Anatova ransomware is a new cryptoransomware variant that appears to have been released on January 1, 2019. It is stealthy, can infect network shares, has already been used in attacks in many countries around the world. It could well prove to become a major ransomware threat in 2019.
Ransomware has somewhat fallen out of favor with cybercriminals as cryptocurrency mining malware offers greater potential for profit. The development of new ransomware variants has slowed, but new variants are still emerging and the threat from ransomware is not going away any time soon. Ransomware attacks are still profitable for cybercriminals and as long as that remains the case the attacks will continue.
Anatova ransomware was identified and named by security researchers at McAfee. The name was taken from the name on the ransomware note. The previously unknown ransomware variant has been used in at least 10 countries, with over 100 Anatova ransomware attacks identified in the United States, more than 65 in Belgium, and over 40 in France and Germany.
Not only does the ransomware variant employ a range of techniques to avoid detection, infection can cause major damage and widespread file encryption. Further, the modular design allows the developers to easily add new functionality in the future.
Most of the strings in Anatova ransomware have been encrypted and different keys are required to decrypt them. Those keys have been embedded in the executable. 90% of calls are dynamic and use non-suspicious Windows APIs and standard C-programming language.
Once downloaded and executed, the ransomware performs a check of the name of the logged in user against a list of encrypted names and will exit if there is a match. Names that prompt an exit include tester, lab, malware, and analyst. These names are commonly used on virtual machines and sandboxes. A check will also be performed to determine the country in which the device is located. The ransomware will exit if the device is in any CIS country, Egypt, Syria, Morocco, Iraq, or India.
Anatova ransomware scans for files smaller than 1MB and checks for network shares, although care is taken not to disrupt the operating system during this process and raise a flag before files are encrypted. Once files have been identified, the encryption routine starts. The ransomware uses its own key, so each victim requires a separate key to unlock the encryption.
Once the encryption process has run, the ransom note is dropped on the desktop, the memory is cleaned, and volume shadow copies are overwritten 10 times to ensure files cannot be recovered from local backup files.
The ransom demand is relatively high – Around $700 (10 DASH) per infected machine. Since multiple devices can be infected with a single installation, the total ransom demand could well be considerable.
What is not 100% certain is how the ransomware is being distributed. McAfee detected one sample on a P2P file sharing network which masquerades as a free software program complete with game/application icon to encourage users to download and run the installer. Other attack vectors may also be used. Based on the current distribution vector, a web filter will offer protection against attacks if P2P file sharing/torrents sites are blocked.
The researchers believe Anatova ransomware has been created by highly skilled malware authors who are currently distributing a prototype of the ransomware. More widespread attacks are to be expected once this testing phase has been completed.