Title: Stored XSS

 

Product: SolarWinds Serv-U FTP Server

 

Vendor Homepage: https://www.solarwinds.com/

 

Vulnerable Version: 15.2.1 and lower

 

Fixed Version: 15.2.2

 

CVE Number: CVE-2020-28001

 

Author: Jack Misiura from The Missing Link 

 

Website: https://www.themissinglink.com.au

 

Timeline:

 

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:

 

%27%29%3Ba%3Dfunction%28b%29%20%7B%20alert%28%22XSS%22%29%3B%20%7D%3Ba%28%27

 

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

 

https://www.themissinglink.com.au/security-advisories

 






Jack Misiura​


Application Security Consultant




a



9‑11 Dickson Avenue


Artarmon


NSW


2064



p


1300 865 865



os


+61 2 8436 8585



w


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