During Business Email Comproise (BEC) engagements we often have to analyze the provenance of emails. According to the FBI’s Internet Crime Report, BEC is one of the most financially damaging attacks, even surpassing ransomware in terms of losses. But how can we know all of this? Through email headers! This blog post tries to shed some light on the information contained within emails, what it means, and what can be done to prevent this type of attack.