A new and potentially dangerous ransomware sample has been spotted infecting computers in the United States and at least nine other countries so far.
McAfee, the first to discover the emerging menace, has dubbed it Anatova, based on a name in the ransom note the malware leaves behind on infected systems.
In an advisory Tuesday, the security vendor described Anatova as having the potential to become a serious threat based on its obfuscation capabilities and ability to infect network shares. The malware also has a modular design, which allows attackers to add new malicious functions to it in the future.
Researchers from McAfee first discovered Anatova on a private peer-to-peer network, but they are still unsure of all the other ways the malware is being distributed. The malicious software typically has been using the icon of a game or application to trick users into downloading it on their systems.
Once executed, Anatova takes a variety of actions to avoid detection and ensure it can find and encrypt as many files as possible on an infected system. The malware then leaves behind a note demanding the equivalent of $700 in ransom for the key to decrypt the data.
"Anatova makes a few checks to make sure it is not run in a sandbox and the victim is not from certain countries," says Christiaan Beek, lead scientist at McAfee. Users from former Soviet bloc nations and some other countries, including Syria, Iraq, and India, are currently not under threat from the new ransomware strain.
Once it has gone past the initial checks, the malware looks for files that are smaller than 1 MB but makes sure not to disrupt the operating system while doing so. It also checks for network shares and will try to encrypt files in those locations. "One infection can disrupt a large part of an enterprise," Beek warns.
Significantly, each Anatova sample has its own key, meaning there's no master key available that could decrypt all files for all victims. Each victim would need a specific, separate key in order to unlock encrypted files, he explains.
After encrypting, the ransom note is written to the system. "It will then clean the memory so no keys can be dumped and [then] overwrites the backup files — volume shadow copies – 10 times to make sure that no backup of local files is possible," Beek notes. Anatova's modular design gives malware authors a way to add capabilities that would allow the malware to be distributed over the network or change its behavior while running.
Anatova is another sign that the ransomare threat is far from over, though there appears to be some uncertainty over whether the number of attacks are growing or declining. Kaspersky Lab, for instance, in December estimated that attacks involving crypto-ransomware had increased 43% in 2018 compared with the year before. But others have noted a decrease in ransomware attacks matched by a corresponding increase in attacks involving banking Trojans and cryptomining tools.
Regardless of the way the attacks are trending, most security researchers concur that ransomware continues to present a major threat for organizations. Last year numerous organization suffered major disruptions and financial losses from ransomware attacks, including The City of Atlanta, Port of San Diego, electronic health record provider Allscripts, and Hancock Health.
"Ransomware is a still a threat we have to take seriously," Beek says. "Be prepared, and do not pay. Paying will keep this business model alive."
According to McAfee, the developers and actors behind Anatova appear to be skilled malware authors. Though researchers at the company have a few theories on who is behind the new threat, it's still too early to jump to conclusions, Beek says. "We believe this was a prototype being tested and has a potential to become a serious threat," he says.
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