What is Dynamic Application Security Testing (DAST)?

What is dynamic application security testing?

Dynamic Application Security Testing (DAST) is a type of application security testing that focuses on identifying vulnerabilities in running applications—that is, applications that are actively executing in a production or test environment. Unlike static analysis (which examines source code), DAST evaluates the behavior of the application while it is running to find vulnerabilities that could be exploited in real-world attacks.

What is the purpose of dynamic application security testing?

The purpose of Dynamic Application Security Testing (DAST) is to identify and mitigate security vulnerabilities in running applications by testing them in a real-world environment. Unlike static testing, which focuses on source code, DAST evaluates the application’s behavior during execution to detect vulnerabilities that could be exploited during operation.

Here are the key purposes of DAST:

1. Identify Vulnerabilities in Running Applications

• Purpose: DAST helps detect vulnerabilities that only appear when an application is running. This includes issues such as SQL injection, cross-site scripting (XSS), authentication flaws, and misconfigurations.
• Benefit: By identifying vulnerabilities in a live environment, DAST helps prevent attackers from exploiting these weaknesses in real-world scenarios.

2. Simulate Real-World Attacks

• Purpose: DAST tools simulate attacks on an application in the same way a malicious actor would, testing the application’s defenses against typical threats.
• Benefit: This black-box testing approach allows security teams to assess how the application behaves under attack without needing access to the source code, providing a clear picture of how the application would perform in a real attack.

3. Improve Application Security Posture

• Purpose: By continuously testing applications for security flaws, DAST helps organizations improve their overall application security.
• Benefit: DAST makes it easier for development and security teams to identify, prioritize, and fix vulnerabilities before they can be exploited, improving the application’s resilience to cyber threats.

4. Support Continuous Integration/Continuous Deployment (CI/CD)

• Purpose: DAST can be integrated into CI/CD pipelines, enabling automated security testing throughout the software development lifecycle.
• Benefit: This ensures that security is considered at every stage of development, helping teams to detect vulnerabilities early, reduce manual testing efforts, and deliver more secure software at a faster pace.

5. Ensure Compliance with Security Standards

• Purpose: DAST helps organizations adhere to industry security standards and regulations (e.g., OWASP Top 10, PCI DSS, GDPR).
• Benefit: By identifying common security vulnerabilities and ensuring compliance, DAST aids in meeting regulatory requirements and avoiding potential fines or penalties related to security breaches.

6. Detect Security Misconfigurations and Insecure APIs

• Purpose: DAST also helps detect security misconfigurations (e.g., default credentials, exposed sensitive data) and weaknesses in APIs (Application Programming Interfaces).
• Benefit: This is crucial for modern applications that rely heavily on APIs, as insecure APIs are a common attack vector that could be exploited to access or manipulate sensitive data.

7. Offer Insights into Application Behavior Under Attack

• Purpose: DAST provides insights into how an application behaves when attacked and how it handles malicious input, such as incorrect data formats or invalid user actions.
• Benefit: Understanding how an application reacts under attack allows organizations to improve their incident response procedures and fix issues before they are exploited.

The primary purpose of Dynamic Application Security Testing (DAST) is to ensure that applications are secure and resilient to attacks in a real-world environment. By detecting vulnerabilities through simulation of actual attack scenarios, DAST helps organizations improve their application’s security posture, adhere to industry standards, and proactively address security risks during development and deployment.

What is the difference between DAST and SAST?

The main difference between Dynamic Application Security Testing (DAST) and Static Application Security Testing (SAST) lies in the approach, timing, and the type of vulnerabilities they identify. Both are important in application security, but they test different aspects of an application’s security.

1. Testing Methodology:

• DAST (Dynamic Application Security Testing):
  • Black-box testing: DAST tests the running application (i.e., while it’s in an operational state), typically from the outside, without needing access to the source code.
  • It simulates real-world attacks against a live application to find vulnerabilities that could be exploited in a production environment.
• SAST (Static Application Security Testing):
  • White-box testing: SAST analyzes the source code, binaries, or bytecode of an application before it’s run (i.e., during development).
  • It inspects the underlying codebase to identify coding flaws and security weaknesses at an early stage, such as insecure coding practices or logical errors in the code.

