I was recently hacked, probably due to visiting a not-so-friendly website. From reading my logs I am guessing a dhclient vulnerability was used (see http://www.kb.cert.org/vuls/id/107886 ). I am not sure it is this, but in any case I can't find any information on closing this vulnerability on Ubuntu Server.
Any suggestions? Also, does anyone have tips on preventing other common exploits to DHCP/DNS/etc services?