I'm not sure if it counts as a desktop application, because it used web browsers for its interface. But does anyone remember SATAN, the security scanning tool by Dan Farmer? The back end was all in perl.

I don't know why devlopment was dropped, but apparently it was. Where is Dan these days? I see a Dr. Dobbs article from April, 2001, but that's about it.

Also I see SAINT and SARA, both of which appear to be SATAN spawn, therefore perl based.

Matt