Yesterday, bad news: some versions of Unreal18.104.22.168.tar.gz contain a backdoor because download mirrors have been compromised.. since november 2009! Read the official security advisory for more information. Other websites are reporting the issue, someone even provided a small shell script to fix the flaw: it basically reverts the changes with diff+patch, make clean & make again, so you just have to restart your IRCd. If you're running an UnrealIRCd you should double check your installation because some exploits are already widespread, as well as an NSE (Nmap Scripting Engine) script (seen on nmap-dev mailing list) to scan & kill IRC servers infected by the backdoor.
Oh and funny thing on Yahoo news and techworld (who seems to have copy/pasted yahoo news..):
The good news [...] is that the Trojan is in a game download so it should have no bearing on Linux in a business setting. Unreal is a popular first-person shooter game--similar to Doom or Quake.No, Unreal is not UnrealIRCd. :)
As a curious person I wanted to know more about this backdoor, so let's investigate.