The detection rule named 'AnonymousFox Indicators' is designed to identify email messages originating from compromised websites associated with the AnonymousFox threat actor. This is achieved by scrutinizing the sender's email address and specific headers (X-Authenticated-Sender and X-Sender) for patterns indicative of AnonymousFox (specifically, the presence of 'anonymous' or 'smtp' followed by 'fox'). Such patterns suggest potential malicious intent, as these email addresses are often used in phishing attempts, business email compromise (BEC), and other forms of fraud. The rule employs regex-based checks to match the required criteria in the email headers and sender information, classifying threats with high severity based on detected anomalies in email communications. Given the multiple attack types associated with AnonymousFox, which include BEC/Fraud, Credential Phishing, and Malware/Ransomware, detecting these indicators promptly can mitigate risks to organizational security.