More than 500 hosts have been newly compromised en masse by the ESXiArgs ransomware strain, most of which are located in France, Germany, the Netherlands, the U.K., and Ukraine.
The findings come from attack surface management firm Censys, which discovered “two hosts with strikingly similar ransom notes dating back to mid-October 2022, just after ESXi versions 6.5 and 6.7 reached end of life.”
The first set of infections dates back to October 12, 2022, much earlier than when the campaign began to gain traction at the start of February 2023. Then on January 31, 2023, the ransom notes on the two hosts are said to have been updated with a revised version that matches the ones used in the current wave.
Some of the crucial differences between the two ransom notes include the use of an onion URL instead of a Tox chat ID, a Proton Mail address at the bottom of the note, and a lower ransom demand (1.05 Bitcoin vs. 2.09 Bitcoin).
“Each variant of the ransom notes from October 2022 through February 2023 are strikingly similar in wording to the note of an earlier ransomware variant, Cheerscrypt, which gained notoriety in early 2022,” researchers Mark Ellzey and Emily Austin said.
It’s worth noting that ESXiArgs is suspected to be based on the leaked Babuk ransomware code, which also spawned other variants such as Cheerscrypt and PrideLocker last year.