Advisory Text :  

Microsoft Agent Crafted URL Stack Buffer Overflow

Assurent ID: FSC20070911-11

1. Affected Software

Microsoft Agent, version 2.0.0.3425 (bundled with Windows 2000 Service
Pack 4)

Reference: http://www.microsoft.com/msagent/

2. Vulnerability Summary

The Microsoft Agent ActiveX control contains a buffer overflow
vulnerability that allows remote attackers to inject and execute
arbitrary code with the privileges of the currently logged in user.

The affected ActiveX control is registered as below:

File: agentdpv.dll
ProgID: Agent.Control
CLASSID: D45FD31B-5C6E-11D1-9EC1-00C04FD7081F

3. Vulnerability Analysis

The target user is enticed to view a malicious web page. The script in
the web page calls a method of the affected ActiveX control with
malicious arguments. A stack-based buffer will be overrun upon
processing the malicious script.

Assurent has confirmed that code execution is possible. The code in such
a case would execute within the security context of the currently logged
in user.

In an attack case where code injection is not successful, the affected
application will terminate abnormally.

Note that although this vulnerability is exploited through Internet
Explorer, the affected application is the Microsoft Agent application.

4. Vulnerability Detection

Assurent has confirmed the vulnerability in Microsoft Agent shipped with
Windows 2000 SP4. The confirmed vulnerable file version is 2.0.0.3425.
Earlier versions may also be affected.

5. Workaround

Setting the kill bit for the vulnerable ActiveX control's CLSID will
prevent this issue from being exploited via Internet Explorer.

6. Vendor Response

Microsoft has released a bulletin addressing this vulnerability as part
of the September 2007 update cycle.
Reference:
http://www.microsoft.com/technet/security/bulletin/ms07-051.mspx

7. Disclosure Timeline

04/18/2007 Reported to vendor
04/23/2007 Initial vendor response
09/10/2007 Coordinated public disclosure

8. Credits

Vulnerability Research Team, Assurent Secure Technologies, a TELUS
company

9. References

CVE: CVE-2007-3040
Vendor: MS07-051

10. About Assurent VRS

Assurent's Vulnerability Research Service (VRS) for security product
vendors, and Threat Protection Programs (TPP) for MSPs and enterprise
security teams, help to eliminate the significant costs incurred by
security product vendors, MSPs, and enterprise security teams in
responding to and managing critical new security vulnerabilities and
other threats including worm & virus outbreaks and high-risk spyware.
The VRS and TPP services are real-time feeds providing subscribers with
detailed analysis of the top security vulnerabilities, focused on the
specific needs of each group of customers.

http://www.assurent.com/