In the run-up to the 2020 census, the government has embraced technology as never before, hoping to halt the ballooning cost of the decennial head count. For the first time, households will have the option of responding online, and field workers going door to door will be equipped with smartphones to log the information they collect.

To make it all work, the Census Bureau needed more computing power and digital storage space, so it turned to cloud technology provided by Amazon Web Services.

What the bureau didn’t realize — until an audit last year — was that there was an unsecured door to sensitive data left open. Access credentials for an account with virtually unlimited privileges had been lost, potentially allowing a hacker to view, alter or delete information collected during recent field tests.

The Census Bureau says that it has closed off this vulnerability and that no information was compromised. But the discovery of the problem highlights the myriad risks facing next year’s all-important head count.