Static Analysis vs Dynamic Analysis
Static analysis examines code without executing it; dynamic analysis tests a running application. Both find different classes of vulnerabilities and work best in combination.
- 1.Core Distinction
- 2.Static Analysis Strengths
- 3.Static Analysis Limitations
- 4.Dynamic Analysis Strengths
- 5.Dynamic Analysis Limitations
Core Distinction
Static analysis examines code without executing it. Dynamic analysis tests code by running it. Both are forms of software testing; they find different things and work at different points in the development lifecycle.
| Property | Static Analysis | Dynamic Analysis |
|---|---|---|
| Code runs? | No | Yes |
| When run | Pre-execution (commit, CI) | Post-deployment (QA, staging, production) |
| Coverage | 100% of code paths | Only exercised paths |
| False positives | Higher (no runtime context) | Lower (observes actual behavior) |
| False negatives | May miss runtime-only issues | Misses untested code paths |
| Speed | Fast (seconds to minutes) | Slower (requires running app) |
| Environment needed | Source code only | Running application |
| Examples | SAST, linting, SCA | DAST, fuzzing, penetration testing |
Static Analysis Strengths
- Runs on every code change — no running environment required
- Covers 100% of code paths, including paths tests do not reach
- Catches vulnerabilities before they reach production
- Scalable — same tool analyzes the full codebase continuously
Static Analysis Limitations
- Cannot observe runtime behavior — misses vulnerabilities that only manifest under specific conditions
- Higher false positive rates — the tool cannot observe actual behavior to confirm findings
- Dynamic language analysis is imprecise — without types and runtime values, analysis is approximate
Dynamic Analysis Strengths
- Observes actual application behavior — findings are confirmed by actual execution
- Catches runtime-only vulnerabilities: race conditions, serialization issues, environment-dependent behavior
- Lower false positive rates — if the analysis found it, it can actually be triggered
- Finds vulnerabilities in third-party components and black-box systems
Dynamic Analysis Limitations
- Requires a running application — cannot run on code before it is deployed
- Coverage limited to exercised paths — untested code is not analyzed
- Slower feedback — cannot be in the pre-commit or PR pipeline as easily
Using Both
The most comprehensive security programs use static and dynamic analysis as complementary layers: static analysis in CI to catch issues before production; dynamic analysis in QA and staging to find runtime behavior issues that static analysis misses. The combination provides broader coverage than either approach alone.
Connection to Autonomous Code Governance
Hydra primarily operates in the static analysis layer — continuously scanning source code before execution. This is by design: static analysis is where autonomous remediation is most powerful because issues can be caught and fixed before they ever run. Dynamic analysis findings from DAST or penetration testing can be fed into Hydra's remediation pipeline, where they are correlated with static analysis findings to identify and fix the root cause in source code.
Frequently Asked Questions
Can static analysis replace dynamic analysis?
No. Static analysis is highly effective at finding a class of vulnerabilities in code but cannot observe runtime behavior. Dynamic analysis finds vulnerabilities that only manifest when the application is running under specific conditions. Both are needed for comprehensive coverage.
What is IAST and how does it relate to SAST and DAST?
IAST (Interactive Application Security Testing) instruments the running application with agents that observe behavior from the inside during normal test execution. It combines aspects of SAST (code-level insight) and DAST (runtime observation). IAST has lower false positive rates than SAST and broader coverage than DAST but requires instrumentation of the application.
Stop flagging. Start fixing.
Hyrax reviews your pull requests, remediates issues autonomously, and closes the ticket.
Join the waitlist