An Apple system engineer's challenge to hack into a web page hosted by a Mini Mac is closed - and nobody was able to succeed.

Dave Schroeder, the University of Wisconsin employee who launched the contest this week after he was unimpressed by a similar challenge because it gave participants local client access to Mac OS X, closed his challenge around midnight today, two days ahead of schedule.

"The response has been very strong, and the test has illustrated its point," Schroeder said on the test web site. "There were no successful access attempts of any kind, including during the 38-hour duration of the test period, nor have there been any claims of success. The host is still the same host and configuration used for the test."

He said the site was accessed roughly 500,000 times and received more than 4,000 login attempts through SSH, a tool that provides encrypted connections for accessing network machines.

The site faced two brief periods of DoS attacks and received several social engineering attempts.

Schroeder has said Macs may be vulnerable to privilege escalation but they are "very secure" because of their open-source components.