This rule detects instances of malformed URL prefixes within email content, specifically targeting phishing attempts that exploit common email security vulnerabilities. Malformed URLs, particularly those containing unexpected characters like '\\' in their structure, can trick users and lead them to malicious websites while bypassing typical detection mechanisms employed by email security scanners. The rule uses regex matching to identify any URLs that contain the specified malformed pattern, thereby helping to combat credential phishing and ransomware attacks effectively. Given the rising incidence of such attacks, with reports showing a sixfold increase, this mechanism is crucial for protecting users from phishing and malware threats.