Beckhoff: Denial-of-Service vulnerability in the IPC-Diagnostics package included in TwinCAT/BSD operating system

By default, TwinCAT/BSD-based products have a device-specific web interface for web-based management
(WBM) enabled, developed by Beckhoff and known as Beckhoff Device Manager UI. It can be accessed remotely
or locally. When accessed locally, a user can post specifically crafted input which then lets the process
'MDPWebServer' consume a maximum of CPU cycles and Random Access Memory (RAM).

A local, low privileged attacker could cause a denial-of-service.

Avoid the existence of user accounts with login permission on the target other than administrator access. By default, TwinCAT/BSD has preconfigured user accounts with lower privileges, but none of them have a password, which results in them being denied login access. Avoid running third-party applications on the target that have not been properly audited, regardless of the user they are running as.

Please update to a recent version of the affected product. In general, Beckhoff recommends updating the entire TwinCAT/BSD operating system to a current version rather than individual packages. Information on updating existing TwinCAT/BSD installations is available in here:. There you will also find information on how to determine the operating system version via the command line. This is also visible via the Beckhoff Device Manager UI. Please note that when updating from the TwinCAT/BSD major version 12, two consecutive upgrades are required.