A method includes: identifying, by a runtime instrumentation agent of a web server, a plurality of attack surfaces of a web application executed on the web server; generating, by the runtime instrumentation agent, a plurality of hash values, where each hash value is generated based on one of the plurality of attack surfaces; and transmitting, by the runtime instrumentation agent, the plurality of hash values to an attack server external to the web server, where the attack server is to determine whether to scan each attack surface based on the plurality of hash values.