Walter Hop is a software engineer and security/privacy enthousiast from the Netherlands. Walter is a core developer of the OWASP ModSecurity Core Rule Set project, focusing mainly on server-side attacks such as code injection. His code contributions include a complete rewrite of the PHP code injection rules and Unix/Windows/Powershell RCE rules, a user-friendly configuration file format, and resolution of many false-positive alerts.

Walter obtained a M.Sc. Cum Laude in Computational Economics, with a focus on data mining. He has co-founded and managed several companies in the fields of web applications, online medical research, and web hosting. Some of his blogs and disclosures about WordPress (plugin) security were featured on SecurityWeek, ThreatPost, WordFence and FrankWatching.

Currently, he is a CTO at Dutch web app developer Slik, and a security engineer at ModSecurity integrator BitSensor.

When he is not fixing false positives, Walter plays Pokémon Go (Team Instinct FTW) and obsessively studies post-Soviet frozen conflicts. Walter always accepts cookies, but deletes them regularly.