Title: Path traversal

 

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-2020-27994

 

Author: Jack Misiura from The Missing Link 

 

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

 

Timeline:

 

2020-10-28 Disclosed to Vendor

2021-01-21 Vendor releases patched version

2021-08-02 Publication

 

1. Vulnerability Description

 

SolarWinds Serv-U File Server through 15.2.1 does not correctly validate path information, allowing the disclosure of files and directories outside of the user's home directory via a specially crafted GET request.

 

 

2. PoC

 

On a vulnerable Serv-U installation issue the following GET request to get a listing of files and directories above the user's directory:

 

https://<serv-u host>/Web Client/?Command=List&dir=\..\*.*

 

The user *MUST* be locked to their directory, and only access granted must be the said directory. Directory listing must be enabled. If any of the above is not present, the exploit will not work.

 

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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