Never-before-seen data wiper may have been used by Russia against Ukraine

Researchers have unearthed never-before-seen wiper malware tied to the Kremlin and an operation two years ago that took out more than 10,000 satellite modems located mainly in Ukraine on the eve of Russia’s invasion of its neighboring country.

AcidPour, as researchers from security firm Sentinel One have named the new malware, has stark similarities to AcidRain, a wiper discovered in March 2022 that Viasat has confirmed was used in the attack on its modems earlier that month. Wipers are malicious applications designed to destroy stored data or render devices inoperable. Viasat said AcidRain was installed on more than 10,000 Eutelsat KA-SAT modems used by the broadband provider seven days prior to the March 2022 discovery of the wiper. AcidRain was installed on the devices after attackers gained access to the company’s private network.

Sentinel One, which also discovered AcidRain, said at the time that the earlier wiper had enough technical overlaps with malware the US government attributed to the Russian government in 2018 to make it likely that AcidRain and the 2018 malware, known as VPNFilter, were closely linked to the same team of developers. In turn, Sentinel One’s report Thursday noting the similarities between AcidRain and AcidPour provides evidence that AcidPour was also created by developers working on behalf of the Kremlin.

Technical similarities include:

• Use of the same reboot mechanism
• The exact logic of recursive directory wiping
• The same IOCTL-based wiping mechanism.

AcidPour also shares programming similarities with another piece of malware attributed to Sandworm: CaddyWiper, which was used against various targets in Ukraine.

“AcidPour is programmed in C without relying on statically compiled libraries or imports,” Thursday’s report noted. “Most functionality is implemented via direct syscalls, many called through the use of inline assembly and opcodes.” Developers of CaddyWiper used the same approach.

Bolstering the theory that AcidPour was created by the same Russian threat group behind previous attacks on Ukraine, a representative with Ukraine’s State Service of Special Communications and Information Protection told Cyberscoop that AcidPour was linked to UAC-0165, a splinter group associated with Sandworm (a much larger threat group run by Russia’s military intelligence unit, GRU). Representatives with the State Service of Special Communications and Information Protection of Ukraine didn’t immediately answer an email seeking comment for this post.