Title: Stored XSS  
Product: SolarWinds Serv-U FTP Server  
Vendor Homepage:  
Vulnerable Version: 15.2.1 and lower  
Fixed Version: 15.2.2  
CVE Number: CVE-2020-28001  
Author: Jack Misiura from The Missing Link   
2020-10-30 Disclosed to Vendor  
2021-01-21 Vendor releases patched version  
2021-08-02 Publication  
1. Vulnerability Description  
SolarWinds Serv-U FTP server through 15.2.1 does not correctly sanitize and validate the user-supplied directory names, allowing malicious users to create directories that when clicked on (in the breadcrumb menu) will trigger XSS payloads.  
2. PoC  
On a vulnerable Serv-U FTP server installation, create a directory named as such:  
The payload contains ');a=function(b) { alert("XSS"); };a('  
As soon as a user clicks on the directory name in the breadcrumb menu, it will trigger the stored XSS.  
3. Solution  
The vendor provides an updated version (15.2.2) which should be installed immediately.  
4. Advisory URL    
Jack Misiura​  
Application Security Consultant  
9‑11 Dickson Avenue  
1300 865 865  
+61 2 8436 8585  
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