This rule is designed to detect and flag messages that reference the W-8BEN tax form, which is often utilized in tax-related fraud schemes targeting both individuals and businesses. The detection logic operates on inbound messages where several conditions must be met to trigger an alert. Firstly, the presence of links in the message body is examined, specifically ensuring there are between 1 and 19 links, with at least one of them being relatively new (registered within the last 60 days). Additionally, the rule checks that fewer than 10 unique root domain links are present, and none of these domains should match the sender's domain. Further validation involves ensuring the sender's domain matches the return path domain. The subject line must contain keywords indicative of tax forms, such as "Foreign Tax" or "W-8BEN". The rule also evaluates the message's content for the presence of various tax-related terms, which could indicate fraudulent intent. Another layer of scrutiny involves identifying links registered in China, which is a common characteristic of fraudulent schemes. Lastly, it checks if the sender's email is using nameservers indicating a connection to Alibaba Cloud, which may further strengthen the suspicion of fraud. This multi-faceted analysis aims to detect spear phishing and Business Email Compromise (BEC) attempts effectively.