Attackers are using a new technique called ‘intermittent encryption’ to bypass detection, according to a new report by SentinelOne.
With intermittent encryption, attackers can better bypass systems that use statistical analysis to detect an ongoing ransomware infection.
Since statistical analysis is based on the intensity of the input and output operations of operating system files, the intermittent encryption technique reduces the intensity of the input/output operations of files. It also shows a greater similarity between unencrypted and encrypted versions of a particular file. This is possible because only a few bytes in the file are changed.
The threat groups that already use intermittent encryption include Qyick, PLAY, Agenda, Black Basta and BlackCat/AlPHV ransomware, according to the researchers.
To protect systems from ransomware attacks that bypass detection by intermittent encryption, the researchers advise companies to keep their operating systems and all software running on them up-to-date and patched to prevent them from being compromised by a common vulnerability.
In addition, organizations are advised to use security solutions to try to detect the threat before the ransomware is launched on one or more computers.
It is also important that organizations enable multi-factor authentication and create awareness for every user, especially with regard to emails.
The sources for this piece include an article in TechRepublic.