Research at Castle

Our research investigates security, fraud, and bot detection through the lens of deep dive analysis and data science.

Fingerprint harvesting in the bot ecosystem
Published April 22, 2026
Last revised April 22, 2026
Antoine Vastel

This report uncovers how bot ecosystems harvest and reuse real browser fingerprints, including signals from commercial anti-bot systems, to scale realistic impersonation. These fingerprints are becoming operational assets, enabling more efficient and harder-to-detect automation. The implication is clear: detection systems must assume replay and treat client-side signals as untrusted.

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BotmasterLabs: Powering an Era of Spam
Published March 23, 2026
Last revised March 23, 2026
Antoine Vastel, Nicolas Sama, Naif Mehanna, Kurt Nistelberger

How XRumer and XEvil scaled forum spam by combining automation, CAPTCHA solving, and brittle fingerprinting.

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Meet the team behind Castle's security research

Antoine Vastel - Browser fingerprinting, bot detection, web security
Kurt Nistelberger - Mobile security, reverse engineering, device signals
Naif Mehanna - Detection engineering, email intelligence, Hardware fingerprinting
Nicolas Sama - Obfuscation, codec architecture, anti-tampering

Job Opportunities at Castle

• Device Fingerprinting Engineer
  Build fingerprinting systems that survive spoofing, drift, and browser evolution.
• Detection Automation Engineer, Bot & Fraud Detection
  Build detection systems that actually survive contact with attackers.
• Mobile Engineer
  Build mobile SDKs that run reliably inside millions of devices.