Discovery / credits: Malvuln - (c) 2022  
Original source:  
Threat: Loki RAT (Relapse)  
Vulnerability: Directory Traversal - Arbitrary File Delete  
Description: The LokiRAT WebUI panel for "LokiRAT_Relapse.exe" runs on PHP and MySQL and is used control infected hosts through a central server.  
The admin webpage "admin.php" takes four parameters pass, command, id and type. Theres a single check to authenticate $_GET['pass'] against a hardcoded clear-text password in settings.php.  
The backend "admin.php" code has an upload feature, it uses PHP "unlink" function to delete a file before moving the new one. However, the code does not  
use any secure coding practices, sanitize or filter user input for directory traversal characters "/../". This can allow authenticated users, compromised bots or third-party attackers  
who can guess the password check, ability to delete any file E.g. ".php", ".htaccess" etc in the root panel outside the "uploads/" dir, causing Loki web panel to become inoperative.  
admin.php snippet:  
case "upload":  
$fullfilename = "uploads/" . $_GET['filename'];  
if (file_exists($fullfilename)) unlink ($fullfilename);  
move_uploaded_file($_FILES['file']['tmp_name'], $fullfilename);  
Family: Loki  
Type: WebUI  
MD5: aabb54951546132e70a8e9f02bf8b5ba  
MD5: 16c33e28c8c9b3ea71249ad94be4bf94 (admin.php)  
Vuln ID: MVID-2022-0509  
Disclosure: 03/05/2022  
delete "settings.php" file which holds database connection, rendering the backend inoperative.  
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