2. When It’s Applied:

• DAST:
  • Applied during runtime—the application needs to be running in an environment (e.g., staging, production, or test).
  • It works well for identifying issues like runtime vulnerabilities, misconfigurations, and security weaknesses that occur when the app is interacting with users or other systems.
• SAST:
  • Applied during development—typically used in the early stages of the Software Development Lifecycle (SDLC).
  • It identifies vulnerabilities in the code before the application is executed, making it suitable for early detection of security flaws that could be baked into the application from the start.

3. Types of Vulnerabilities Detected:

• DAST:
  • Focuses on runtime vulnerabilities, such as:
    • Injection flaws (e.g., SQL injection, command injection)
    • Cross-Site Scripting (XSS)
    • Authentication weaknesses
    • Misconfigurations
    • Session management vulnerabilities
  • It tests how the application behaves when attacked in real-world scenarios.
• SAST:
  • Focuses on code-level vulnerabilities, such as:
    • Buffer overflows
    • Code injection vulnerabilities
    • Insecure coding practices
    • Hardcoded secrets (e.g., passwords or keys in code)
    • Logic flaws and unhandled errors
  • It analyzes the source code for security issues in logic or implementation before they even reach runtime.

4. Tools and Integration:

• DAST:
  • Tools interact with a live application, often through web interfaces or APIs.
  • DAST tools are often used in a CI/CD pipeline but are primarily effective once the application is deployed or running (in staging, QA, or production).
  • Examples of DAST tools: OWASP ZAP, Burp Suite, Acunetix.
• SAST:
  • Tools analyze the codebase directly (source code, bytecode, or binaries) and don’t require the application to be running.
  • SAST tools are typically integrated early in the development lifecycle, allowing security flaws to be detected before the code is deployed.
  • Examples of SAST tools: SonarQube, Checkmarx, Fortify.

5. Depth of Testing:

• DAST:
  • Tests the application as a black-box, looking for vulnerabilities based on how the app behaves during actual execution.
  • It can find vulnerabilities that arise from misconfigurations, data handling, or user input that may not be easily spotted by reviewing the code alone.
  • DAST is limited by what can be observed during runtime and may not identify all vulnerabilities in the underlying code.
• SAST:
  • Tests the underlying code itself and provides a deep analysis of potential issues that might not be observable during runtime.
  • SAST provides greater visibility into the application’s internal architecture, and can find hidden flaws that might not surface through standard testing.
  • However, SAST cannot always detect runtime vulnerabilities (e.g., those triggered by specific inputs or behaviors in production).

6. Cost and Speed:

• DAST:
  • DAST tends to be slower because it tests the live application and may require scanning multiple scenarios.
  • It is typically run on deployed applications, which can increase testing time, especially for complex applications.
• SAST:
  • SAST is faster, as it analyzes code directly and doesn’t require the application to be running.
  • However, it can generate more false positives, requiring manual intervention to review the code.

7. Security Focus:

• DAST:
  • Primarily focuses on external security threats like attacks from external users or hackers.
  • It’s good for identifying injection flaws, authentication issues, and exposure to attacks that can affect users interacting with the system.
• SAST:
  • Primarily focuses on internal security weaknesses within the code that could lead to exploitation.
  • It’s ideal for early detection of flaws that could turn into security risks before they even become part of the deployed application.

Summary of Key Differences:

• DAST is ideal for runtime testing and identifying vulnerabilities in live applications exposed to the internet or end users.
• SAST is more effective during development, allowing teams to catch security flaws in the source code before the application is deployed.

For optimal security, many organizations use both DAST and SAST together as part of a comprehensive application security program, ensuring vulnerabilities are detected both in the code and during runtime.

What is the difference between DAST and IAST?

The main difference between DAST (Dynamic Application Security Testing) and IAST (Interactive Application Security Testing) lies in the approach and the level of integration with the application during testing. While both are focused on identifying vulnerabilities in applications, they differ in how they interact with the application and the level of insight they provide.

Here’s a breakdown of the differences:

1. Testing Approach:

• DAST (Dynamic Application Security Testing):
  • Black-box testing: DAST is typically a black-box testing method, meaning it tests the application from the outside—without access to the internal code or architecture. It interacts with the running application, simulating attacks and looking for vulnerabilities in real-time.
  • It focuses on external threats like injections (e.g., SQL injection, XSS), authentication issues, and other vulnerabilities that can be exploited via the application’s user interface or network interactions.
• IAST (Interactive Application Security Testing):
  • Hybrid approach: IAST is a combination of static and dynamic testing, offering a more interactive and in-depth analysis. It typically operates inside the application, with agents or sensors integrated into the app during runtime, giving it access to both the code and its execution context.
  • IAST tools work by interacting with the application while it’s running, but they also have visibility into the application’s internal components, such as its code, libraries, and server interactions, making it a more interactive testing approach than DAST.

