Thanatos Ransomware Is First to Use Bitcoin Cash. Messes Up Encryption

Ransomware developers continue to release infections that are clearly not tested well and contain bugs that may make it difficult, if not impossible, for victims to recover their files. Such is the case with the new in the wild ransomware called Thanatos that has been discovered by security researcher MalwareHunterTeam.

When the Thanatos Ransomware infects a victim it will use a new key for each encrypted file. The problem, according to researcher Francesco Muroni, is that these keys are never saved anywhere. This means that if a user pays the ransom, the ransomware developer does not have a method that will actually be able to decrypt each file. Therefore, it is not recommended that victims pay the Thanatos ransom for any reason.

The good news is that according to Muroni it may be possible to brute force the encryption key for each file. This would take quite a bit of time and would require the file to be a common file type with a known magic header.

While the encryption part of Thanatos is a mess, the ransomware does introduce something new. That is being the first ransomware to accept Bitcoin Cash as a ransom payment.

For those unfamiliar with Bitcoin Cash, it is a new cryptocurrency that was spun off from Bitcoin. When Bitcoin hit block 478,558, Bitcoin was forked into a new cryptocurrency called Bitcoin Cash. When this fork occurred, Bitcoin holders were then given an equivalent amount of Bitcoin Cash. For example, if a user had 2 Bitcoins at the time of the fork, they would have received 2 Bitcoin Cash as well.

While Thanatos accepts both Bitcoin and Etherum as a ransom payment, this is the first time that Bitcoin Cash has been accepted as shown in the ransom note below.

When the Thanatos Ransomware encrypts a computer it will generate a new encryption key for every file encrypted. As discussed already, unfortunately these encryption keys are not saved anywhere and thus according to researchers it would not be possible for the developers to decrypt the files even if a ransom payment is made.

When encrypting files it will append the .THANATOS extension to an encrypted file's name. For example, a file named test.jpg would be encrypted and renamed as test.jpg.THANATOS.

After the encryption process is finished it will then connect to iplogger.com/1t3i37 URL in order to keep track of the amount of victims that have been infected.

Finally, it will generate an autorun key called "Microsoft Update System Web-Helper" that opens the README.txt ransom note every time a user logs in. This ransom note can be seen in the article's previous section.

This ransom note contains instructions to send a $200 USD ransom payment to one of the listed Bitcoin, Ethereum, or Bitcoin Cash addresses. The user is then instructed to contact thanatos1.1@yandex.com with their unique victim ID in order to receive a decryption program.

As already stated, this ransomware can not be decrypted normally due to it not saving the encryption keys and thus the ransom payment should not be made. If anyone is infected with this ransomware, they should contact us about the possible creation of a brute force program.

In order to protect yourself from ransomware in general, it is important that you use good computing habits and security software. First and foremost, you should always have a reliable and tested backup of your data that can be restored in the case of an emergency, such as a ransomware attack.

You should also have security software that incorporates behavioral detections to combat ransomware and not just signature detections or heuristics.For example, Emsisoft Anti-Malware and Malwarebytes Anti-Malware both contain behavioral detection that can prevent many, if not most, ransomware infections from encrypting a computer.

Last, but not least, make sure you practice the following security habits, which in many cases are the most important steps of all:

For a complete guide on ransomware protection, you visit our How to Protect and Harden a Computer against Ransomware article.

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IOCs

fe1eafb8e31a84c14ad5638d5fd15ab18505efe4f1becaa36eb0c1d75cd1d5a9

---------------------------------------------------_____________ _____________________ /___/ / / /|/ | / /|/___/ __ \/ ___// / / /_/ / /| | /|/ / /| | / / / / / /\__ \/ / / __/ ___ |/ /|/ ___ |/ / / /_/ /___/ / /_/ /_/ /_/_/|_/_/ |_/_/|_/_/\____//____/--------------------------------------------------- Thanatos v1.1Your files was encrypted. To decrypt your files, follow next steps:1. Send $200 to one of these wallets:BTC: 1HvEZ1jZ7BWgBYPxqCvWtKja3a9hsNa9EhETH: 0x92420e4D96E5A2EbC617f1225E92cA82E24B03efBCH: qzuexhcqmkzcdazq6jjk69hkhgnme25c35s9tamz6f2. Send your TXID and your MachineID to mailE-Mail: thanatos1.1@yandex.comMactineID: 6bfd5faf-54f4-4620-a82d-4558a9132a25 ---------------------------------------------------Do not waste your time, files can only be decrypted by our decode tool.

thanatos1.1@yandex.com

README.txt

HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Run "Microsoft Update System Web-Helper" = "C:\Windows\System32\notepad.exe %UserProfile%\Desktop\README.txt"