Bank details exposed of past and present staff members
Hundreds of Sure staff members have had their personal information hacked across the Isle of Man, Guernsey and Jersey.
In a statement the telecoms company says it was 'targeted by a phishing attack.'
The scam has affected present and former employees' data, but no customers.
In a letter sent to employees, shown to Manx Radio, stolen data includes names, addresses, bank account numbers and sort codes.
Sure says it has contacted all of those affected, which is said to be fewer than 400 - and says the loss of data was as a result of human error, on one person's email account.
It adds that while the attack was contained, it advises people to be extra vigilant.
Sure has also apologised and reassured people that security is of paramount importance.