By Roger A. Grimes
Redirected Net searches, unexpected installs, rogue mouse pointers: Here’s what to do when you’ve been 0wned
In today’s threatscape, antivirus software provides little piece of mind. In fact, antimalware scanners on the whole are horrifically inaccurate, especially with exploits less than 24 hours old. After all, malicious hackers and malware can change their tactics at will. Swap a few bytes around, and a previously recognized malware program becomes unrecognizable.
To combat this, many antimalware programs monitor program behaviors, often called heuristics, to catch previously unrecognized malware. Other programs use virtualized environments, system monitoring, network traffic detection, and all of the above at once in order to be more accurate. And still they fail us on a regular basis.
Here are 11 sure signs you’ve been hacked and what to do in the event of compromise. Note that in all cases, the No. 1 recommendation is to completely restore your system to a known good state before proceeding. In the early days, this meant formatting the computer and restoring all programs and data. Today, depending on your operating system, it might simply mean clicking on a Restore button. Either way, a compromised computer can never be fully trusted again. The recovery steps listed in each category below are the recommendations to follow if you don’t want to do a full restore — but again, a full restore is always a better option, risk-wise.
Sure sign of system compromise No. 1:
Fake antivirus messages
In slight decline these days, fake antivirus warning messages are among the surest signs that your system has been compromised. What most people don’t realize is that by the time they see the fake antivirus warning, the damage has been done. Clicking No or Cancel to stop the fake virus scan is too little, too late. The malicious software has already made use of unpatched software, often the Java Runtime Environment or an Adobe product, to completely exploit your system.
WHAT TO DO: As soon as you notice the fake antivirus warning message, power down your computer. (Note: This requires knowing what your legitimate antivirus program’s warning looks like.) If you need to save anything and can do it, do so. But the sooner you power off your computer, the better. Boot up the computer system in Safe Mode, No Networking, and try to uninstall the newly installed software (oftentimes it can be uninstalled like a regular program).
Sure sign of system compromise No. 2:
Unwanted browser toolbars
This is probably the second most common sign of exploitation: Your browser has multiple new toolbars with names that seem to indicate the toolbar is supposed to help you. Unless you recognize the toolbar as coming from a very well-known vendor, it’s time to dump the bogus toolbar.
WHAT TO DO: Most browsers allow you to review installed and active toolbars. Remove any you didn’t absolutely want to install. When in doubt, remove it. If the bogus toolbar isn’t listed there or you can’t easily remove it, see if your browser has an option to reset the browser back to its default settings.
Sure sign of system compromise No. 3:
Redirected Internet searches
Many hackers make their living by redirecting your browser somewhere other than you want to go. The hacker gets paid by getting your clicks to appear on someone else’s website, often those who don’t know that the clicks to their site are from malicious redirection.
You can often spot this type of malware by typing a few related, very common words (for example, “puppy” or “goldfish”) into Internet search engines and checking to see whether the same websites appear in the results — almost always with no actual relevance to your terms.
WHAT TO DO: Follow the same instructions as above. Usually removing the bogus toolbars and programs is enough to get rid of malicious redirection.
Sure sign of system compromise No. 4:
Frequent random popups
This popular sign that you’ve been hacked is also one of the more annoying ones. When you’re getting random browser pop-ups from websites that don’t normally generate them, your system has been compromised.
WHAT TO DO: Not to sound like a broken record, but typically random pop-ups are generated by one of the three previous malicious mechanisms noted above. You’ll need to get rid of bogus toolbars and other programs if you even hope to get rid of the pop-ups.
Sure sign of system compromise No. 5:
Your friends receive fake emails from your email account
This is the one scenario where you might be OK. It’s fairly common for our email friends to receive malicious emails from us. A decade ago, when email attachment viruses were all the rage, it was very common for malware programs to survey your email address book and send malicious emails to everyone in it.
WHAT TO DO: If one or more friends reports receiving bogus emails claiming to be from you, do your due diligence and run a complete antivirus scan on your computer, followed by looking for unwanted installed programs and toolbars. Often it’s nothing to worry about, but it can’t hurt to do a little health check when this happens.
Sure sign of system compromise No. 6:
Your online passwords suddenly change
If one or more of your online passwords suddenly change, you’ve more than likely been hacked — or at least that online service has been hacked. In this particular scenario, usually what has happened is that the victim responded to an authentic-looking phish email that purportedly claimed to be from the service that ends up with the changed password. The bad guy collects the logon information, logs on, changes the password (and other information to omplicate recovery), and uses the service to steal money from the victim or the victim’s acquaintances (while pretending to be the victim).
WHAT TO DO: If the scam is widespread and many acquaintances you know are being reached out to, immediately notify all your contacts about your compromised account. Do this to minimize the damage being done to others by your mistake. Second, contact the online service to report the compromised account.
