How can embedded links trigger security filters?

Security filters scrutinize links for patterns associated with malicious activity. Direct links to executables (.exe, .zip, .scr files) trigger immediate blocking-legitimate businesses rarely distribute software via email links. IP addresses instead of domain names (http://192.168.1.1/page) raise red flags because attackers use raw IPs to avoid domain-based blocking. These patterns are so strongly associated with malware distribution that even legitimate uses get caught.

Excessive redirect chains also trigger security systems. When a link bounces through multiple intermediary domains before reaching the destination, filters suspect obfuscation-a technique attackers use to hide malicious endpoints. Similarly, URL shorteners (bit.ly, tinyurl) can cause problems if the shortening service is associated with spam or if the final destination is suspicious. Some enterprises block shortened links entirely as policy.

Other link-based triggers include mismatched anchor text and URLs (displaying \"bankofamerica.com\" but linking elsewhere-a classic phishing technique), newly registered domains with no reputation history, and domains that resolve to known malicious IP ranges. Clean, direct links to established domains with matching anchor text signal legitimacy; anything that looks like you're trying to hide the destination signals the opposite.