DAST VS SAST in '24: Discover Frontiers of Application Security

Developers and security professionals constantly seek more effective ways to safeguard software with the rise of cyber threats. Two pivotal approaches in this quest are Static Application Security Testing (SAST) and Dynamic Application Security Testing (DAST). Though distinct in their operation, these methodologies are integral components of a comprehensive application security strategy.

This article compares DAST and SAST, unraveling their strengths, and limitations. By comparing these two methodologies, this article provides insights into their complementary roles in application security and guides developers and security experts in choosing the right tools and strategies for their specific needs.

What are DAST and SAST?

DAST (Dynamic Application Security Testing): This black-box security testing approach involves testing an application during its running state, hence the word dynamic. It’s used to identify vulnerabilities that an attacker could exploit in a live application, such as authentication, authorization, data validation, and session management issues. DAST is typically performed after the application is deployed.

SAST (Static Application Security Testing): This is a white-box testing methodology where the application’s source code, byte code, or binary code is analyzed to find security flaws without executing the program, hence the word static. It’s done at the development phase, making identifying and fixing issues early in the software development life cycle easier.

In addition to DAST, SAST, and Interactive Application Security Testing (IAST), many application security tools combine these methodologies to detect security vulnerabilities. These tools are often referred to as simply DAST tools.

Why is SAST important?

Static Application Security Testing (SAST) as a testing methodology is vital because it identifies security vulnerabilities in software at an early stage. By analyzing source code before deployment, SAST helps prevent security breaches and ensures compliance with security standards. This proactive approach integrates security into the software development process, reducing the risk and cost associated with fixing issues later. It is one of the testing methodologies that allows for comprehensive application security testing. It can be integrated into the software development lifecycle.

Why is DAST important?

Dynamic Application Security Testing (DAST) is important as it tests software for security vulnerabilities during runtime, simulating real-world hacking attacks. This approach helps identify issues like authentication and authorization weaknesses, which are difficult to detect in static code analysis. DAST provides a practical perspective on how an application behaves under attack, enabling developers to address security flaws in a live environment and enhance the overall security of the software.

How widely used are SAST and DAST?

According to GitLab’s 2022 Global DevSecOps Survey, the usage of SAST (Static Application Security Testing) and DAST (Dynamic Application Security Testing) among developers is quite significant. Approximately 53% of developers reported running SAST scans, an increase from less than 40% in 2021. Similarly, 55% of developers indicated they run DAST scans, up from 44% in the previous year​.¹

When should you use DAST vs. SAST?

Both SAST and DAST are important in a comprehensive application security strategy, and they complement each other to provide a more thorough analysis of security vulnerabilities. Deciding when to use Dynamic Application Security Testing (DAST) versus Static Application Security Testing (SAST) depends on various factors, including the stage of the development lifecycle, the type of application, and the specific security needs of the project.

1. Stage of Development

• SAST:
  • When: Early in the development lifecycle, ideally during the coding phase.
  • Why: SAST can identify vulnerabilities in the source code before the application is running. It’s more efficient to fix security issues at this stage.
• DAST:
  • When: Later stages, typically after the application is deployed in a staging or similar environment.
  • Why: DAST requires a running application to simulate real-world attacks and identify vulnerabilities that only appear during runtime or in fully integrated environments.

2. Type of Vulnerability Detection

• SAST:
  • Detects: Code quality issues, syntax errors, vulnerabilities related to insecure coding practices, and issues that are static in nature.
  • Suitable For: Analyzing the internal structure of the application without needing it to run.
• DAST:
  • Detects: Issues that manifest at runtime, including misconfigurations, authentication and session management problems, and operational environment issues.
  • Suitable For: Applications that are already running, to test from an external perspective.

3. Type of Application

• SAST:
  • Useful For: Almost all types of applications, regardless of the architecture or platform.
  • Benefits: Can be integrated directly into development environments and version control systems.
• DAST:
  • Useful For: Web applications and services that can be accessed over a network.
  • Benefits: Tests the application in an environment that closely resembles how end-users will interact with it.

4. Feedback and Reporting

• SAST:
  • Provides: Immediate feedback to developers, which is useful during the development and debugging phases.
  • Reports On: Specific lines of code and the context around the security issue.
• DAST:
  • Provides: Feedback on how the application behaves under attack-like conditions.
  • Reports On: How the application responds to various external inputs and attack vectors.

5. Integration with Development Processes

• SAST:
  • Best Integrated With: Continuous Integration (CI) environments for early detection of vulnerabilities.
• DAST:
  • Best Integrated With: Continuous Deployment/Delivery (CD) environments to test applications in a state close to production.

External Links

• 1. “2023 Global DevSecOps Report Series What’s next in DevSecOps” GitLab