Endpoint devices that have Remote Management enabled but are not yet tied to a UMS instance can be taken over by an attacker's UMS. Make sure to register all IGEL endpoint devices on your network
By default, Remote Management is enabled on IGEL OS endpoints. Use Autoregistration to catch all endpoint devices in your corporate network:
Now all new IGEL thin clients and devices converted with UDC3 booting up in the network will automatically register with your UMS instance.
Alternatively you can disable Remote Management in the local IGEL Setup under System > Remote Management. Of course this means losing one of the most powerful features of IGEL OS. However, this may be an option for particular endpoints.