EP 61 Sneaky Scam Makes Hidden Changes to Your Email

Recently, when replying to a client's email, we received an email undeliverable response saying that their mailbox was full. However, upon closer review, the email address mentioned didn't belong to my client. We called the client to see if he received my reply. He said "yes." We then asked him if he was familiar with the email address listed on the undeliverable response, to which he said "no." Find out what happened when hidden malicious email rules hijacked our client's emails and what we did to resolve the issue.