Table of contents
Key takeaways
- Application security testing (AST) is the set of processes and tools used to find and fix security defects throughout the software development lifecycle.
- Common AST techniques include threat modeling, SAST, SCA, DAST, and IAST. Each identifies different classes of risk.
- Shift-left AST helps teams find issues earlier, when fixes are faster and less disruptive.
- Combining AST findings with cloud and runtime context helps teams prioritize the vulnerabilities that present real business risk.
Application security testing (AST) is how organizations identify security weaknesses before attackers can exploit them. It includes activities such as threat modeling and automated techniques like SAST, SCA, DAST, and IAST. AST belongs in the same program as shift-left security, while DevSecOps practices help route findings to the right owners for remediation.
AST is not a single tool. It is a program that combines testing, remediation workflows, and governance across the software development lifecycle. The goal is to reduce the chance that design flaws, vulnerable dependencies, or insecure defaults reach production.
NIST SP 800-218 (Secure Software Development Framework) provides a widely used framework for integrating security into software delivery. Organizations do not need every control on day one, but they should define a clear scope covering languages, pipelines, environments, and risk owners.
Why AST Matters: The Importance of Shift Left Security
Fix issues earlier. Fixing a defect after release costs more than fixing it during design or code review. That is the core idea behind shift-left security: finding issues when developers still have context and remediation is straightforward.
Security does not stop at deployment. Runtime abuse, supply-chain incidents, and cloud misconfigurations still emerge after release. Programs that only scan repositories can miss exposed admin interfaces, unsafe cloud defaults, and risks introduced during deployment. Pair AST with application security governance so scope covers APIs, batch jobs, and integrations, not only user-facing web apps. Modern APIs also expand the attack surface, making API security testing an important part of AST.
Support secure software delivery. Supply-chain incidents highlight the importance of composition analysis and software integrity. AST programs that include SCA and dependency governance are better equipped to identify risk when upstream packages change. OWASP maintains testing guidance that maps closely to AST programs. The Application Security Verification Standard helps teams translate security requirements into practical test cases for SAST, DAST, and manual review.
Types of Application Security Testing
AST types differ by what they analyze (source, binaries, running systems), when they run (build, test, prod), and what classes of bugs they target. Teams combine them because no single technique finds everything.
The table below summarizes common differences. Your toolchain labels may vary by vendor.
| Technique | Typical inputs | Strengths | Blind spots |
|---|---|---|---|
| Threat modeling | Architecture, data flows | Finds design flaws early | Depends on accurate diagrams |
| SAST | Source or bytecode | Fast feedback in CI | False positives; needs tuning |
| SCA | Manifests, lockfiles, images | Supply-chain and license risk | Transitive dependency noise |
| DAST | Running app URLs | Realistic HTTP attack surface | Auth and workflow coverage |
| IAST | Instrumented runtime + code paths | Taint-style precision | Operational cost and support |
Penetration testing and red-team exercises differ from routine AST. Pen tests simulate adversaries against staging or production-like systems, often with creativity and social elements automated scans skip. Schedule them on a calendar; run SAST and SCA on every merge. The CISA Known Exploited Vulnerabilities catalog helps prioritize fixes when AST and threat intel both flag the same CVE.
Fuzzing feeds malformed inputs to parsers and protocol handlers to find crashes and memory corruption. Projects such as AFL++ are common in C and C++ components. Fuzzing complements SAST for native code but needs build integration and crash triage discipline.
Threat Modeling
Threat modeling identifies attackers, entry points, and valuable assets before code hardens around wrong assumptions. Methods such as STRIDE or PASTA structure discussion between developers, architects, and security. Outputs include data-flow diagrams, trust boundaries, and prioritized misuse cases that later SAST and DAST rules can reflect.
Threat models age. Revisit them when you add identity federation, new external APIs, or AI features that change data lineage. A model that ignores OAuth scopes or service accounts will under-test the real system.
Store models as code or diagrams in the repo next to the system they describe. Review diffs at the same time as architecture changes so security stays a gate, not a quarterly workshop.
Static Application Security Testing (SAST)
SAST analyzes source or compiled code without executing the full application. It finds patterns associated with injection, weak cryptography, hard-coded secrets, and unsafe API use. SAST runs in IDEs and CI pipelines for fast feedback.
