IBM DB2 Universal Database Directory Traversal Vulnerability

iDefense Security Advisory 08.16.07
http://labs.idefense.com/intelligence/vulnerabilities/
Aug 16, 2007

I. BACKGROUND

IBM Corp.'s DB2 Universal Database product is a large database server
product commonly used for high end databases. For more information,
visit the following URL.

http://ibm.com/db2/

II. DESCRIPTION

Local exploitation of a directory traversal vulnerability in IBM Corp.'s
DB2 Universal Database allows attackers to cause a denial of service
(DoS) condition or elevate privileges to root.

Some DB2 binaries that are installed setuid-root will save event
information to a log file. When creating the full path to the
destination file, an environment variable is concatenated with "/tmp/".
Since there is no checking for path traversal strings, such as "../",
within the environment variable, an attacker is able to create
arbitrary files on the system.

III. ANALYSIS

Exploitation allows local attackers to gain root privileges.

It should be noted that attackers do not appear to have any control over
the contents of the data written. As such, privilege escalation can
occur in combination with a vulnerability that relies on the ability to
create a specially crafted file name. Denying service to the machine is
trivial by writing to /etc/nologin or corrupting other critical system
files.

IV. DETECTION

iDefense confirmed the existence of this vulnerability in version 9.1
Fix Pack 2 of IBM Corp.'s DB2 Universal Database installed on a Linux
system. All prior versions, as well as builds for other UNIX-based
operating systems, are suspected to be vulnerable.

V. WORKAROUND

Setting more strict permissions on the DB2 instance directory can help
mitigate some of these vulnerabilities. Removing the setuid-bit from
all programs included with DB2 can also help mitigate exposure. Note,
these configuration changes have not been thoroughly tested and may
cause adverse behavior.

VI. VENDOR RESPONSE

IBM Corp. has addressed this vulnerability by releasing V9 Fix Pack 3
and version V8 FixPak 15 of its Universal Database product. More
information can be found at the following URLs.

V8: http://www-1.ibm.com/support/docview.wss?uid=swg21256235
V9: http://www-1.ibm.com/support/docview.wss?uid=swg21255572

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-4271 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

03/22/2007  Initial vendor notification
03/23/2007  Initial vendor response
08/16/2007  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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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.

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