On this screen, a user can enter any Hotmail user name to access the account. Once the username is entered, anyone can send, read and forward e-mail from that account. Hotmail has over 40 million subscribers.

August 30, 1999
Web posted at: 10:37 a.m. EDT (1437 GMT)

(CNN) -- Millions of free Internet e-mail accounts provided by Microsoft's Hotmail service were susceptible to a major security breach that allowed access Monday to users' accounts.

The breach worked via a simple Web address which prompted for a Hotmail username. Once the username was entered, the Hotmail account came up and the mailbox was available.

The hack opened all accounts tested by CNN Interactive, but e-mail messages couldn't always be opened. There was no immediate information on how long the breach has been active.

The breach allows users to read and forward a member's old messages, read new messages and send e-mail in some cases under the name of the user -- assuming the member's identity.

Hotmail boasts 40 million subscribers.

A morning telephone call made to the public relations firm that handles Microsoft's publicity was referred to Microsoft's main number in Redmond, Washington.

That call was forwarded by an operator to Microsoft's Corporate Security Desk. "You should send that to abuse@hotmail.com. " said Greg Betcher, at that desk.

Erik Barkel, of Stockholm, Sweden, was listed in the domain name directory Internic as the administrator for the Web site's domain, but a call to his number did not go through.