At a hacker conference in Vancouver, techies compete to break into major operating systems.
The world's largest computer chip company, Intel (INTC), says that it was the target of an attack last month at about the same time that Google's servers were hit.
Google is now investigating whether some of its own employees helped carry out the recent cyber-attack in China, which exposed Gmail accounts of U.S. companies and Chinese dissidents. News reports also say foreign reporters based in China were targeted by the hackers, too.
A day after Google said it might quit China after a cyber attack hacked the Gmail accounts of human rights activists there, U.S. Secretary of State Hillary Clinton asked China's leaders for an explanation. Free speech advocates, meanwhile, praised the search giant's decision to remove censorship filters in the country.
The FBI is investigating an alleged cyberattack on Citigroup, apparently from inside Russia, which may have resulted in the theft of tens of millions of dollars. Citigroup denies it was hacked.
Twitter, the Web wunderkind with a $1 billion valuation, was attacked Thursday night by a group calling itself the "Iranian Cyber Army."