Computer Terrorism (UK) :: Incident Response Centre www.computerterrorism.com 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 (UK) ======================== About Computer Terrorism ======================== Computer Terrorism (UK) Ltd is a global provider of Digital Risk Intelligence services. Our unique approach to vulnerability risk assessment and mitigation has helped protect some of the worlds most at risk organisations. Headquartered in London, Computer Terrorism has representation throughout Europe & North America and can be reached at +44 (0) 870 250 9866 or email:- sales [at] computerterrorism.com To learn more about our services and to register for a FREE comprehensive website penetration test, visit: http:/www.computerterrorism.com Computer Terrorism (UK) :: Protection for a vulnerable world.