The study, carried out by data security specialist Imperva, found that whilst 82% of respondents said that breaches such as WikiLeaks made them reconsider their company's data security policies, just 18% said they were aware of how many sensitive files they had.
According to Imperva, almost one third of those polled reported that their company had lost data due to employees abusing access rights, on purpose or by accident.
"The first step to a solid data security plan is taking inventory of your sensitive files and knowing where they are and who has access to them at all times", said Amichai Shulman, Imperva's CTO, commenting on the survey results.
"Only with this complete picture will you be able to guard against insider threat by detecting when sensitive data is being added or removed, or when an employee is improperly accessing files", he explained.
Shulman went on to say that major data breaches like WikiLeaks happen because of a lack of effective file security controls.
"With so many respondents unsure of how many sensitive files they have and how accessible they are, it indicates a general lack of control over sensitive data, which increases the likelihood of an insider breach", he said.