This rule detects potential abuse of Google Tag Manager (GTM) debug cookie clearing links within inbound messages. It flags messages containing a hyperlink where the root domain is googletagmanager.com, the path equals /debug/clearcookies, and a decoded query parameter named url is present with a valid domain. This pattern can enable open redirect abuse by steering victims to attacker-controlled destinations via the GTM endpoint. The rule also covers cases where URLs have been rewritten or obfuscated using GTM encoding methods (e.g., google_tag_manager encoders). High severity is justified due to the combination of service abuse and credential phishing risk through redirection to credential collection or malicious sites. Detection methods rely on URL analysis (parsing domain, path, and query parameters) and content analysis (link presence and encoding). The rule is designed for inbound message content and uses data sources related to domain names and network traffic to identify suspicious GTM-based redirect attempts.