2. Testing Environment:

• DAST:
  • DAST tools test the running application in a live or staging environment. The application needs to be deployed, and the testing is typically conducted through its user interface or via APIs.
  • DAST tools simulate attacks (e.g., SQL injection, cross-site scripting) from an external perspective, treating the application as a “black box” with no knowledge of the code or internal workings.
• IAST:
  • IAST tools work by being instrumented within the application. This means that an agent or sensor is added to the application, allowing the tool to monitor both the application’s execution and source code in real-time while the application is running.
  • This provides real-time feedback on vulnerabilities as they are detected during the app’s normal operation. IAST tools work in the background without interrupting the application’s functionality.

3. Depth of Analysis:

• DAST:
  • DAST analyzes the external behavior of the application during runtime, but it doesn’t have visibility into the source code, so it’s limited to finding issues that can be exploited from the outside, like misconfigurations or input validation flaws.
  • DAST is good for finding vulnerabilities that could be exploited from an external attacker’s perspective, such as flaws in authentication, session management, and user input.
• IAST:
  • IAST provides a deeper analysis by integrating with the application and offering both static and dynamic insights. It has the ability to monitor internal code execution and application behavior while simultaneously analyzing the source code and data flow.
  • IAST can find code-level vulnerabilities that might not be easily spotted during runtime testing (e.g., logical flaws, inefficient code paths, or security flaws in libraries), making it a more comprehensive tool than DAST.

4. Vulnerability Detection:

• DAST:
  • DAST tools primarily detect runtime vulnerabilities like:
    • Injection flaws (SQL injection, command injection)
    • Cross-Site Scripting (XSS)
    • Authentication issues
    • Session management vulnerabilities
    • Exposure of sensitive data
  • Since it only tests external-facing components of the application, it may not detect issues like improper error handling or flaws in the underlying business logic that aren’t directly observable through the app’s interface.
• IAST:
  • IAST tools provide a more comprehensive view of vulnerabilities, including:
    • Business logic flaws
    • Code-level issues (buffer overflows, insecure API calls, etc.)
    • Memory leaks
    • Improper data handling or storage issues
  • Since IAST has visibility into both the running application and its internal code, it can find issues that DAST may miss, especially those tied to application logic or internal coding flaws.

5. Integration and Speed:

• DAST:
  • DAST is generally easy to implement and works well in automated, continuous testing pipelines, but it may be slower as it tests the application as a whole, requiring a fully deployed environment.
  • DAST tools are typically standalone and can be run against any running application without needing access to source code.
• IAST:
  • IAST requires the application to be instrumented with an agent or sensor, which makes it a bit more complex to set up. However, it provides continuous and highly detailed insights during runtime, as it analyzes both the code and the execution context.
  • It is especially useful in DevSecOps environments where continuous testing is needed in combination with real-time feedback.

6. False Positives and Coverage:

• DAST:
  • DAST may produce more false positives since it analyzes external behavior based on simulated attacks and does not have full access to the application’s inner workings.
  • The tool might flag certain responses or behaviors as vulnerabilities without fully understanding the underlying code logic or context.
• IAST:
  • IAST tends to produce fewer false positives because it combines static analysis (knowledge of the source code) with dynamic analysis (real-time testing). This dual approach allows IAST to contextualize the application’s behavior and determine whether an issue is truly a vulnerability.
  • Since IAST understands both code and behavior, it can differentiate between benign behaviors and actual vulnerabilities.

7. Use Cases:

• DAST:
  • Best for identifying runtime vulnerabilities that could be exploited by attackers interacting with a live application.
  • Useful for external penetration testing and compliance testing (e.g., checking for OWASP Top 10 vulnerabilities) in deployed applications.
• IAST:
  • Best for comprehensive, interactive security testing during the development and QA phases.
  • Suitable for identifying deeper issues in the application’s logic, code, and runtime behavior simultaneously.

• DAST is best for testing live applications from an external attacker’s perspective, simulating real-world attacks to identify runtime vulnerabilities.
• IAST is more interactive and offers deeper insights by analyzing both the application’s internal code and its runtime behavior, providing a comprehensive view of code-level and application logic flaws.

For a more robust security strategy, many organizations use both DAST and IAST in tandem: DAST for external testing and IAST for deeper, more integrated analysis.