As the Obama administration raced to meet its self-imposed deadline for online health insurance markets, security experts working for the government worried that state computer systems could become a back door for hackers. Documents provided to The Associated Press show that more than two-thirds of state systems that were supposed to tap into federal computers to verify sensitive personal information for coverage were initially rated as "high risk" for security problems. Back-door attacks have been in the news, since the hackers who stole millions of customers' credit and debit card numbers from Target are believed to have gained access through a contractor's network.