RIPlace – A new Evasion Technique Let Ransomware to Encrypt Files Undetected

RIPlace a new evasion technique that allows threat actors to encrypt files on Windows-based computers without being detected by anti-ransomware products.

Nyotron’s Security researchers discovered a new technique that leverages Microsoft Windows file system rename operations to stay undetected from security products,

RIPlace Evasion Technique

Attackers can use this RIPlace method to alter any files on the computers running with Windows XP or the new version of operating systems.

According to Nyotron’s Research, all antivirus products including Endpoint Detection and Response tested so far were completely blind to file operations using this technique, including encryption.

Whenever a renamed file requests operation being called the IRP_MJ_SET_INFORMATION it requests to set metadata about a file with FileInformationClass set to FileRenameInformation and then filter gets a callback, so that it could filter the request.

Researchers call DefineDosDevice that can pass the “arbitrary name as the device name, and the original file path, as the target to point on.”

The RIPlace technique is that the callback function fails to parse the destination path using the common routine FltGetDestinationFileNameInformation and throw an error when passing the DosDevice path, but even though the rename operation gets succeeded.

Researchers said that with this technique, it is possible for a Ransomware strain to encrypt files and to bypass antivirus/anti-ransomware products.

Ransomware is still a serious threat it encrypts victim’s files and the attackers demand ransom to restore the files.

To maintain anonymity attackers employ the “Tor” service to communicate with the victim for hiding the IP. Ransomware being around the world since 1989, and it costs billions of dollars damage every year.

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