Two Tenacious Exploits Debunk Vendor Claims
Many sandbox security vendors claim that their products stop all known and unknown attacks. Even assuming the ability to curtail all known attacks could be proven, it's simply impossible to believe that any piece of software could halt all unknown attacks. Of course, that doesn't prevent the vendors from making empty promises or the malware authors from proving them wrong.
In my testing of five sandbox security clients -- Authentium's SafeCentral, Check Point's ZoneAlarm ForceField, Prevx, Sandboxie, and SoftSphere Technologies' DefenseWall HIPS -- I exposed all the products to dozens of malicious attacks, both well known and not so well known. Two malware programs, in particular, stretched the various competitors to their breaking points: the Adobe Flash clipboard hijack exploit and the XP Antivirus malware program.
The Adobe Flash clipboard hijack is an example of a cross-platform, cross-browser exploit. The exploit was first reported in the middle of August, when it started showing up on legitimate Web sites innocently hosting malicious banner ads. It works against Internet Explorer, Firefox, Safari, and other browsers capable of running Adobe's Macromedia Flash plug-in. When activated, the clipboard hijack writes persistent data to the user's clipboard (that is, the edit-copy, edit-paste buffer). Even users with fully patched systems and the latest browsers had their clipboards hijacked.
The Adobe Flash clipboard hijack deposits a malicious URL on the user's clipboard so that every time the user pastes content, they end up pasting the bogus link instead of -- or in addition to -- their intended content. The idea is to trick the user into clicking on the link or inadvertently posting it in blog comments and the like.
For my product testing, I used a safe demo of the exploit. When you run it, the text www.evil.com is pasted to your clipboard. To remove it, you must close the browser session and copy some new text to your clipboard. In some cases, you may have to reboot your computer to get rid of the hijacking.
I used this clipboard hijack demo attack to see how well the reviewed products could defend against a relatively unexpected attack vector. The clipboard hijack was especially difficult to defend because it used multiple applications to do its dirty work and did not modify any files. As I expected, none of the products prevented this attack.
Another major threat going around these days is known as the XP Antivirus 2008 exploit and a few similar names. A user is socially engineered into installing a bogus anti-virus program, which then detects thousands of malicious viruses and prompts the user to buy the program to get rid of the malware. Not surprisingly, often the only malware program truly installed on the system is the XP Antivirus 2008 program itself.
The interesting feature of this malware program is its ability to modify the Microsoft Windows desktop to look as if the status bar is sending an alert message indicating a virus infection. The alert looks like an official Microsoft Windows warning, bubbling up from the area where you normally expect to see legitimate programs. The XP Antivirus 2008 program install looks just as official, but once installed, the program either asks for money to get rid of the supposed viruses or starts stealing confidential information. By the time most users realize they have been scammed, it's too late.
The Internet is full of sites and tools attempting to help users disinfect their PCs. Most solutions don't work no matter how well intended. Many malicious executables are programmed to prevent easy cleanup, even blocking access to Web sites that offer good help and preventing legitimate cleanup tools from running. My friend, Jesper Johansson, provides a great, detailed profile of the XP Antivirus malware scam.
I use the XP Antivirus malware in my testing not only to see if the reviewed product could defend against it, but also because XP Antivirus is one of the most difficult exploits to remove. The sophisticated coding invades multiple areas of the system, disables popular anti-virus programs, turns off firewalls, and does its best to remain on the system, even when you think the system has been cleaned.
Sure enough, some of the reviewed products don't do a perfect job of removing XP Antivirus, which means there are cracks in the armor that can be exploited by other malware.