66 percent of security professionals at U.S. companies with more than 500 employees say they have investigated or worked on a breach that was not disclosed by their organizations. 57 percent said they had worked on data breach that went unreported, according to a survey of 200 security professionals by OpinionMatters. Some 67 percent say malware complexity is the hardest part of protecting their networks; 67 percent, the volume of malware attacks; and 58 percent, ineffective anti-malware products. 40 percent of IT pros say one of their biggest challenges is they don’t have the security staff resources they need.”]