ATF Declares "Major Incident" After Cyberattack on System Holding Investigation Targets

The ATF classified a cyberattack on a standalone system containing "targets of ATF investigations" as a "major incident," a federal designation triggering mandatory congressional notification within seven days. The affected system is isolated from the bureau's broader network. The ATF has not confirmed whether data was stolen. The Qilin ransomware gang claimed responsibility without providing evidence.