Description

A new ransomware group named Interlock has emerged, targeting organizations globally with a focus on FreeBSD servers. Active since late September 2024, Interlock has claimed responsibility for attacks on at least six entities, including Wayne County, Michigan, which faced a cyber incident in early October. Following ransom demands, the group has leaked stolen data on their site. Initial insights were shared by incident responder Simo, who discovered a new backdoor linked to Interlock. Cybersecurity researcher MalwareHuntTeam identified a FreeBSD ELF encryptor. Attempts to execute the encryptor on a virtual machine were unsuccessful, although it was confirmed to be specifically compiled for FreeBSD. Unlike typical attacks targeting Linux systems, Interlock's focus on FreeBSD is noteworthy, particularly as it’s prevalent in critical infrastructure. Trend Micro reports that this approach allows attackers to disrupt essential services and demand significant ransoms. They have also noted the discovery of both FreeBSD and Windows encryptors associated with Interlock. The Windows variant effectively erases event logs and may self-delete through a DLL. During file encryption, affected files are marked with the .interlock extension, accompanied by a ransom note titled !README!.txt, detailing the situation and providing links to negotiation sites on Tor. Each victim receives a unique "Company ID" for communication. Interlock’s ransom demands range from several hundred thousand to millions of dollars, depending on the organization’s size. Organizations are urged to enhance their cybersecurity measures to mitigate the risk of such attacks.