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Dynamic Application Security Testing (DAST)

Dynamic Application Security Testing (DAST) is a method of analyzing applications while they are running to detect vulnerabilities that can only be observed during execution.

What is DAST?How it typically works?Common techniquesImpactFurther reading

What is DAST?

DAST, sometimes referred to as black-box testing, simulates an attacker’s perspective by probing applications without access to their internal code. It identifies issues such as SQL injection, cross-site scripting (XSS), authentication weaknesses, and insecure server configurations. Unlike SAST, which scans code, DAST operates against a deployed application, making it ideal for detecting runtime flaws that depend on execution context, inputs, or environment.

How it typically works?

  1. Application crawling: the tool maps exposed endpoints, inputs, and workflows by navigating through the application like a user.
  2. Input injection: crafted payloads are submitted to test how the application handles unexpected or malicious input.
  3. Response analysis: the application’s responses are analyzed to determine if vulnerabilities exist.
  4. Authentication testing: DAST tools evaluate session management, credential handling, and access controls.
  5. Reporting: vulnerabilities are categorized by severity with remediation guidance.

DAST can be integrated into CI/CD pipelines for continuous testing, but it typically runs later in the lifecycle because it requires a functional build or staging environment.

Common techniques

  • Fuzzing: inject random or malformed input to trigger unexpected behavior.
  • Crawling/spidering: automatically explore the application surface for entry points.
  • Authentication testing: evaluate login flows and session expiration.
  • Configuration testing: detect insecure headers, weak TLS settings, or missing patches.
  • API testing: assess exposed APIs for injection flaws and broken authentication.
  • DAST + SAST integration: combine white-box and black-box approaches for stronger coverage.

Impact

DAST helps uncover vulnerabilities that static analysis might miss, such as misconfigured servers or flawed authentication flows. It is particularly valuable for web applications exposed to the internet, where attackers can probe systems directly.

However, DAST may not identify vulnerabilities hidden deep in logic or unreachable endpoints. It can also generate false negatives if coverage is incomplete. For SecOps, DAST complements SAST and SCA, ensuring applications are tested from both inside and outside perspectives.

Further reading

Related topics

SASTSCAWeb Application Firewall (WAF)