploited remotely by an attacker. No user ID or
    password is necessary.

    Previously, NGSSoftware discovered a vulnerability in the Oracle package
    that allowed an attacker to force extproc to load any operating system
    library and execute any function. This attack did not require a user ID or
    password. Oracle took steps to resolve this security hole. By way of fixing
    the vulnerability, attempts to load libraries would be logged but denied
    unless the call came from the local machine. Remote attempts would be logged
    as just stated. However, this logging process is vulnerable to a classic
    stack based buffer overflow vulnerability. By supplying an overly long
    library name a stack based buffer is overflowed, overwriting the saved
    return address on the stack. When the vulnerable procedure returns control
    over the process' path of execution can be gained. As this does not require
    a user ID or password it must be stressed that this is a critical
    vulnerability. On Windows platforms Oracle typically runs in the security
    context of the LOCAL SYSTEM account and, as such, allows for a complete
    compromise of the server. On Unix-based systems extproc runs as the 'Oracle'
    user. As the 'Oracle' user typcially is the owner of the software binaries
    and data files, an attacker exploiting this can completely subvert the
    integrity of the database software and data.

    Fix Information
    NGSSoftware alerted Oracle to this vulnerability on 30th September 2002.
    Oracle has reviewed the code and created a patch which is available from:

    NGSSoftware advise Oracle database customers to review and install the patch
    as a matter of urgency.

    A check for this issue already exists in NGSSQuirreL for Oracle, a
    comprehensive automated vulnerability assessment tool for Oracle Database
    Servers of which more information is available from the NGSSite.

    It is further recommend that Oracle DBAs have their network/firewall
    administrators ensure that the database server is protected from Internet
    sourced traffic.

    About NGSSoftware
    NGSSoftware design, research and develop intelligent, advanced application
    security assessment scanners. Based in the United Kingdom, NGSSoftware have
    offices in the South of London and the East Coast of Scotland. NGSSoftware's
    sister company NGSConsulting, offers best of breed security consulting
    services, specialising in application, host and network security

    Telephone +44 208 401 0070
    Fax +44 208 401 0076

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