Compression technology has simplified the process of downloading files. It’s able to shrink the size of files so that they become smaller and, thus, faster to download. Depending on the particular type of compression technology used, it may reduce the size of files by up to 90%.

If you regularly download and use compressed files, though, you should beware of zip bombs. A zip bomb is a cyber threat that leverages an oversized compressed file. Turning a blind eye to a zip bomb could crash your computer or worse.

What Is a Zip Bomb?

Also known as a decompression bomb, a zip bomb is a compressed file that’s designed to overload the victim’s computer with an excessive amount of data.

Whether compressed or uncompressed, all files contain data. Compressed files, however, typically contain less data than their uncompressed counterparts. You can run a compressed file through a compression/decompression program, which will essentially unpack it. A zip bomb is a type of malicious compressed file that, when decompressed, creates so much data that it causes crashes or other technical errors.

How Zip Bombs Work

There are different types of zip bombs, some of which work in different ways. With that said, nearly all zip bombs work by overloading the victim’s computer with an excessive amount of data.

You can’t determine the “true” size of a compressed file until you unpack it. Compressed files become bigger when decompressed. Zip bombs are designed specifically to decompress into a large size with an excessive amount of data.

There’s a zip bomb known as, for example. In its original and uncompressed format, it consists of just 42 KB of data. Decompressing the zip bomb, however, will result in over 4 PB of data. Even top-of-the-line storage drives can’t accommodate 4 PB of data.

Tips to Protect Against Zip Bombs

You can protect against zip bombs by running antivirus software. Zip bombs aren’t classified as computer viruses. Nonetheless, they are still a form of malware — and antivirus software can detect malware such as zip bombs.

Only downloading compressed files from trusted sources will lower your risk of sustaining a zip bomb attack. If you receive an email with a compressed file from an unknown sender, for example, you may want to avoid downloading it. It only takes a single zip bomb to crash your computer or even render it unusable. By downloading compressed files from trusted sources, you’ll be better protected against zip bombs and other cyber threats.