A method used to disable anti-malware software. See 42.zip
A zipbomb is a file archive made to temporarily disable your anti-malware software. Most of the time they are used to create an opening for more traditional malware.
They have a high compression ratio (for example having a small zip size and then when they're unzipped their size grows exponentially)
Rather than attacking the anti-malware outright, it distracts the software while being scanned because of its size. Scanning the file archives can take up huge amounts of system resources, often ending up in the PC running out of RAM.
They are usually small files to avoid detection, but when unpacked they overload the system. This technique was used on dial-up bulletin boards in the past.