Software Engineering Institute

The Trend Micro HouseCall ActiveX control (Housecall_ActiveX.dll) includes an update feature. A web page hosting the control can specify update server parameters, and the control does not adequately restrict the type of file or download location. Further details are available from Secunia.

Insecure software update features are a common class of vulnerability, for example, see "Secure Software Updates: Disappointments and New Challenges."

By convincing a user to view a specially crafted HTML document (e.g., a web page or an HTML email message or attachment), an attacker can download an arbitrary file to a location writeable by the user. By writing to a location like a startup directory or a user's desktop, the attacker can increase the chances of the user executing the file.

Install updated version of HouseCall ActiveX control

According to Trend Micro [Hot Fix] B1285, sites running HouseCall should "Request the HouseCall 6.6 Hot Fix Build 1285 file from Trend Micro Technical Support."

Trend Micro [Hot Fix] B1285 states that "The public HouseCall Server 6.6 has been patched." Examination of the free online HouseCall web site (as of 2008-12-24) shows that visitors are directed to a URL that indicates HouseCall version 6.5 and provided with a vulnerable version (6.51.0.1028) of the ActiveX control. According to Secunia, users should remove existing versions of the control and install version 6.6.0.1285 from http://prerelease.trendmicro-europe.com/hc66/launch/.

Disable the HouseCall ActiveX control in Internet Explorer

The vulnerable ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSIDs:

{215B8138-A3CF-44c5-803F-8226143CFC0A}
{6E5A37BF-FD42-463A-877C-4EB7002E68AE}
More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{215B8138-A3CF-44c5-803F-8226143CFC0A}]
"Compatibility Flags"=dword:00000400

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX Compatibility\{6E5A37BF-FD42-463A-877C-4EB7002E68AE}]
"Compatibility Flags"=dword:00000400
Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document.