U.S. government cybersecurity chief Richard Clarke Friday confirmed plans to quit the post and is bidding farewell with a warning that “sophisticated” hacker attacks could cripple the nation’s IT backbone. In an e-mail to colleagues that was leaked to sections of the media, Clarke said he is leaving to look for a job in the private sector and warned that a sophisticated version of the ‘Slammer’ worm, which wreaked havoc on IT systems worldwide, could be devastating. Clarke characterized the worm as “dumb” and said it was “easily and cheaply made” but warned that Internet vulnerabilities can still be exploited by sophisticated attackers. “As long as we have vulnerabilities in cyberspace and as long as America has enemies, we are at risk of the two coming together to severely damage our great country,” the former counter-terrorism advisor wrote. Full Story