TL;DR
SAST inspects the source code of an application to discover potential security vulnerabilities.
DAST tests a running application to identify runtime security issues by simulating attack vectors.
Both methodologies aim to detect security vulnerabilities in software applications, and they’re complementary. SAST focuses on static code analysis, while DAST examines the dynamic behavior of a running application.
In this blog post, we'll dig into SAST and DAST security testing methods, exploring how they work and their core aspects. We'll also see where they overlap and differ and provide guidance on choosing the right tool for your security needs.
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Understanding SAST
What is SAST?
Static application security testing tools don’t execute a program to discover code-level flaws with security implications. Instead, SAST analyzes an application’s source code. This approach enables you to address potential security vulnerabilities early in development, before deployment.
How does SAST work?
As we’ve seen, SAST works by scanning application source code, which it then compares to a database of known security vulnerabilities. It uses techniques like pattern matching, control flow analysis, and data flow analysis to identify security holes in the code.
SAST tools function like code linters but focus on security rather than general coding best practices. They can scan source files at different stages of development—early on with IDE integration or during deployment with CI/CD integration.
One thing to keep in mind: To be effective, your chosen SAST tool must support the programming language and framework used by your application.
Key aspects of SAST methodology
Shift-left security: By performing code security assurance as early as possible in the software development lifecycle, you can reduce risks before deployment.
IDE integration: SAST tools seamlessly integrate with IDEs, helping developers spot security issues as they write code.
Focus on code quality: By highlighting issues directly in the application source code, SAST also enhances code quality.
Understanding DAST
What is DAST?
Dynamic Application Security Testing (DAST) checks for runtime vulnerabilities by testing a running application. DAST tools simulate attacks to uncover weaknesses that attackers could exploit. This method finds security issues in a deployed application and provides insights on strengthening defenses against real-world threats.
How does DAST work?
DAST works by interacting with an application in execution to reveal security vulnerabilities. It uses techniques such as input validation testing, where malicious input is sent to observe how the application handles it.
A DAST tool behaves like a malicious user, studying how an application reacts to various types of attacks. It discovers issues like poor configurations that attackers could abuse to compromise your system or steal data.
DAST tools typically operate as standalone applications, providing an intuitive UI for configuring tests and reviewing results. They produce detailed reports on exposed security breaches and offer recommendations for remediation.
Key aspects of DAST methodology
Shift-right security: By testing an application during or after deployment, you can identify security issues that are actually present, rather than just potential vulnerabilities.
Attack simulation: DAST involves simulating real attack vectors, such as token authentication forgery or cross-site scripting.
No access to source code: DAST tools examine running applications, so they’re programming-language agnostic.
Environment-specific testing: DAST helps to test applications in different deployment environments, from staging to production, to identify environment-specific vulnerabilities.
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SAST vs. DAST: How do they compare?
| Comparison | SAST | DAST |
|---|---|---|
| Focus | Static application source code | Running applications |
| Goal | Identify code-level vulnerabilities early in the development process | Uncover runtime vulnerabilities during or after deployment |
| Programming-language specific? | Yes | No |
| Key capabilities |
|
|
| Attack-vector coverage | Code vulnerabilities, including:
| Runtime vulnerabilities, including:
|
| Ideal use cases |
|
|
Using SAST and DAST together
SAST and DAST test an application at different stages of the development process and in different conditions, so nothing stops you from using them together. Leveraging a combination of SAST and DAST elements is called interactive application security testing (IAST).
To get the most out of the two security testing methodologies, let’s take a closer look at their relationship.
Overlaps
Security vulnerability databases: Both SAST and DAST rely on vulnerability databases and industry standards like the OWASP Top 10 and the CWE Top 25. These resources are used to identify, classify, and report security issues in both static and dynamic analysis.
CI/CD Integration: SAST and DAST tools can integrate with CI/CD pipelines, enabling continuous security testing throughout the software development process. CI/CD integration guarantees timely detection of vulnerabilities before an application goes live.
Reporting: Both SAST and DAST provide detailed reports on identified vulnerabilities. These include descriptions, severity levels, and remediation tips, helping developers tackle security issues.
Differences
Testing approach: SAST inspects code statically without executing it, focusing on code-level issues. In contrast, DAST tests running applications by simulating attacks to identify runtime vulnerabilities.
