IBM DB2 Universal Database DB2INSTANCE File Creation Vulnerability
iDefense Security Advisory 02.22.07
Feb 22, 2007
IBM Corp.'s DB2 Universal Database product is a large database server
product commonly used for higher end databases. For more information,
Local exploitation of a file creation vulnerability in IBM Corp.'s DB2
Universal Database could allow attackers to elevate privileges to the
This vulnerability exists due to unsafe file access from within several
setuid-root binaries. Specifically, when supplying the DB2INSTANCE
environment variable, the setuid-root DB2 administration binaries will use
the home directory of the specified user for loading configuration data.
This allows attackers create or append to arbitrary files by creating a
specific executing environment. Additionally, the user's umask settings
will be honored allowing the creation of root-owned world-writable files.
Successful exploitation allows a local attacker to gain root privileges.
It should be noted that the attacker does not appear to have a great deal
of control over the contents of the data written. However, this does not
significantly impact exploitation.
iDefense has confirmed the existence of this vulnerability within IBM
Corp.'s DB2 Universal Database 9.1 release installed on Linux. Other
versions are suspected to be vulnerable as well.
This vulnerability does not affect DB2 Universal Database running on the
The best defense against this type of vulnerability 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
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
#IY94817 by visiting the following URL.
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
The discoverer of this vulnerability wishes to remain anonymous.
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X. LEGAL NOTICES
Copyright =A9 2007 iDefense, Inc.
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the time of publishing based on currently available information. Use of
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