Security researchers discovered vulnerabilities in Dell Wyse Thin client devices.

Dell Wyse Thin Clients

Wyse has been developing thin clients since the 90s and was acquired by Dell in 2012.

Vulnerability Summary:

Dell Wyse ThinOS is prone to insecure default configuration vulnerabilities.

However, These vulnerabilities can be exploited by an unauthenticated remote attacker to access a writable file that can be used to manipulate the configuration of a specific thin client.

The INI files contain a long list of configurable parameters.

Reading or altering those parameters opens the door to a variety of attack scenarios.

Likewise, Configuring and enabling VNC for full remote control, leaking remote desktop credentials, and manipulating DNS results are some of the scenarios to be aware of.

CVE-2020-29491 —

CVE-2020-29492 —

Security Recommendations:

According to CyberMDX Research Team,

If your device cannot be upgraded to ThinOS 9.x, it is recommended you disable the use of FTP for obtaining the vulnerable files.

On the ThinOS client desktop

Navigate to System Setup > Central Configuration > General.

Remove any FTP settings present. Where remote management is required, please use other methods – https server or Wyse Management Suite.

Note: Information on configuring those can be found online on Dell’s website.

On your DHCP server

Dell Wyse uses DHCP option tags 161 and 162 to configure the ThinOS client, file server, and path information.

Importantly, Make sure your DHCP server does not reconfigure those back to the FTP server on every DHCP interaction.

Reference:

DSA-2020-281: Dell Wyse ThinOS 8.6 Security Update for Insecure Default Configuration Vulnerabilities. | Dell India