To get reliable results from SAST:
- Tune rules and suppressions to reduce false positives.
- Map findings to owners through vulnerability management workflows.
- Validate language coverage against your actual stack, including infrastructure-as-code templates where relevant.
Software Composition Analysis (SCA)
SCA inventories open-source and third-party components, compares versions to known vulnerabilities, and flags license risks. It answers which Log4j line you shipped and whether a fix exists.
Key SCA practices include:
- Generating and storing SBOMs for every release.
- Maintaining policies for private forks and vendored code.
- Applying the same SCA gates to internal mirrors as public registries.
SCA does not replace patching discipline; it makes scope visible when new vulnerabilities emerge.
Dynamic Application Security Testing (DAST)
DAST exercises running applications through their external interfaces, often with crawling and fuzzing. It needs a deployable environment that mirrors auth and routing enough to reach real code paths. DAST finds configuration issues, auth bypasses, and runtime-only flaws that static analysis cannot see.
DAST can miss logic in deep workflows without scripted authentication. Pair it with manual testing or specialized scripts for multi-step business flows.
Rate limits and WAFs affect DAST results. Coordinate scan windows with operations so tests resemble attacker traffic without taking production offline. Prefer dedicated test tenants when available.
Interactive Application Security Testing (IAST)
IAST instruments running applications to combine runtime observation with code awareness. It can trace tainted data from HTTP parameters to sinks, bridging some gaps between SAST and DAST.
Before deploying IAST, consider:
- Runtime overhead and operational ownership.
- Privacy implications if PII flows through traced paths.
- Differences between staging and production routing or test data.
When IAST flags a sink, validate the finding against SAST and DAST results to confirm reachability and exploitability.
How Orca Security Fits Application Security Testing Programs
Adding Cloud Context to AST Findings
AST tools find issues in repositories and test environments, but production introduces additional risk factors such as IAM permissions, public exposure, secrets, and attack paths across accounts. Orca Cloud Security Platform uses agentless SideScanning™ to connect AST findings to real-world exposure, sensitive data, and attack paths across AWS, Azure, GCP, and related services.
That context changes prioritization. A high-severity finding on an isolated build server differs from the same finding on an internet-facing workload with a path to customer data. Orca’s unified risk model complements SAST and SCA signals so security and engineering teams can focus on the findings that matter most.
Orca also supports broader code security and cloud posture goals. Misconfigurations, identity risk, compliance mapping, and vulnerability data appear in a unified view, helping teams validate that remediation efforts reduced risk in deployed environments, not only in source code.
Operationalizing AST in Cloud Environments
For organizations standardizing on a CNAPP approach, Orca provides a single place to relate application findings to infrastructure state. That alignment matters when the same vulnerability appears across multiple services but only one is actually exposed through a misconfiguration or attack path.
Treat Orca as the cloud and workload risk layer, not a replacement for IDE-based SAST or registry-based SCA. Integrating findings across tools helps teams investigate regressions more efficiently and maintain traceability from code to production.
Organizations that already enforce quality gates in CI/CD can extend that model into deployment workflows by requiring review of critical cloud exposures before promotion to production.
Application Security Testing Frequently Asked Questions
Prioritization should combine severity (e.g., CVSS), exploitability, asset exposure (internet-facing vs internal), and data sensitivity. Findings that sit on critical, exposed systems should take precedence over isolated issues.
Not necessarily. Small teams often start with SAST and SCA in CI/CD, then add DAST or manual testing for critical applications. Coverage should expand based on risk and system complexity.
Key indicators include mean time to remediate, percentage of builds blocked by critical issues, reduction in repeat vulnerabilities, and alignment between detected issues and actual incidents.
Application security testing should be integrated throughout the software development lifecycle rather than performed as a one-time assessment. Many teams run SAST and SCA on every code change, perform DAST during testing cycles, and revisit threat models when major architectural changes occur.
Application security testing is an ongoing process that combines multiple techniques to identify vulnerabilities throughout development and deployment. Penetration testing is a point-in-time assessment that simulates real-world attacks against a deployed application to identify exploitable weaknesses.
Chat with an Orca Expert