The detection rule identifies malicious attachments containing links with UNC (Universal Naming Convention) paths, which can potentially be used to exploit NTLM authentication vulnerabilities. When a link file with a UNC path is attached to a message (such as an email), it can facilitate credential phishing attacks by leveraging the automatic authentication mechanism of Windows, where the system attempts to access the UNC path even before the user opens the file. The rule uses a combination of regex patterns to detect standard UNC paths as well as percent-encoded UNC paths in file attachments with extensions such as '.lnk' or '.url'. If such patterns are matched within incoming attachments, the rule flags them as a medium-severity threat due to their potential in credential phishing scenarios.