Here are the details of this incident. Doesn't look like a big deal ... they found it right away and fixed the problem.

Looks like it was at a corporation and they allowed Gentoo to also use the server for rsyncs. The bad guy may have been just trying to take over the box an it may have been a coincidence that this box also happened to be a gentoo server ...

I wonder if it was the same exploit as the Debian servers?