If the compromised logon information is used on other websites, immediately change those passwords. And be more careful next time. Websites rarely send emails asking you to provide your logon information.
Sure sign of system compromise No. 7:
Unexpected software installs
Unwanted and unexpected software installs are a big sign that your computer system has likely been hacked.
In the early days of malware, most programs were computer viruses, which work by modifying other legitimate programs. They did this to better hide themselves. For whatever reason, most malware programs these days are Trojans and worms, and they typically install themselves like legitimate programs. This may be because their creators are trying to walk a very thin line when the courts catch up to them.
WHAT TO DO: There are many free programs that show you all your installed programs and let you selectively disable them. My favorite for Windows is Autoruns. It doesn’t show you every program installed but will tell you the ones that automatically start themselves when your PC is restarted. Most malware programs can be found here.
Sure sign of system compromise No. 8:
Your mouse moves between programs and makes correct selections
If your mouse pointer moves itself while making selections that work, you’ve definitely been hacked. Mouse pointers often move randomly, usually due to hardware problems. But if the movements involve making the correct choices to run particular programs, malicious humans are somewhere involved.
WHAT TO DO: If your computer “comes alive” one night, take a minute before turning it off to determine what the intruders are interested in. Don’t let them rob you, but it will be useful to see what things they are looking at and trying to compromise. If you have a cellphone handy, take a few pictures to document their tasks. When it makes sense, power off the computer. Unhook it from the network (or disable the wireless router) and call in the professionals. This is the one time that you’re going to need expert help.
Sure sign of system compromise No. 9:
Your antimalware software, Task Manager, or Registry Editor is disabled and can’t be restarted
This is a huge sign of malicious compromise. If you notice that your antimalware software is disabled and you didn’t do it, you’re probably exploited — especially if you try to start Task Manager or Registry Editor and they won’t start, start and disappear, or start in a reduced state. This is very common for malware to do.
WHAT TO DO: You should really perform a complete restore because there is no telling what has happened. But if you want to try something less drastic first, research the many methods on how to restore the lost functionality (any Internet search engine will return lots of results), then restart your computer in Safe Mode and start the hard work. I say “hard work” because usually it isn’t easy or quick.
Sure sign of system compromise No. 10:
Your bank account is missing money
I mean lots of money. Online bad guys don’t usually steal a little money. They like to transfer everything or nearly everything, often to a foreign exchange or bank. Usually it begins by your computer being compromised or from you responding to a fake phish from your bank. In any case, the bad guys log on to your bank, change your contact information, and transfer large sums of money to themselves.
WHAT TO DO: In most cases you are in luck because most financial institutions will replace the stolen funds (especially if they can stop the transaction before the damage is truly done). However, there have been many cases where the courts have ruled it was the customer’s responsibility to not be hacked, and it’s up to the financial institution to decide whether they will make restitution to you.
If you’re trying to prevent this from happening in the first place, turn on transaction alerts that send text alerts to you when something unusual is happening.
Sure sign of system compromise No. 11:
You get calls from stores about nonpayment of shipped goods
In this case, hackers have compromised one of your accounts, made a purchase, and had it shipped to someplace other than your house. Oftentimes, the bad guys will order tons of merchandise at the same time, making each business entity think you have enough funds at the beginning, but as each transaction finally pushes through you end up with insufficient funds.
WHAT TO DO: This is a bad one. First try to think of how your account was compromised. If it was one of the methods above, follow those recommendations. Either way, change all your logon names and passwords (not just the one related to the single compromised account), call law enforcement, get a case going, and start monitoring your credit.
Malware vector trifecta to avoid
The hope of an antimalware program that can perfectly detect malware and malicious hacking is pure folly. Keep an eye out for the common signs and symptoms of your computer being hacked as outlined above. And if you are risk-adverse, as I am, always perform a complete computer restore with the event of a breach. Because once your computer has been compromised, the bad guys can do anything and hide anywhere. It’s best to just start from scratch.
Most malicious hacking originates from one of three vectors: unpatched software, running Trojan horse programs, and responding to fake phishing emails. Do better at preventing these three things, and you’ll be less likely to have to rely on your antimalware software’s accuracy — and luck.
Roger A. Grimes is contributing editor of the InfoWorld Test Center. Roger holds over 40 computer certifications and has authored eight books on computer security. He has been fighting malware and malicious hackers since 1987, beginning with disassembling early DOS viruses. He currently runs eight honeypots to track hacker and malware behavior and consults to companies from the Fortune 100 to small businesses. A frequent industry speaker and educator, Roger currently works for Microsoft as a Principal Security Architect. He also writes the Security Adviser blog.
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