The most infamous example, 42.zip , is a 42-kilobyte file that, when fully extracted, expands to 4.5 petabytes (
Here is a deep report on its mechanics, purpose, and mitigation: 1. What is it?
The file is built by compressing a set of files that are themselves compressed, repeating this process -levels deep. Infinite.zip
A tiny compressed file (often only a few kilobytes or megabytes in size) that expands into a gargantuan amount of data (petabytes, exabytes, or "infinite" space) upon extraction.
Modern antivirus software and archiving tools (like 7-Zip) often limit the number of nested levels they will scan or extract to avoid this type of attack. The most infamous example, 42
It relies on recursive compression —layers upon layers of nested ZIP files. A single file might contain 100 zip files, each containing 100 more, and so on. 2. How it Works (The Mechanics)
It is used to overwhelm security software that attempts to scan within archives, preventing it from detecting other, actual malicious files. 4. Mitigation and Defense A tiny compressed file (often only a few
Do not extract unknown or unexpectedly small zip files from untrusted sources. zip and recursive zip bombs ? 42.zip (2004) - Hacker News