It was another grim day for internet security at the annual Pwn2Own hacker contest Wednesday, with Microsoft's Internet Explorer, Mozilla's Firefox and Apple's Safari and iPhone succumbing to exploits that allowed them to be remotely commandeered. Like dominoes falling in rapid succession, the platforms were felled in the fourth year of the contest, which has come to underscore the alarming insecurity of most internet-facing software. To qualify for the big-money prizes, the exploits had to attack previously undocumented vulnerabilities to expose sensitive system data or allow the remote execution of malicious code. The exploits were all the more impressive because...