OS / TCP TTL Mismatch

Detection approach

The client's HTTP User-Agent claimed one operating system (e.g. Windows), but low-level TCP SYN packet analysis revealed an execution stack belonging to a different OS (e.g. Linux/Unix). This is a definitive fingerprint of emulators or desktop proxy configurations running under forged headers.

How this helps detect bots

This signal is assessed with other independent session, browser, and network evidence. A single anomaly is a lead, not a verdict; corroborating anomalies make automated traffic more likely.

Legitimate traffic to consider

Web developers explicitly spoofing their User-Agent strings using browser extensions for responsive site testing.