IBM DB2 JDBC Applet Server buffer overflow (#NISR05012005D)

From: NGSSoftware Insight Security Research (nisr_at_NEXTGENSS.COM)
Date: 01/05/05

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    Date:         Wed, 5 Jan 2005 17:50:35 -0000
To: NTBUGTRAQ@LISTSERV.NTBUGTRAQ.COM

    NGSSoftware Insight Security Research Advisory

    Name: IBM DB2 JDBC Applet Server buffer overflow
    Systems Affected: DB2 8.1
    Severity: High risk from remote
    Vendor URL: http://www.ibm.com/
    Author: David Litchfield [ david at ngssoftware.com ]
    Relates to: http://www.nextgenss.com/advisories/db2-02.txt
    Date of Public Advisory: 5th January 2005
    Advisory number: #NISR05012005D
    Advisory URL: http://www.ngssoftware.com/advisories/db205012005D.txt

    Description
    ***********
    IBM's DB2 JDBC Applet Server suffers from a stack based buffer overflow
    vulnerability that can be exploited remotely without a user ID or password.

    Details
    *******
    When a client connects to the JDBC applet server on TCP port 6789 it does so
    using a proprietary protocol. The connection packet starts with
    ValidDb2jdTokenFromTheClientSide and includes the username, the password,
    the db2java.zip version and the database to connect to.

    The problem arises as follows.

    Firstly, an attacker attempts to authenticate to the JDBC applet server on
    TCP 6789 with an overly long username of c. 2200 bytes then disconnects
    gracefully.

    Secondly, they reconnect, but this time send a short username but set the
    db2java.zip version to something other than expected by the server. Set the
    version to c. 544 unicode bytes \x00\x41.

    An error is logged and at some stage the null terminator is removed and the
    original username that was sent is concatentated to the db2java.zip version.

    This is then copied to a stack based buffer and it overflows.

    Fix Information
    ***************
    IBM has written a patch and can be obtained with the latest fixpak.

    http://www-306.ibm.com/software/data/db2/udb/support/downloadv8.html - DB2
    v8.1
    http://www-306.ibm.com/software/data/db2/udb/support/downloadv7.html - DB2
    v7.x

    NGSSQuirreL for DB2 (http://www.nextgenss.com/db2.htm) can be used to assess
    whether your DB2 server is vulnerable to this.

    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
    assessments.

    http://www.ngssoftware.com/

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

    enquiries@ngssoftware.com 

    --
NTBugtraq Editor's Note:
Most viruses these days use spoofed email addresses. As such, using an Anti-Virus product which automatically notifies the perceived sender of a message it believes is infected may well cause more harm than good. Someone who did not actually send you a virus may receive the notification and scramble their support staff to find an infection which never existed in the first place. Suggest such notifications be disabled by whomever is responsible for your AV, or at least that the idea is considered.
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