Large enterprises continue to risk leaks from outbound email, blogs, message boards, media sharing sites and mobile devices, according to new research.

Security firm Proofpoint's annual study of outbound email and content security found that large enterprises have still to take action against information leaks over outbound email and other communications.

Outbound email remains the greatest source of risk for European companies. Some 30 per cent of respondents had investigated an email leak of confidential information in the past 12 months.

A third of the largest companies surveyed employ staff to read or otherwise analyse the content of outbound email, and 11 per cent employ staff primarily or exclusively for this purpose.

Almost a quarter of large enterprises are believed to have terminated an employee for violating email policies in the past 12 months.

Nearly a third said that their business had been affected by the exposure of sensitive or embarrassing information in the past 12 months.

Respondents to the survey also indicated significant risk resulting from employee use of blogs, message boards and media sharing sites such as YouTube.

Around 18 per cent of companies surveyed had investigated the exposure of confidential, sensitive or private information from lost or stolen mobile devices in the past 12 months.

Some 12 per cent have disciplined employees for improper use of blogs/message boards in the past 12 months, and five per cent for social network violations.