This rule is designed to detect HTML smuggling techniques, which are often used to facilitate credential phishing or deliver malware through HTML files disguised as benign documents. The detection logic involves recursively scanning email attachments, particularly targeting files with HTML or related extensions, as well as common archive types. It checks if any attachments are less than or equal to 400 bytes in size, enabling the quick identification of possible threats disguised as small document files. The rule further inspects the content of these attachments for the presence of JavaScript identifiers related to 'setTimeout', which is a common method in HTML smuggling attacks. By searching for patterns within the strings that include 'location.href', the rule aims to highlight potential redirects indicative of malicious intent. Through meticulous analysis of file types and their corresponding content, this detection rule enhances the ability to preemptively identify and mitigate risks associated with HTML-based threats.