Security Experts:

New Modem Wiper Malware May be Connected to Viasat Hack

A pair of security researchers at SentinelLabs have intercepted a piece of destructive wiper malware hitting routers and modems and found digital breadcrumbs suggesting a link to the devastating Viasat hack that took down wind turbines in Germany.

SentinelLabs malware hunters Juan Andres Guerrero-Saade and Max van Amerongen believe the newest wiper -- called AcidRain -- is part of a larger supply chain attack aimed at crippling Viasat’s satellite internet service.

In an official statement, Viasat confirmed a dual-pronged attack against its KA-SAT network ended with malicious software commands rendering tens of thousands of modems across Europe inoperable by overwriting key data in their internal memory. 

The Viasat attack, coming just as Russia was launching its invasion of Ukraine, also impacted modem service in France and Italy and even paralyzed wind turbines in Germany, according to published reports.

[ READ: Ukraine Cyberattack: Data-Wiper With Ransomware Smokescreen ]

Now, SentinelLab’s threat hunters are sharing notes on the discovery of the newest wiper and documenting code overlaps and other evidence linking the malware to the satellite network takedown.

"[We believe] the threat actor used the KA-SAT management mechanism in a supply-chain attack to push a wiper designed for modems and routers," Guerrero-Saade and Van Amerongen wrote. "A wiper for this kind of device would overwrite key data in the modem’s flash memory, rendering it inoperable and in need of reflashing or replacing."

The researchers described Viacom's public statement as “incomplete” and said its own technical analysis found similarities with the ongoing VPNFilter malware attacks attributed by the U.S. FBI to a known Russian government APT group.

"We assess with medium-confidence that there are developmental similarities between AcidRain and a VPNFilter stage 3 destructive plugin. In 2018, the FBI and Department of Justice attributed the VPNFilter campaign to the Russian government," the researchers said.

[ READ: Satellite Modems Nexus of Worst Cyberattack of Ukraine War ]

Noting that AcidRain is the 7th wiper malware associated with the Russian invasion of Ukraine, the SentinelLabs team said the suspicious file was uploaded to the VirusTotal multi-scanner service from Italy with the name ‘ukrop’  and was designed to be destructive.

“AcidRain’s functionality is relatively straightforward and takes a bruteforce attempt that possibly signifies that the attackers were either unfamiliar with the particulars of the target firmware or wanted the tool to remain generic and reusable,” the report said.

“The binary performs an in-depth wipe of the filesystem and various known storage device files. If the code is running as root, AcidRain performs an initial recursive overwrite and delete of non-standard files in the filesystem.” it added.

Related: U.S. Gov Warning: Firmware Security a 'Single Point of Failure'

Related: SATCOM Cybersecurity Alert Issued as Authorities Probe Possible Russian Attack

Related: Ukraine Cyberattack: Worm-Spreading Data-Wiper With Ransomware Smokescreen

Related: Microsoft Says Cyberattacks in Ukraine Hitting Civilian Digital Targets

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Ryan Naraine is Editor-at-Large at SecurityWeek and host of the popular Security Conversations podcast series. Ryan is a veteran cybersecurity strategist who has built security engagement programs at major global brands, including Intel Corp., Bishop Fox and Kaspersky GReAT. He is a co-founder of Threatpost and the global SAS conference series. Ryan's past career as a security journalist included bylines at major technology publications including Ziff Davis eWEEK, CBS Interactive's ZDNet, PCMag and PC World. Ryan is a director of the Security Tinkerers non-profit, an advisor to early-stage entrepreneurs, and a regular speaker at security conferences around the world. Follow Ryan on Twitter @ryanaraine.