Gootloader Abuses 1,000-Part ZIPs to Evade Detection
🛡️ Gootloader operators now deliver malformed ZIP archives that concatenate up to 1,000 parts to evade analysis and detection. The archived JScript unpacks successfully with Windows' built-in extractor while tools relying on 7-Zip and WinRAR often crash. Samples employ truncated EOCD entries, randomized disk fields, metadata mismatches and XOR-encoded blobs appended client-side. Researchers devised a YARA rule and advise changing the default .js opener to Notepad and blocking wscript.exe/cscript.exe where possible.
