Unlike most malware, ransomware is not stealthy. It's loud and obnoxious, and if you've been infected, the attackers will tell you so in no uncertain terms. After all, they want to be paid.
“Your personal files are encrypted,” the message on the computer blares. “Your documents photos, databases, and other important files have been encrypted with strongest encryption and unique key, generated for this computer.” While the language may vary, the gist is the same: If you don’t pay the ransom -- typically within 48 to 72 hours -- your files are hosed.
Or are they? There is a slim possibility the perpetrators may be trying to fake you out and the files haven’t been encrypted. While not a common scenario, it does happen, according to industry experts. Rather than paying up, you can bypass the scary fake message and move on with your day.
“There are a number of examples where true encryption doesn’t occur. Instead, cyber criminals rely on the social engineering edge of the attack to convince people to pay,” warns Grayson Milbourne, director of security intelligence at Webroot.
Is it real or fake?
It takes only a few seconds to confirm whether it’s a real infection or a social engineering scam.
If the ransom demand includes the name of the ransomware, then there’s no mystery, and you're in trouble. Ransomware families that identify themselves include Linux.Encoder -- the first Linux-based ransomware -- which clearly says “Encrypted by Linux.Encoder.” CoinVault identifies itself by listing the support email address. TeslaCrypt and CTB-Locker are also among the well-known ransomware families that tell you who is holding your files hostage.
But there are plenty of ransom plays that don’t bother with names. For example, CryptoLocker simply warned that your files have been encrypted and never flaunted its name. Instead, you'll have to look for other clues: Is there a support email address? Search the Internet for the bitcoin payment address or the actual ransom message and see what comes up on forums or from security researchers.
If you can't identify the ransomware, then there's a chance it could be fake. In such cases, your files aren't actually encrypted; the attacker simply pops up a scary message and locks the screen. The ransom demand typically shows up inside a browser window and doesn’t let the user navigate away, or it locks the screen and displays a dialog box asking for an encryption key. Because the victim can’t close the message, it looks real.
If it’s possible to close out of the screen using key commands, such as Alt-F4 on Windows and Command-W on Mac OS X, then the ransom demand is fake. Or try force-restarting the device and see if the message goes away.
Ransomware tends to change the filename as part of the encryption process. Locky adds a .lock file extension to all documents, while CryptXXX uses the .crypt file extension. Look through the files and see which files have been modified. See if you can still open them or if you can change the file extensions back and open the files. Sometimes, the file extensions have been changed without actually encrypting the files.
Get back into the system using a Linux Live CD and search the system to see if the actual files have been moved or renamed. Most modern operating systems can search the contents of the file along with filenames.
Don’t get your hopes too high
While it’s good to be skeptical, if you see a ransom demand, it's probably legitimate. Thanks to crimeware kits preloaded with ransomware and ransomware as a service, the barrier to entry is much lower. Script kiddies and other less technically inclined criminals are trying to piggyback on the success of real ransomware gangs without putting in the work.
“The simplicity of buying your crypto-malware from a crime-as-a-service provider now means cyber criminals can easily deploy a ransomware attack that uses complex and effective encryption against their targets,” says Mimecast’s cyber security strategist, Orlando Scott-Cowley.
Ransomware infections are a serious threat and fake attacks are relatively rare. But before you start the process of rebuilding your machine to recover from a ransomware infection, make sure you aren’t being scammed. It takes only a few minutes.
If it turns out you've been victimized by the real thing, you may have another slim chance: publicly available decryption tools.