Three-quarters of organisations have reported a substantial financial loss arising from cyber-terror, according to research.
The eighth annual Computer Crime and Security Survey from the Computer Security Institute (CSI), produced with the San Francisco FBI's Computer Intrusion Squad, found that 75 per cent of the 530 survey respondents reported financial losses from hack attacks.
The total loss estimated to have been caused by IT security breaches for the organisations surveyed was $455.8m (£276.6m). But CSI pointed out that only 47 per cent of respondents could quantify their loss.
CSI found that more respondents (78 per cent) cited their internet connection, rather than their internal systems (36 per cent), as a frequent point of attack.
Chris Keating, CSI director, said in a statement: "The trends the CSI/FBI survey has highlighted over the years are disturbing. Cyber-crimes and other information security breaches are widespread and diverse. Fully 92 per cent of respondents reported attacks.
"Furthermore, such incidents can result in serious damages. The 251 organisations that were able to quantify their losses reported a total of over $200m.
"Clearly, more must be done in terms of adherence to sound practices, deployment of sophisticated technologies and, most importantly, adequate staffing and training of information security practitioners in both the private sector and government."
In a shift from previous years, CSI found the second most expensive computer crime among survey respondents was denial of service, with a cost of $65.6m - up 250 per cent from last year's losses of $18.4m.
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