Informix Long Username Buffer Overflow Vulnerability

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 [ [email protected] ]
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

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

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

[email protected]