A misfired attempt by one subscriber to change the email address he used for receiving messages caused a storm in the US Department of Homeland Security’s mailing list.

Instead of sending a message to the list administrators, job-changing security consultant Alex hit the reply-to-all button. His message was sent to every subscriber of the DHS’s Daily Open Source Infrastructure Report. Attempts to recall this message were futile.

At first several people began firing off tetchy don’t reply-to-all messages, which were, of course, sent to everyone on the list. Quickly this led to the disclosure of the email addresses of fellow members of the list, addresses that are normally hidden in the DHS’s daily updates.

And it rolled merrily downhill from there.