Public Vulnerability Reports

IBM Informix Dynamic Server DBLANG Directory Traversal Vulnerability



IBM Corp.'s Informix Dynamic Server is an online transaction processing data server. It contains several set-uid root binaries. For more information, visit the product homepage at the following URL.


Local exploitation of a directory traversal vulnerability in IBM Corp.'s Informix Dynamic Server allows attackers to elevate privileges to root.

This vulnerability exists due to insufficient checking for directory traversal sequences when processing the DBLANG environment variable. By using values containing directory traversal specifiers, such as "../", an attacker can cause set-uid binaries to use Native Language Support (NLS) message files under their control.


Exploitation allows local attackers to gain root privileges. In order to exploit this vulnerability, an attacker would need access to execute one of the set-uid root binaries that utilizes the DBLANG environment variable.

Since an attacker can control NLS message file data, they are able to pass arbitrary format string arguments to the variable argument function printf(3). Consequently, this vulnerability can be exploited using publicly known format string exploitation techniques.

When attempting to exploit this vulnerability, it is likely that an attacker would try to execute code within area of memory that are considered data. As such, NX, XD, exec-shield, PAX and other data execution prevention technologies can decrease the likelihood of success.


iDefense confirmed the existence of this vulnerability in IBM Corp.'s Informix Dynamic Server version 10.00 UC6TL installed on a Linux system. Other versions are also suspected as vulnerable. Versions for other supported Unix systems should also be considered vulnerable.


Removing the set-uid bit from all programs included with Informix will prevent exploitation. However, doing so may also disable functionality.


IBM Corp. has addressed this vulnerability within version 10.00.xC7W1 of Informix Dynamic Server. For more information, visit the following URL.


The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2007-5670 to this issue. This is a candidate for inclusion in the CVE list (, which standardizes names for security problems.


09/01/2007 Initial vendor notification
09/13/2007 Initial vendor response
11/06/2007 IBM Released 10.00.xC7W1
11/09/2007 Public disclosure


The discoverer of this vulnerability wishes to remain anonymous.

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Copyright © 2007 Verisign, Inc.

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