NOTICE - On August 4 2021, Malwarebytes Endpoint Security reached its End of Life. For more information, see the Malwarebytes Endpoint Security End of Life notice. To upgrade to a supported version of Malwarebytes, see Malwarebytes Endpoint Protection or Malwarebytes for Teams.
The latest version of the Offline Updater can be found here, Offline updater
Run the executable on a system with internet access. This will create a new executable. Then, take the new executable to an offline machine and run it to update Anti-Malware for Business.
However as this is a legacy executable, it is no longer supported.