Today, MalwareHunterTeam discovered a new variant of the CryptoMix ransomware that appends the .TEST extension to encrypted files and changes the contact emails used by the ransomware. 

In this article I will provide a brief summary of any changes that have occurred in this new variant.  As we are always looking for weaknesses, if you are a victim of this variant and decide to pay the ransom, please send us the decryptor so we can take a look at it. You can also discuss or receive support for Cryptomix ransomware infections in our dedicated Cryptomix Help & Support Topic.

Changes in the TEST Cryptomix Ransomware Variant

While the encryption methods stay the same in this variant, there have been some slight differences. The ransom note is still named _HELP_INSTRUCTION.TXT, but now uses the [email protected], [email protected], [email protected], [email protected], and [email protected] emails for a victim to contact for payment information.

TEST CryptoMix Ransom Note

The next noticeable change is the extension appended to encrypted files. With this version, when a file is encrypted by the ransomware, it will modify the filename and then append the .TEST extension to encrypted file’s name. For example, a test file encrypted by this variant has an encrypted file name of 0D0A516824060636C21EC8BC280FEA12.TEST.

Folder of Encrypted TEST Files
Folder of Encrypted TEST Files

This variant also contains 11 public RSA-1024 encryption keys that will be used to to encrypt the AES key used to encrypt a victim’s files. This allows the ransomware to work completely offline with no network communication. This variant’s 11…

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