A copycat of the feared CryptoLocker ransomware has recently emerged and already infected thousands of computers in the US and at least six European countries.
The Locker virus, which demands US$ 150 (£92) payment from victims to decrypt their files, was discovered by US-based security research firm IntelCrawler on 12 December. The company say it began large-scale distribution on 5 December. It has an estimated 40 to 50 variants, and just one of these bots has already infected close to 6,000 machines.
IntelCrawler CEO Andrey Komarov told SCMagazineUK.com that victims have so far been identified in three US states, plus Germany, Russia, The Netherlands, Turkey, Poland and Georgia. The numbers of infections are rising.
The malware targets computers using a variety of methods including spam and Trojan downloads. It avoids suspicion by checking the user has an internet connection via adobe.com, then makes encrypted copies of all the user's files before deleting the originals.
All the Locker variants demand a US$ 150 payment to decrypt the files via the Perfect Money payment service or a card transaction through the Russian QIWI Visa payments firm, giving users the details needed to pay the ransom by placing a CONTACT.TXT file in each of their directories.
Locker could be the forerunner of more Cryptolocker imitators – if users respond to the pressure to pay the ransom, according to cyber security expert Alex Fidgen, director at MWR InfoSecurity.
He told SCMagazineUK.com: "With the Locker malware, we're starting to see copycat ransomware spring up, mostly due to the presumed success of the CryptoLocker malware. We will only see more of this kind of malware if people pay the demands of the authors.”
Fidgen advised: “The best way people can avoid having to pay is to keep their software updated against all known vulnerabilities and to adhere to best security practices so they don't get the malware in the first place. They should also keep regular backups up-to-date so that if they do get attacked there's little damage done."
The Locker malware is based on the TurboPower LockBox library of tools and uses AES-CRT to encrypt the victim's files. IntelCrawler suspects the campaign might be the brainchild of well-known spammer ‘SEVERA'.
Komarov told SCMagazineUK.com that his firm has established how to decrypt infected machines. This makes the new variant less threatening than the CryptoLocker original which was first spotted in September and which researchers are still trying to crack.
Locker can also be detected by some anti-virus systems, but Komarov warned that this will not stop the criminals behind it. He told us: “We predict new obfuscated and encrypted builds that they will update and use in the near future.”