Arbitrary Library Loading in Informix

NGSSoftware Insight Security Research Advisory

Name: Arbitrary Library Loading in Informix
Systems Affected: All versions of Informix
Severity: High
Vendor URL:
Author: David Litchfield [ davidl@xxxxxxxxxxxxxxx ]
Date of Public Advisory: 2nd August 2006
Advisory number: #NISR02082006C
Advisory URL:

Informix Dynamic Server is a database developed by IBM. An attacker can force to the database server to load an arbitrary library and thus execute arbitrary code.

The ifx_load_internal SQL function can be used to load an arbitrary library into the address space of the database server process. By placing code in the DllMain() function on Windows or _init() on Linux an attacker can have this code execute automatically when the library is loaded. In conjunction with exploiting other flaws it is possible to remotely create a library over SQL, dump this to the server disk and then load it.

Fix Information
IBM was alerted to this flaw on the 18th January 2005. Revoking execute permission on ifx_load_internal SQL function from public will remove the risk of exploitation of this issue.

NGSSQuirreL for Informix, an advanced vulnerability assessment scanner designed specifically for Informix, can be used to accurately determine whether your servers are vulnerable to this flaw. More information about NGSSQuirreL for Informix can be found here

About NGSSoftware

NGSSoftware develops vulnerability assessment and compliancy tools for database servers including Oracle, Microsoft SQL Server, DB2, Sybase and Informix. Headquartered in the United Kingdom NGS has offices in London, St. Andrews (UK), Sydney, Brisbane, and Perth (Australia) and Texas in the United States; NGSConsulting provide services to some of the largest and most demanding organizations around the globe.

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