Do not unzip this – it is a huge 42 KB file !!

This is truly a work of  clever technical intelligence , You have a 42 KB zip file that expands to 45 PB ( Peta bytes 1012 bytes) . here is what the web site hosting this file says ,

The file contains 16 zipped files, which again contains 16 zipped files, which again contains 16 zipped files, which again contains 16 zipped, which again contains 16 zipped files, which contain 1 file, with the size of 4.3GB.

Now , how on earth does that can happen, well the answer is a characteristic property of zip compression , data redundancy , actually this file has a 4.2 GB file consisting of all zeroes , this means high redundancy and so zip is able to compress it that small .

now , go ahead and unzip it !!

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Computer Science Engineer by Education & a Programmer, Entrepreneur , Photographer by hobby & Passion who spends most of his time with his Computer/Mobile or his Camera - a Rebel t2i .
28 total comments on this postSubmit yours
  1. Wow !! that’s amazing .. actually i have studied about this in my Data Compression class ..

  2. Ohh my, thats FRIGGEN AWESOME! lol Thanks!

  3. Do not download.

    It contains a trojan.

  4. There was a small virus like program at my old high school and it was called getting “chickened” there was an infinite loop to write a folder “chicken” with a txt file that said chicken in it. it did this until your home folder was filled so id assume compressing crazy amounts of files in a small zip file is possible

  5. Yes, it is a trojan, of sorts. It’s a ‘archivebomb’ trojan. The only dangerous thing about it would be if you tried to unzip it in its entirety, because it’s so big.

  6. It’s not a trojan, it’s a zip bomb. They’re meant to disable AV programs by requiring an immense amount of resources to extract (and thus, scan). Attempting to extract 45 PB would render an antivirus process useless. Since most modern AV software checks for this, it will flag it as a trojan (or other type of malware).

  7. It’s not a trojan. Some virus softwares call it “Archbomb”, aka archive bomb.. because it’s doing exact what it says it’s doing. A 42kb file that expands to petabytes.. That’s normal behavior. Will it fill up your hard drive? yes.. will it tank your virus software in some cases if it tries to scan embedded archives.. yes. Do most virus scans catch it now? yes.. is it malicious or harmful? no.

  8. Yet another Zip Bomb…

    “One example of a Zip bomb was the file “” which was 42 kilobytes of compressed data, containing five layers of nested zip files for a total of 4.5 petabytes of uncompressed data.”

  9. I downloaded it, it looks legit to me…but then again, maybe I’ve already been infected and not know it. So I hope the trojan’s made for Windows only. I’m in Linux =]

    It can be done, but a dataset with that type of redundancy doesn’t happen often. In fact, if you zip two different zip files with different content, sometimes it’ll be larger than the two combined.

  10. McAfee Site Advisor also pegs this as malware; proceed with caution.

  11. Sorry, your anti-virus sucks.

    Neat, now time to go win some bets.

  12. Well , i figured it out , it’s called a zip bomb , It is not a Trojan , but as it will take ages to unzip and will occupy all your HD space , so that is why some people used it for DOS( Denial of service attacks ) and this technique got a bad name as it was used by Hackers to deface and dstroy important systems .
    Your antivirus will warn you , as it thinks of it as a trojan .. as it willl try to unzip the file to scan it , and if your AV is not good it will go on scanning and scanning … so take your chances

  13. @Tts2113 – Your name sounds crazy , anyways you are correct , it is possible to compress in this manner, hackers have been using this technique to paralyze systems .


  15. WAT

  16. I found this very interesting, follow my website link to learn more on such topics. It is actually interesting to study.

  17. I have downloaded it, but not going to unzip it.

  18. Your blog is interesting!

    Keep up the good work!

  19. Good post. Your messages are really interesting. To have a good site you should not only to add smth, but do it interesting. You managed with it – thanks.

  20. Amazing site.
    Thanks, webmaster.

  21. Cool blog
    Thanks, webmaster.

  22. How do you get rid of a zip bomb?

  23. @Gen Their is nothing called getting rid of a Zip Bomb , What it actually does is puts your computer in a infinite loop of processing and eating up all your storage space as it uncompresses . So if ever you unzip such a zip bomb then best way is to terminate the process .. ctrl+alt+del .. and kill process in Windows and on Linux see the pid of your unzip program using ps -All and then kill

  24. i was just checking ur complete blog today..its really wonderful…u hav really worked hard on it…appreciative work… really gr8 man…keep going…bbye

  25. As a Newbie, I am always searching online for articles that can help me. Thank you Btta5200

  26. I think the compression utility uses some sort of data redundancy, being the data all the same, can be compressed in only 42Kb.

    Oh, anyway if anyone has a better technical explanation would be appreciated, :)

  27. Anyone tried unzipping it?
    I am tempted to, but lazy about installing the OS and all the software again.

  28. Maybe you could edit the blog title Do not unzip this – it is a huge 42 KB file !! | TechStroke to something more catching for your subject you create. I enjoyed the post still.

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