NGSSoftware Insight Security Research Advisory

Name: Informix Long Username Buffer Overflow Vulnerability
Systems Affected: Informix 9.40.xC6 and earlier, 10.00.xC2 and earlier
Severity: Critical
Vendor URL: http://www.ibm.com/ 
Author: David Litchfield [ davidl@ngssoftware.com ] 
Date of Public Advisory: 2nd August 2006
Advisory number: #NISR02082006A
CVEID: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2006-3853 
Advisory URL: http://www.ngssoftware.com/research/ 

Description
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Informix Dynamic Server is a database developed by IBM. During a security 
assessment of the database it was found to be vulnerable to a stack based 
buffer overflow in the authentication procedure.

Details
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When an Informix server logs on a user it copies the username to a 260 byte 
stack based buffer without first verifying its length. An attacker can 
exploit this by overflowing this buffer to overwrite the saved return 
address on the stack and thus redirect the process' path of execution to a 
location of their choosing.

Whilst the IBM advisory indicates that only Informix running on Windows is 
vulnerable to this NGS we're able to determine that Informix running on 
Linux is also vulnerable.

Fix Information
***************
IBM was alerted to this flaw on the 6th January 2005; a fix has now been 
made available. IBM's advisory on the matter can be found here: 
http://www-1.ibm.com/support/docview.wss?uid=swg21242921 

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 
http://www.ngssoftware.com/products/database-security/ngs-squirrel-informix.php 

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.

http://www.ngssoftware.com/ 

Telephone +44 208 401 0070
Fax +44 208 401 0076

enquiries@ngssoftware.com