How Redirect Chains Let Malicious Ads Slip Past Ad Blockers

Malicious Google Ads rarely link directly to harmful domains; instead, attackers route users through a series of rapid 302 redirects that cycle through freshly registered domains faster than static blocklists can update. Because traditional blocklists only evaluate the final destination, new domains can be exploited and abandoned before they are ever flagged. Security researchers argue that behavioral signals — such as hop count, timing between redirects, and repeated stripping of referrer headers — are more reliable indicators of malicious activity than domain reputation alone. A Python-based tool has been proposed that follows redirect chains using lightweight HEAD requests, recording timing and header data at each hop to generate a dynamic risk score. The analyzer can be further customized with a YAML configuration file to set hop limits, scoring thresholds, and whitelists for known legitimate ad domains.