built-in anti mirc exploit doesn't work

[Stealth]

Opers cannot trigger spamfilters. You should try with a second connection as a normal user.

If you need to block DCC exploits, you can try Syzop's AntiDCCBug module, which works perfectly.

From what I know, the spamfilters included with Unreal work well. If you still have problems with the DCC exploits, you should encourage your clients to upgrade