Microsoft Decryptor ransomware is crypto-virus, that uses asymmetric RSA-4096 encryption algorithm to encrypt important files on users machine. It is basically updated version of CryptXXX and UltraCrypter ransomware. Virus demands a ransom of 1.2 BitCoins (~$646) to decrypt files and if ransom is not paid within 96 hours, the amount doubles to 2.4 BitCoins. Microsoft Decryptor does not modify encrypted files names and creates 3 files (README.txt, README.bmp, and README.html) in every affected folder. README.bmp is then used to change desktop background.
Stampado Ransomware is ransomware virus, that uses asymmetric AES-256 encryption to encrypt important files on users machine. Its particularity is that anyone can buy "license" for this ransomware and spread it using his or her own channels. Virus then demands a ransom from user to send secret key that will allow to decrypt infected files. Stampado "encourages" user to pay the ransom faster by giving 96 hours deadline. It also removes random files every 6 hours and that is called "Russian Roulette". This is done After this period private key will be deleted and encryption will be impossible.
WildFire Locker is virus, that uses asymmetric AES-256 encryption to lock important files and documents on victims machine. It asks ransom for file decryption. Ransom amount is about $/€299, however, if it is not paid within 7 days amount will increase to $/€299. Ransomware adds extension .wflx to every encrypted file and also creates file "HOW_TO_UNLOCK_FILES_README_(victim's ID).txt", that contains instructions to unlock those files.
Zepto is new file-encrypting virus, previously known as Locky ransomware. Virus uses AES-256 algorithm to encrypt your files. Zepto encrypts following file types: documents, images, game files, e-mails. Ransomware adds extension .zepto to every encrypted file and also creates file "_{random number}_HELP_instructions.html", and in this file hackers give instructions to pay the ransom and decrypt files. Threat also modifies name of the affected files with hexadecimal chars, making it difficult to understand where certain files are.
Crypt0l0cker (TorrentLocker) is file-encrypting virus and ransomware that targets following countries: Australia, Austria, Canada, Czech Republic, Italy, Ireland, France, Germany, Netherlands, Korea, Thailand, New Zealand, Spain, Turkey, and the United Kingdom. For some reason it is not affecting US-based PCs. The ransom amount is 2.2 Bitcoins, which is currently about $330 GBP. Crypt0l0cker encrypts all files except ones with following extensions: avi, wav, mp3, gif, ico, png, bmp, txt, html, inf, manifest, chm, ini, tmp, log, url, lnk, cmd, bat, scr, msi, sys, dll, exe. Because those files are needed for OS operation.