This detection rule identifies potential HTML smuggling attacks within email bodies that utilize JavaScript functions such as 'document.write' or 'insertAdjacentHTML' in conjunction with 'atob'. The presence of these functions, along with the specific conditions of the email body length being less than 200 characters or null, raises indications of credential phishing attempts. Such malicious tactics can enable attackers to obfuscate payloads within the email HTML, ultimately designed to capture user credentials through phishing schemes. This rule leverages content and HTML analysis techniques to assess the structure of the email message and detect suspicious activity, thus allowing organizations to respond to threats more effectively.