TORONTO - A Canadian-based organization thought to be at the centre of a five-year-long, worldwide cyber attack (http://www.huffingtonpost.com/2011/08/03/cyber-spying-report-china_n_917141.html?ir=Canada) is questioning claims that its systems were compromised and left open to exploitation for more than a year.But the skepticism voiced by the Montreal-based World Anti-Doping Agency is fuelling warnings from security experts, who say the group's doubts only prove that a well-executed hack can escape even the most rigorous security procedures.More... (http://www.huffingtonpost.ca/2011/08/03/operation-shady-rat-canada_n_917736.html)