Mandiant researchers reported that the UNC2565 group behind the GOOTLOADER malware (aka Gootkit) continues to improve their code by adding new components and implementing new obfuscation techniques.
Gootkit runs on an access-a-as-a-service model, it is used by different groups to drop additional malicious payloads on the compromised systems. Gootkit has been known to use fileless techniques to deliver threats such as the SunCrypt, and REvil (Sodinokibi) ransomware, Kronos trojans, and Cobalt Strike.
In the past, Gootkit distributed malware masquerading as freeware installers and it used legal documents to trick users into downloading these files.
The attack chain starts with a user searching for specific information in a search engine. Attackers use black SEO technique to display a website compromised by Gootkit operators among the results.
Upon visiting the website, the victim will notice that it is presented as an online forum directly answering his query. This forum hosted a ZIP archive that contains the malicious .js file, which is used to establish persistence and drop a Cobalt Strike binary in the memory of the infected system.
