Operation HollowQuill: Russian R&D Networks Targeted via Decoy PDFs

Description

Operation HollowQuill targets Russian research and defense networks, particularly the Baltic State Technical University, using weaponized decoy documents disguised as research invitations. The attack chain involves a malicious RAR file containing a .NET dropper, which deploys a Golang-based shellcode loader and a legitimate OneDrive application. The final payload is a Cobalt Strike beacon. The campaign focuses on academic institutions, military and defense industries, aerospace and missile technology, and government-oriented research entities within the Russian Federation. The threat actor employs sophisticated techniques, including anti-analysis measures, APC injection, and infrastructure rotation across multiple ASNs.