A threat actor is promoting on underground criminal forums a vendor-independent UEFI rootkit that can disable security software and controls, cybersecurity veteran Scott Scheferman warns.

Dubbed ‘Black Lotus’, the Windows rootkit is a powerful, persistent tool being offered for sale at $5,000, with $200 payments per new version and featuring capabilities resembling those employed by state-sponsored threat actors.

Written in Assembly and C, Black Lotus is 80 kilobytes in size and features geofencing, to avoid infecting countries in the CIS region.

According to Scheferman, the threat packs evasion capabilities such as anti-virtualization, anti-debugging, and code obfuscation, and can disable security applications and defense mechanisms on target machines, including Hypervisor-protected Code Integrity (HVCI), BitLocker, and Windows Defender.

By loading code before the booting process completes, the rootkit can bypass user access control (UAC) and secure boot, it can load unsigned drivers, and can persist undetected in the UEFI firmware of the target device, supposedly indefinitely.

Black Lotus, Scheferman says, provides a full set of capabilities to attackers, including file transfer and tasking support, and can potentially become a major threat across IT and OT environments.

“Considering this tradecraft used to be relegated to APTs like the Russian GRU and APT 41 (China nexus), and considering prior criminal discoveries we’ve made (e.g. Trickbot’s #Trickboot module), this represents a bit of a ’leap’ forward, in terms of ease of use, scalability, accessibility and most importantly, the potential for much more impact in the forms of persistence, evasion and/or destruction,” Scheferman says.

According to Scheferman, Black Lotus supposedly being able to target a broad range of device types might suggest that its developers are targeting an undocumented bootloader vulnerability impacting many vendors.

Kaspersky too got wind of Black Lotus, pointing out that the rootkit’s advanced capabilities were previously typical of nation-state malware, but are now increasingly accessible to cybercriminals.

By Ionut Arghire on Mon, 17 Oct 2022 11:01:14 +0000
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