What Is a Decompression Bomb?

What is a File Decompression Bomb on a Computer?

Free antivirus software are nowadays available everywhere online. But did you know that not all scans on your system will keep you protected? A decompression bomb is a file that by design is meant to crash your antivirus and ultimately, system, by the use of compression technology. What then is this ‘compression technology’?

Compression and Binary

You have probably downloaded a ZIPped or RAR file at one point or another. Large files will often come compressed to not only make downloading easy, but also transfer and to save on storage. Imagine downloading a whole television show with over twelve episodes, or a high-graphics game. They would both definitely need large storage.

To make them more or easily manageable, such files are compressed. Compression technology rewrites a file’s binary code fragments, so that it is smaller. Let’s briefly talk about binary codes and their relevance to decompression.

Your system’s files are stored in a series of code, represented by 1s and 0s. This is referred to as binary code. The larger a file is, the longer its code could be. A code fragment could have sets of repeated numbers, which in basic compression algorithm, will be rewritten to become smaller.

The problem with reducing the size of binary fragments is that it can make an overly huge file seem small, while in the real essence, it is just minimized. This is risky with viruses. Should you scan such an infected file, your antivirus will potentially  crash.


Antiviruses scan all files, including those downloaded. It will also decompress or open the zipped. If the files are too large upon unzipping, they can overload your antivirus or system. A virus could be hidden within those trillions of minimized data, which may eventually harm your system.

As the name suggests, such a virus hides within a compressed file. It is unlocked or released into your system upon decompressing it. A virus hidden within myriads of files may not be easily traced, if at all it can be found.

While you may be weary, therefore, of the files you unzip, your antivirus may proceed with scanning it before you’re sure about its safety. The chances that such software will involuntary miss the virus, are almost absolute.

A decompression bomb’s structure

A decompression bomb generally generates a long-pattern code. The code is grouped into simplified, smaller fragments. Its ZIP or RAR files may, therefore, have but a small size. The instructions within, nonetheless could potentially produce large files.

As aforementioned, whatever mischief such large files may contain will often go undetected. The world’s largest and most powerful decompression bomb is sized at a meagre 5KB, with the capability of producing a 4ZB file.

Besides a disappointing antivirus, your computer is at risk if the zipped file in question is capable of producing a file larger than your disk space. This could cause your system to crash ultimately.

How to identify a decompression bomb

You could be wondering if there’s a way to go around this hostile file in your computer without causing a system crash, or any adverse effects that could put you at a disadvantage or loss. Care is one of the obvious things that you should always watch.

Take your time to find a credible antivirus if you don’t have one. While it could be tempting to try out free software, if it’s not something you can entirely trust your PC to, then you shouldn’t risk it. A good antivirus, on the other hand, isn’t labelled or tagged.

Before using an antivirus that you’re new to, it could be a good idea to check out what other people are saying about it. Read reviews and feedback by confirmed users, and you could get a step closer to securing your PC.

No antivirus can ever be perfect; they will always try to eliminate all threats possible, but if the threat is new and contained in a file too large for it to handle within the short time it has, then your system could fall at a risk. Therefore, watch sites where you download your files.

Some sites may contain malware or have files that are corrupted. Downloading these files into your computer is in other words, transferring potential viruses from the sites into your system. Would you want to be doing that? To avoid any risks, download only from trusted sites.

I hope you found this article helpful, and learned something useful about decompression bombs. Keep your computer safe and stay safe!

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