Microsoft Agent Crafted URL Stack Buffer Overflow
Assurent ID: FSC20070911-11
1. Affected Software
Microsoft Agent, version 18.104.22.16825 (bundled with Windows 2000 Service Pack 4)
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:
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 22.214.171.12425. Earlier versions may also be affected.
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.
7. Disclosure Timeline
04/18/2007 Reported to vendor
04/23/2007 Initial vendor response
09/10/2007 Coordinated public disclosure
Vulnerability Research Team, Assurent Secure Technologies, a TELUS company
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