False positives: SAST is prone to generating false positives because it may not fully understand the context the code lives in. Alternatively, DAST tends to produce fewer false positives as it targets a running application through simulations of real attacks.
Skills involved: SAST requires knowledge of programming languages and the application source code. DAST, on the other hand, assumes a deep understanding of how the application works and behaves, with no coding skills involved.
How to choose between SAST and DAST
If your organization is going to prioritize one method over the other, consider these factors:
1. Security maturity
Mature security users: For development teams skilled at understanding secure code, SAST can significantly reduce the risk of introducing potential vulnerabilities into your applications.
Early security users: If your organization is newer to security best practices, DAST is a better choice because it requires less technical knowledge.
2. Detection time
Early detection: Choose SAST to prevent security flaws as early as possible during development, even if you might get some false positives.
Late detection: If you prefer to catch vulnerabilities directly in a live environment and limit false positives, opt for DAST.
3. Resources and budget
Cost-effectiveness: SAST tools are generally cheaper and less complex than DAST tools. They integrate directly into the IDE and require fewer resources to perform their analysis. Some of these security tools are open source.
General effectiveness: DAST tools are more sophisticated and usually much more expensive than SAST tools. They require the application to be running, which demands more resources. However, DAST produces more accurate results.
4. Scalability
Team scalability: SAST helps to scale security best practices across multiple projects, especially if they all use the same technology stack.
Application scalability: DAST tools can natively integrate with any application, regardless of the programming language or frameworks used.
5. Application knowledge
Code knowledge: If you have a deep understanding of the application’s codebase, SAST is the best approach to gain security insights early in development.
Application behavior knowledge: If you are more familiar with how your application should behave while interacting with it, DAST is the better approach.
Boost your code security with Wiz
As we’ve seen, you don't have to decide between SAST and DAST. That’s because the two security testing methodologies can complement each other. SAST focuses on detecting issues in the codebase, identifying bad implementation choices and code smells, while DAST identifies runtime vulnerabilities that arise from misconfigurations or risky security assumptions.
Relying on only one—SAST or DAST—limits your security coverage. Combine both to create a robust strategy that protects your applications from all angles. Still, it’s a good idea to begin with one and gradually integrate the other.
Wiz provides a range of essential code security features, including software composition analysis, IaC scanning, code and CI/CD security posture, and secret scanning. Then, through our partnership with Checkmarx, you can integrate SAST capabilities into the Wiz cloud platform for a fully featured code-to-cloud security solution.
Wiz - Checkmarx SAST integration
The Wiz - Checkmarx SAST integration combines the strengths of Wiz's cloud-native application protection platform (CNAPP) with Checkmarx's static application security testing (SAST) capabilities. Here's an overview of the integration:
1. Improved Application Security: By integrating Checkmarx SAST with Wiz, organizations can enhance their application security by detecting security vulnerabilities early in the software development lifecycle (SDLC). SAST focuses on analyzing application source code for vulnerabilities, which complements Wiz's broader cloud infrastructure security coverage.
2. End-to-End Visibility: This integration provides comprehensive visibility across both the application layer (via SAST) and the cloud infrastructure (via Wiz). Developers and security teams can now track vulnerabilities from code to cloud, ensuring security is baked into every layer of the application lifecycle.
3. Streamlined DevSecOps: Integrating SAST into the DevSecOps pipeline becomes more streamlined, enabling automated security scans within the CI/CD process. This ensures faster remediation of vulnerabilities, reducing the time security issues persist in the application and production environments.
4. Contextualized Risk Management: Wiz's risk-based prioritization capabilities allow vulnerabilities detected by Checkmarx to be contextualized within the broader cloud environment. This means that risks are prioritized not just based on the severity of the code issue, but also considering the cloud environment, helping teams focus on the most critical vulnerabilities that pose the greatest threat.
5. Unified Dashboard: The integration enables security teams to manage both application security vulnerabilities and cloud infrastructure risks from a unified dashboard in Wiz, improving the overall security posture and reducing the operational complexity of managing multiple tools.
More than 40% of the Fortune 100 trusts Wiz to detect security issues early, prioritize risks, and provide remediation guidance to developers. Secure your application at every stage—schedule a demo today.
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