[Full-disclosure] Computer Terrorism (UK) :: Incident Response Centre - Microsoft Publisher Font Parsing Vulnerability

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Security Advisory: CT12-09-2006-2.htm


==============================================
Microsoft Publisher Font Parsing Vulnerability
==============================================

Advisory Date: 12th, September 2006

Severity: Critical
Impact: Remote System Access
Solution Status: Vendor Patch

CVE Reference:  CVE-2006-0001


Affected Software
=================

Microsoft Publisher 2000 (Office 2000)
Microsoft Publisher 2002 (Office 2002)
Microsoft Publisher 2003 (Office 2003)



1. OVERVIEW
===========

Microsoft Publisher is a lightweight desktop publishing (DTP) application 
bundled with Microsoft Office Small Business and Professional. The 
application facilitates the design of professional business and marketing 
communications via familiar Office tools & functionality.

Unfortunately, it transpires that Microsoft Publisher is susceptible to a 
remote, arbitrary code execution vulnerability that yields full system 
access running in the context of a target user.



2. TECHNICAL NARRATIVE
======================

The vulnerability emanates from Publishers inability to perform sufficient 
data validation when processing the contents of a .pub document. As a 
result, it is
possible to modify a .pub file in such a way that when opened will corrupt 
critical system memory, allowing an attacker to execute code of his choice.

More specifically, the vulnerable condition is derived from an attacker 
controlled string that facilitates an "extended" memory overwrite using 
portions of the original
.pub file.

As no checks are made on the length of the data being copied, the net result 
is that of a classic "stack overflow" condition, in which EIP control is 
gained via one of several return addresses.


3. EXPLOITATION
===============

As with most file orientated vulnerabilities, the aforementioned issue 
requires a certain degree of social engineering to achieve successful 
exploitation.

However, users of Microsoft Publisher 2000 (Office 2000) are at an increased 
risk due to the exploitability of the vulnerability in a possible web-based 
attack scenario.



4. VENDOR RESPONSE
==================

The vendor security bulletin and corresponding patches are available at the 
following location:

http://www.microsoft.com/technet/security/Bulletin/MS06-054.mspx


5. DISCLOSURE ANALYSIS
======================

03/08/2005  Preliminary Vendor notification.
12/08/2005  Vulnerability confirmed by Vendor.
03/01/2006  Public Disclosure Deferred by Vendor.
11/07/2006  Public Disclosure Deferred by Vendor.
12/09/2006  Coordinated public release.

Total Time to Fix: 1 year, 1 month, 6 days (402 days)


6. CREDIT
=========

The vulnerability was discovered by Stuart Pearson of Computer Terrorism

========================
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========================

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