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.
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 Quote:
<?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);
?>
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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.
Decoding eval gzinflate base64_decode 
Good script 
Linear Mode
