The attack, dubbed ShadowHammer, affected many thousands of computers, but it was a highly targeted attack. Kaspersky became aware of the scheme in January when it updated its scanning tools with supply-chain detection technology. A supply-chain attack involves bundling malware with systems when they are manufactured, sold, or via vendor update systems. ShadowHammer went undetected for so long because it didn’t have any immediate effect on most of the infected systems. The attackers were looking for about 600 very specific machines.
Kaspersky believes those behind ShadowHammer also perpetrated the CCleaner attack 2017. That malware campaign also targeted Asus and could be how the attackers gained access to the Asus servers. Kaspersky will publish a full report on the malware soon, but there’s a summary post already available. Researchers have also put up a page where you can input your MAC address to see if it was on the target list. Kaspersky’s security tools will now detect and remove ShadowHammer as well.