When a user opened Lab02.7z and double-clicked what looked like a Word document, they unknowingly bypassed all of Windows' built-in security warnings. A hidden would launch in the background.

Today, Lab02.7z remains a textbook example of how attackers use mundane-looking archive files to weaponize small software bugs into major international security incidents.

The "story" of this file is actually the story of a clever vulnerability discovered in the popular archiver.

In late 2024, amidst the ongoing conflict, Ukrainian government and civilian organizations began receiving highly targeted . These emails appeared to be urgent documents, but tucked inside was a double-archived file: Lab02.7z . The Weapon: CVE-2025-0411

: To make the bait even more convincing, they used homoglyphs —characters from the Cyrillic alphabet that look identical to Latin letters—to make the malicious file inside look like a harmless .doc document. The Climax: SmokeLoader Deployment

: Hackers discovered that if they buried a malicious file inside a nested archive (like a ZIP inside Lab02.7z ), 7-Zip would fail to pass that "unsafe" flag to the inner file when extracted.