Industrial Malware Focuses on Linux

Monday, January 9, 2017 @ 04:01 PM gHale

KillDisk malware is now infecting Linux machines, researchers said.

The malware had been targeting industrial companies, said researchers at ESET.

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Previously, KillDisk was one of the tools used in BlackEnergy when it targeted the Ukraine’s energy sector in late 2015.

The malware can wipe entire hard drives and render systems inoperable, KillDisk just added encryption capabilities and can now act more like ransomware.

The malware is now associated with a threat group dubbed TeleBots, which is believed to be an evolution of the Russia-linked BlackEnergy (Sandworm) group, said ESET researchers Robert Lipovsky and Peter Kalnai in a blog post.

The group targeted Ukraine’s financial sector with various tools, including a newer version of KillDisk set to become active after a specific period of time and to overwrite files that featured specific extensions.

The file-encrypting variant of KillDisk, which was detailed last month, was targeting Windows systems, encrypted files, and demanded $250,000 for the decryption key. ESET said even if the victim pays the ransom, the chances are slim they would be able to recover the files.

Moreover, the researchers said KillDisk is now targeting Linux systems, including workstations and servers, which is likely to cause even more damage. The ransom message is similar with the one used in the Windows variant, and the same is true for the demanded ransom: it is still 222 Bitcoin, or around $250,000.

The Linux variant of the malware displays the ransom note in an unusual manner: Within the GRUB bootloader, researchers said. What this means is the malware overwrites the bootloader entries to display the ransom text.

The main encryption routine recursively traverses multiple folders within the root directory up to 17 subdirectories in depth, while files in them are encrypted using Triple-DES applied to 4096-byte file blocks. The threat uses a different set of 64-bit encryption keys for each of the encrypted files, researchers said.

“The group (or groups) of attackers behind these operations has had an interest in various platforms – whether it was Windows PCs controlling SCADA/ICS systems, or workstations in a media agency,” the researchers said in the blog post. “With this latest expansion, attackers can use KillDisk to destroy files on Linux systems. Nonetheless, any ties between orchestrators of these attacks remain unclear and purely circumstantial.”

ESET researchers went on to say, “if you’ve become a victim of ransomware, don’t pay up, since there’s no guarantee of getting your data back. The only safe way of dealing with ransomware is prevention – education, keeping systems updated and fully patched, using a reputable security solution, keeping backups and testing the ability to restore.”

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