This is the sixth edition of our monthly tracker highlighting email domains linked to fraudulent activity. What this list includes: The domains featured here are those observed in connection with fake account creation and other abuse patterns. These fall into three primary categories:Known disposable email servicesCustom “throwaway” domains registered specifically for fraudLegitimate free email providers with limited anti-abuse protectionsWhy we’re publishing thisMost open-source intelligence on email abuse focuses only on known disposable inbox providers. Because Castle protects real-world websites and apps at scale, we see a much broader picture, including custom throwaway domains attackers register for specific campaigns. By sharing the domains we’ve observed, we aim to help fraud teams expand their visibility into attacker infrastructure and detect threats earlier.