This rule is designed to detect HTML smuggling techniques, specifically through the use of concatenation obfuscation, which is a common tactic used in phishing campaigns and malware delivery. The rule recursively scans through files and archives, identifying potentially malicious HTML files based on specific characteristics. It checks if any attachments have a file extension commonly associated with HTML files (such as .html, .htm, .shtml, and .dhtml) or are classified under general archive types. Additionally, the rule employs content analysis, looking for specific patterns in the file's content that indicate obfuscation using concatenation techniques, particularly strings that conform to known malicious patterns. This combination of file type checks and content-based detections strengthens the efficacy of identifying sophisticated threats that employ HTML smuggling. By utilizing archive and HTML content analysis methodologies, it effectively mitigates risks associated with credential phishing and the distribution of malware or ransomware.