Has Your Computer Been Hijacked?

Defend Yourself Against Computer Hijacking

Police in Spain have just reported the arrest of three men thought to be responsible for the Mariposa Botnet, a network of almost 13 million virus-infected computers. Mariposa infected and hijacked computers around the world -- in corporations, government agencies, schools, and private homes.

Mariposa initially spread by way of a bug in the Internet Explorer browser, and those affected were subject to silent keystroke monitoring that resulted in the theft of online banking login credentials and credit card numbers. Computers caught up in the botnet could also be "rented" to other hackers for the purpose of sending spam or participating in denial of service attacks.

Could your computer be hijacked? Imagine the police asking you why you downloaded child pornography. You say you didn't, of course. But there it is on your hard drive, courtesy of a hijacker who used your computer to download and distribute the stuff. It can be very difficult and expensive to prove that you didn't do it.

Despite security software, it's always possible to be hijacked. Bad guys are constantly waging a war of escalation with security software makers, and it just might be your "lucky day" to be attacked by a hijacker with a technique your security software provider hasn't heard of yet. How can you tell if your computer has been hijacked, and liberate it before it is used to cause trouble for you and others?

How Can I Tell if My Computer Has Been Hijacked?

Hijackers often attack via unpatched security holes in your Internet browser, and download malicious programs to your hard drive. Symptoms of this sort of hijacking include inexplicable changes to your home page; incessant pop-up ads; or being re-directed to some unwanted site whenever you click on a link that you want to open. You may also notice that your computer or Internet connection is slower than usual.

The sudden appearance of new browser toolbars is also a cause for alarm. Often, free applications offered online include extra "goodies" like toolbars that supposedly do you good. But the toolbars can hide software that turns your computer into a tool of hackers, spammers, identity thieves, and porn distributors.

Email is another avenue by which bad guys inject hijacking software into your computer. If your email program suddenly starts sending out messages without your assistance, it's probably been hijacked. Unfortunately, you might only find out about this when you get a flood of angry emails from people asking why you sent them spammy or scammy emails.

Protect and Defend Against Hijacking

Keeping your operating system up to date with the latest security patches is crucial to staying safe online. Use the tools built into your operating system -- Windows Update, Mac OS X Software Update, or the equivalent on your Linux system -- and configure them to download and install fixes automatically. Application software packages that you've installed may also offer automatic updating capability.

You should also run a full anti-malware scan of your entire system if you spot signs of hijacking. Heck, even if you don't spot any signs, you should STILL run virus and spyware scans regularly. And you don't have to spend a lot of money on computer security tools. Check out my list of Free Anti-Virus Programs and Free Anti-Spyware Programs for starters.

Also consider using security software such as PCTools ThreatFire which looks for suspicious behavior of software and fingers it as potential malware. This broader approach can catch hijacking applications that are not yet known to other security tools which use a signature-based approach to detect known malware.

A hijacked computer can steal your personal information; spam everyone you know and millions of people you don't know; it can be used to commit crimes like child porn distribution or denial-of-service attacks; and generally wreak havoc with your life and those of others. Be alert to the symptoms of hijacking, and take all the precautions you can to prevent it.

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