Understanding DAST Technology

DAST operates by sending requests to running applications and analyzing responses to identify security vulnerabilities. Think of DAST as an automated penetration tester that systematically probes every input point, tests various attack payloads, and observes application behavior to detect security flaws. This black-box approach requires no access to source code, making it valuable for testing third-party applications, legacy systems, or situations where code access is restricted.

The core of DAST technology involves crawling, fuzzing, and attack simulation. Crawlers automatically discover application endpoints, forms, and parameters by following links and analyzing client-side code. Fuzzers generate test inputs designed to trigger vulnerabilities, from simple SQL injection attempts to complex business logic manipulation. Attack simulation engines chain multiple techniques to identify sophisticated vulnerabilities that require specific sequences of actions.

Modern DAST tools have evolved significantly from early web scanners. They now understand complex JavaScript applications, REST and GraphQL APIs, single-page applications, and WebSocket communications. Machine learning helps identify application structure and optimize testing strategies. Some tools can even authenticate into applications and maintain session state to test protected functionality.