Guernsey Police are warning local businesses about an online scam targeting users of Office 365.
Officers have been in contact with several businesses using the service who have fallen victim to phishing scams which have allowed hackers access to their email inbox.
The hackers then distribute malicious links to their contacts.
Police say using multi-factor authentication can help keep personal data safe.
Anyone who receives an unexpected email from someone they trust containing a link should contact them directly to make sure they sent it.