Software Engineering Institute

The Sky Software FileView object is an ActiveX control that is provided with several applications, such as WinZip. This ActiveX control contains several unsafe methods, but is marked "safe for scripting" and "safe for initialization." For example, some of the methods of this ActiveX control allow an attacker to open, copy, delete, or execute arbitrary files on the target computer.

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 may be able to execute arbitrary commands with the privileges of the user. An attacker may also be able to perform other filesystem activities, such as copying or deleting files.

Apply an update

WinZip 10 users should update to WinZip 10 build 7245. This update provides a version of the FileView control that is not marked "safe for scripting" or "safe for initialization," which means that a web page cannot call the unsafe methods. Versions of WinZip prior to 10 do not appear to contain the vulnerable ActiveX control.

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. 

Disable the FileView object in Internet Explorer

The Sky Software FileView ActiveX controls can be disabled in Internet Explorer by setting the kill bit for the following CLSIDs. Note that this list is not a complete list of the vulnerable controls. Other versions of the FileView ActiveX control may use different CLSIDs.

{0A7A7240-D038-DB9F-B3B1-7FEFFE5F9ED6}
{247D857F-1034-4AA6-BB1A-347D1A3340C8}
{551E5AC9-BDBD-48EC-8AE2-ECAF90C7A214}
{A09AE68F-B14D-43ED-B713-BA413F034904}
More information about how to set the kill bit is available in Microsoft Support Document 240797. Note that Microsoft Security Bulletin MS06-067 sets the kill bit for one of these CLSIDs.