Assurent VR - Microsoft Agent Crafted URL Stack Buffer Overflow

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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


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