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Decoding eval gzinflate base64_decode

There's a few applications around both freeware and paid that encode files or rather scripts so you can't see or modify the source. These encrypted files can be identified by the starting line which is like:

eval(gzinflate(str_rot13(base64_decode

Then it goes on with a mass of random numbers, letters and characters like 'FZi3ksTWEVJ/hZnITwDvV' and so on.

Note: Please try out the online tool to decode this automatically, do not paste in PHP tags just the eval code.

Online eval(gzinflate(str_rot13 Decoder

Base64 Decoder

Now i'm all for people who wish to keep their code or intellectual property hidden so it's not stolen or modified, but at the same time i do like to know exactly what the given piece of code is doing on my server. Being encrypted like this, it could be doing all sorts of malicious things i don't want happening.

So, lets decrypt it and see if it's all legitimate.

Disclaimer: I don't condone modifying and distributing copyright files, this is simply provided so you can view the plain source to ensure your script isn't doing anything malicious on your property ie server.

Firstly, copy the below code in to Notepad and save it as decrypt.php

<?php
echo "\nDECODE nested eval(gzinflate()) from Taree Internet <www.tareeinternet.com>\n\n";
echo "1. Reading coded.txt\n";
$fp1 = fopen ("coded.txt", "r");
$contents = fread ($fp1, filesize ("coded.txt"));
fclose($fp1);
echo "2. Decoding\n";
while (preg_match("/eval\(gzinflate/",$contents)) {
$contents=preg_replace("/<\?|\?>/", "", $contents); eval(preg_replace("/eval/", "\$contents=", $contents)); } echo "3. Writing decoded.txt\n"; $fp2 = fopen("decoded.txt","w"); fwrite($fp2, trim($contents)); fclose($fp2);
?>

Next step, copy your encoded file to NotePad and save it as coded.txt

Save a blank text file as decoded.txt

Upload all 3 files to the root directory of your server, then set the CHMOD on decoded.txt to 666

You will have:

www.domain.com/decrypt.php - Our decoding script
www.domain.com/coded.txt - A text file with our encoded script
www.domain.com/decoded.txt - A blank .txt file CHMOD to 666

Next up, simply visit www.domain.com/decrypt.php with your browser and you will receive a message "Writing Decoded.txt" and you are done. The decoded.txt file that was blank will now have your plain viewable source code.

Save the text file as original-filename.php and you will have a plain source code version of your encrypted file.