The mean cost of a cybersecurity breach involving employees or others within an organization is $8.7 million, according to a global study of insider threats.

Based on interviews with IT security professionals across more than 700 organizations, the “2018 Cost of Insider Threats: Global Organizations” report, conducted by the Ponemon Institute, benchmarked the common causes of insider incidents over a 12-month period.

While the mean cost of an insider threat is $8.7 million, the survey tallied the maximum cost at nearly $26.5 million. The minimum cost, meanwhile, is still significant at $489,100.

Insiders Cost Organizations Millions

Sixty-four percent of the attacks covered in the survey traced back to the negligent behavior of a staff member or contractor, and the number of such incidents increased to 13.4 from 10.5 two years ago. The average cost of an insider threat is $283,281, according to the report, but this figure can more than double to $648,845 if the incident involves the theft of credentials by an impostor.

Of course, the financial consequences of a cybersecurity breach largely depend on how quickly an organization can discover it and shut down whatever vulnerabilities were exploited. This is an area of weakness across the board: The report revealed that it took organizations an average of 73 days to contain an insider-related incident. Only 16 percent managed to get the threat under control within a month.

The Cost of an Insider Threat Varies by Size, Industry

While insider threats can be an issue anywhere, the study noted several differences depending on the size of the organization and the market in which it operates. Not surprisingly, the financial services sector tends to be hit hardest, with an average cost of $12.05 million. Manufacturing firms, meanwhile, lose an average of $8.86 million per incident.

The larger the firm, the worse it gets: Organizations with 1,001 to 5,000 employees lost an average of $5.79 million to insider threats. Even those with less than 500 employees incurred $1.8 million in such costs.

Negligent behavior is not the only factor contributing to insider threats. The report showed that 23 percent of attacks were deliberately malicious, while 13 percent involved user credential theft.