IBM DB2 Universal Database Multiple Privilege Escalation Vulnerabilities

iDefense Security Advisory 02.22.07
https://labs.idefense.com/intelligence/vulnerabilities/
Feb 22, 2007

I. BACKGROUND

IBM Corp.'s DB2 Universal Database product is a large database server
product commonly used for higher end databases. For more information,
visit https://ibm.com/db2/

II. DESCRIPTION

Local exploitation of a multiple vulnerabilities in IBM Corp.'s DB2
Universal Database allow attackers to cause a denial of service condition
or elevate privileges to root.

Several vulnerabilities exist due to unsafe file access from within
several setuid-root binaries. Specifically, when supplying certain
environment variables, the DB2 administration binaries will use the
specified filename for saving data. This allows an attacker to create or
append to arbitrary files as root.

A heap-based buffer overflow vulnerability can occur when copying data
from an environment variable. The variable contents are copied to a static
BSS segment buffer without ensuring proper NUL termination. Consequently,
this allows an attacker to cause a heap overflow in a later function call.

A stack-based buffer overflow can occur when an environment variable
contains a long string. By specifying a specially crafted value, it is
possible to overwrite the return address of a function and execute
arbitrary code.

III. ANALYSIS

Successful exploitation allows a local attacker to cause a denial of
service condition or potentially gain root privileges.

In some cases, the attacker does not appear to have any control over the
contents of the data written to disk. If this is true, then privilege
escalation
could only occur via another bug where the existence of specially
crafted file
name allows code execution. Denial of service is trivial by writing to
/etc/nologin or corrupting other system files.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities within IBM
Corp.'s DB2 Universal Database 9.1 release installed on Linux. Other
versions, including those installed on other architectures, are suspected
to be vulnerable as well.

These vulnerabilities do not appear to affect DB2 Universal Database
running on the windows platform.

V. WORKAROUND

The best defense against these vulnerabilities is to prevent untrusted
users from having code execution abilities on the respective database
server. The following workarounds also have value.

Use a more strict permissions setting for the DB2 instance directory would
prevent non-instance users from accessing the setuid-root binaries.

Remove the setuid bit from all programs included with DB2.

These configuration changes have not been tested and may cause adverse
behavior.

VI. VENDOR RESPONSE

IBM Corp. has addressed this vulnerability within IBM Universal Database
DB2 9 Fixpack 2. For more information, consult the corresponding IBM APAR
#IY94833 by visiting the following URL.

https://www-1.ibm.com/support/docview.wss?uid=swg21255747

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

11/15/2006  Initial vendor notification
01/29/2007  Initial vendor response
02/22/2007  Coordinated public disclosure

IX. CREDIT

These vulnerabilities were discovered by Joshua J. Drake (iDefense Labs).

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X. LEGAL NOTICES

Copyright © 2007 iDefense, Inc.

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Disclaimer: The information in the advisory is believed to be accurate at
the time of publishing based on currently available information. Use of
the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on, this
information.