In depth
Static Application Security Testing (SAST) tools analyse an application's source code, byte code or binary without running it, looking for taint-flow paths from untrusted inputs to sensitive sinks, insecure cryptographic primitives, hardcoded secrets, dangerous API usage and known vulnerable patterns. Modern SAST tooling — Semgrep, CodeQL, SonarQube, Checkmarx, Fortify, Veracode — runs as a pre-commit hook, in CI on every pull request, or on a scheduled scan of the default branch, and feeds findings into the developer's pull-request review or into the central application-security backlog.
The big advantage of SAST is that it runs before the code ships. A taint path from an unsanitised HTTP parameter into a string-concatenated SQL query can be caught before the function ever serves a request. The big disadvantage is false-positive rate: language-aware tools still struggle with reflection, dynamic dispatch, framework-specific sinks, and the kind of safe-by-construction patterns that look dangerous in isolation. Tuning the ruleset and writing project-specific rules (Semgrep is unusually good at this) is what separates an effective SAST programme from a noisy one.
SAST sits alongside DAST (dynamic testing of the running application), IAST (instrumented runtime testing inside the application), and SCA (Software Composition Analysis — finding known-CVE dependencies). No single tool covers the full attack surface; mature programmes layer SAST + DAST + SCA + manual review and require a security PR review only when a finding is above a certain severity threshold. Industry data consistently puts the cost of fixing a SAST-caught defect at less than a tenth of the cost of fixing the same defect after release.
Frameworks that mandate SAST coverage include PCI DSS v4.0 Requirement 6.2.4, OWASP ASVS V14.2 (Dependencies), and ISO 27001:2022 Annex A.8.28 (Secure coding). See VAPT services for SAST findings layered into a full assessment.
The big advantage of SAST is that it runs before the code ships. A taint path from an unsanitised HTTP parameter into a string-concatenated SQL query can be caught before the function ever serves a request. The big disadvantage is false-positive rate: language-aware tools still struggle with reflection, dynamic dispatch, framework-specific sinks, and the kind of safe-by-construction patterns that look dangerous in isolation. Tuning the ruleset and writing project-specific rules (Semgrep is unusually good at this) is what separates an effective SAST programme from a noisy one.
SAST sits alongside DAST (dynamic testing of the running application), IAST (instrumented runtime testing inside the application), and SCA (Software Composition Analysis — finding known-CVE dependencies). No single tool covers the full attack surface; mature programmes layer SAST + DAST + SCA + manual review and require a security PR review only when a finding is above a certain severity threshold. Industry data consistently puts the cost of fixing a SAST-caught defect at less than a tenth of the cost of fixing the same defect after release.
Frameworks that mandate SAST coverage include PCI DSS v4.0 Requirement 6.2.4, OWASP ASVS V14.2 (Dependencies), and ISO 27001:2022 Annex A.8.28 (Secure coding). See VAPT services for SAST findings layered into a full assessment.