Enlarge / Ford Mustang Mach E electric vehicles are offered for sale at a dealership on June 5, 2024, in Chicago, Illinois. (credit: Scott Olson / Getty Images)

CDK Global touts itself as an all-in-one software-as-a-service solution that is "trusted by nearly 15,000 dealer locations." One connection, over an always-on VPN to CDK's data centers, gives a dealership customer relationship management (CRM) software, financing, inventory, and more back-office tools.

That all-in-one nature explains why people trying to buy cars, and especially those trying to sell them, have had a rough couple of days. CDK's services have been down, due to what the firm describes as a "cyber incident." CDK shut down most of its systems Wednesday, June 19, then told dealerships that afternoon that it restored some services. CDK told dealers today, June 20, that it had "experienced an additional cyber incident late in the evening on June 19," and shut down systems again.

"At this time, we do not have an estimated time frame for resolution and therefore our dealers' systems will not be available at a minimum on Thursday, June 20th," CDK told customers.