Kaspersky Lab analysts have traced the source of Krotten (see yesterday's blog by Yury Mashevsky for more information).
The program was spreading disguised as a program which would generate codes to top up mobile phones. It was placed on a site located in Russia which was hosted free of charge. The site (see screenshot left) states that the code generator was developed by Ukrainian hackers, mentions that the program will work for 'nearly all Ukrainian mobile service providers' and guarantees a 100% result.
Sites like this are often used by malware authors, as the users are not required to provide personal details and therefore enjoy total anonymity. If the site had been hosted in return for payment, it would have been far easier to track it down.
The result of the user attempting to top up his mobile account resulted in the Trojan author's account being topped up.
We sent information about the site to the hosting company's support department, and within ten minutes, the site had been closed down.
Even though the original site has been closed, the Trojan program may well pop up on another site which is hosted free of charge. So this is a good time to remind users of just how smart these social engineering techniques are, and how virus writers and hackers are cashing in on users' gullibility.
We're starting to see a growth in the number of malicious programs which are being used to get money out of users - a type of cyber extortion.
Examples of this type of malicious program are Virus.Win32.GPCode, and Trojan.Win32.Krotten. Today we detected the latest modification of Krotten, Trojan.Win32.Krotten.n.
Trojan.Win32.Krotten uses exactly the same approach as GPCode. It corrupts data on the victim machine, and also displays a message saying that the data will be unencrypted once payment is received by the user/ author of the malicious program. Krotten differs from GPCode in that GPCode encrypted data saved to disk. Krotten corrupts the system registry. The author of Krotten offers to restore the corrupted data in return for a sum equivalent to approximately $5.
The Russian text states that within 12 hours following receipt of payment (to be sent to an email address given in the message) the user will receive a file which will delete the malicious program. The message, which mentions an account in Kiev, and specifies an amount in hryvnia, points to the Ukrainian origin of Krotten.
Detection for Trojan.Win32.Krotten.n has of course been added to our antivirus databases. You can also restore your registry settings using our free utility.
Once again, this is yet another case which shows that you should never open an unexpected attachment. And users should never send money to virus writers or those who are using them in cyber scams. This just encourages them to create a new version of whatever virus they are using, and launch another attack.