The Russian incursion into Ukraine is prompting warnings from the DHS and security researchers about the potential for Russian cyberattacks on U.S. companies.
Researchers have been tracking the malware packer since 2020 in dozens of campaigns that have impacted hundreds of victims.
The known tactic, which helps attackers sidestep detection, has been observed in spam messages that deploy Emotet.
Researchers believe that China-linked threat group APT41 is behind the highly targeted attack.
The U.S. government gave details on 17 MuddyWater samples and linked the threat group to the Iranian intelligence service.