I'm not sure if its the same story but the US Army once used Mac OS for some of its web servers because they were judged the most secure. I cannot remember what third party web server they were using.
I used to work as a federal contractor in 1996-1997. The Army did switch to MacOS for web servers. I'm not sure what Mac web server they used. They tried Windows that got hacked, and they ran Linux but didn't always update it and it got hacked as well. I think they ran some stuff as Root in Linux. The MacOS security model was different from Linux or Windows and supposed to be more secure.
Of course social engineering meant that people can call their help desk and pretend to be someone working on the server to get the password reset. No security software is going to stop a social engineering attack. Also after people get their password reset they forget to change it and leave it "password" and other easy to remember passwords. So weak passwords mean someone can get in without using an exploit but a password dictionary attack.
"The compelling aspect of this story is that as a result of the break-in, the U.S. Army has switched the machines that serve the Army's home page from Windows NT-based PCs to Power Macintosh G3s running WebSTAR from StarNine Technologies."
[edit:] I do love the speculation at the end on if Mac OS X Server will be as good security-wise as Mac OS.
