By John S. McClenahen Vexed by computer viruses? Weakened by worms? Or bugged by other breaches of information security? You are not alone. According to PricewaterhouseCoopers, a provider of tax and other advisory services, 46% of the fastest-growing companies in the U.S. have recently suffered a breach of their information security, despite extra protective steps taken since the Sept. 11, 2001, terrorist attacks. Precautions have included additional spending to protect IT systems and data. PricewaterhouseCoopers surveyed CEOs of 402 privately held product and service companies with annual revenues or sales ranging from $5 million to $150 million. Some 90% of the companies that have had their information compromised had been the victims of computer viruses or worms, with computer hackers (61%) and e-mail (27%) being suspected as the primary ways entry was gained. Unauthorized users and employers were suspected by 7% of the companies. The impact of the breaches varied, with 24% of the companies saying they experienced network downtime, 12% found business applications were unavailable, 10% claimed to have experienced financial losses and 7% reported lost or damaged internal records. "To stem sophisticated adversaries, companies need a continually updated defense, says PricewaterhouseCoopers' Mark Lobel, senior manager, security and privacy services. "The price of being unprepared or underprepared amounted to a loss of hard dollars for eight in 10 companies surveyed -- and the lost time equivalent of more than an extra vacation or sick day for each and every employee in a penetrated company."