Category:	Malware
Type:	Trojan
Platform:	W32

Trojan:W32/Ransomcrypt is ransomware that encrypts files on the affected computer and demands payment, supposedly to provide a password decrypting the affected files.

Disinfection

F-Secure Anti-Virus is able to disinfect the ransom-trojan from the affected machine.

For more general information on disinfection, please see Removal Instructions.

Decryption of files

Investigations to determine if Trojan:W32/Ransomcrypt's encryption of personal files can be cracked are ongoing.

Trojan:W32/Ransomcrypt is ransomware that encrypts files on the affected computer, alledgedly because the user is "using unlicensed programms!", according to a text file note left by the malware author:

When first run on the system, Trojan:W32/Ransomcrypt will drop a randomly-named copy of itself in the %temp% folder; it will also iterate all folders on the system. Every document, image and shortcut file it finds will be encrypted and appended with the extension, .EnCiPhErEd:

In each folder, the trojan will also drop a file named "HOW TO DECRYPT.TXT" (see Image 1) that contains instructions on how to proceed with payment to remove the encryption.

Ransomcrypt will then create registry entries to associate the .EnCiPhErEd extension with itself so that the copy in %temp% will be launched whenever the encrypted files are run and demand the password to decrypt the files:

After 5 tries it will no longer accept passwords. And it then deletes itself, leaving the files encrypted.