Ensuring Robust Application Security: Exploring SAST, DAST, and IAST for Comprehensive Protection

Ranjan Singh CyberSecurity
3 min readMay 22, 2023

Application security (AppSec) is a practice of protecting software applications from security threats and vulnerabilities. It encompasses various techniques and measures to ensure that applications are secure and resilient against attacks. There are three key aspects of application security: Static Application Security Testing (SAST), Dynamic Application Security Testing (DAST), and Interactive Application Security Testing (IAST). Let’s explore each of these in detail, along with examples.

  1. Static Application Security Testing (SAST): Static Application Security Testing involves analyzing the application’s source code, byte code, or binary code without executing it. SAST tools examine the application’s codebase for potential vulnerabilities, coding errors, and security flaws. This type of testing is typically performed during the development phase.

Example: Let’s consider a web application that allows users to submit comments. A SAST tool can analyze the source code of the application to detect security vulnerabilities such as SQL injection, cross-site scripting (XSS), and insecure direct object references. It can identify code patterns that may lead to these vulnerabilities, allowing developers to fix them before deploying the application. Some tools are:

  • SonarQube: An open-source platform that performs SAST on a wide range of programming languages.
  • Veracode: A commercial SAST tool that provides static analysis and vulnerability scanning capabilities.
  • Checkmarx: A commercial SAST tool that helps identify and fix security vulnerabilities in source code.

2. Dynamic Application Security Testing (DAST): Dynamic Application Security Testing involves analyzing an application while it is running and interacting with it to identify vulnerabilities. DAST tools simulate real-world attacks on the application and evaluate its security posture by sending requests, injecting malicious data, and observing the responses. This type of testing is typically performed in a test or staging environment or even in production with proper precautions.

Example: Let’s say there’s a mobile banking application. A DAST tool can simulate an attacker by sending requests to the application, attempting to exploit vulnerabilities like insecure authentication, session management issues, or insecure API endpoints. By analyzing the responses and behavior of the application, the tool can identify security weaknesses that need to be addressed. some tools are:

  • OWASP ZAP: An open-source DAST tool that helps identify vulnerabilities by simulating attacks.
  • Burp Suite: A commercial tool with DAST capabilities, commonly used for web application security testing.
  • Acunetix: A commercial DAST tool that scans web applications for vulnerabilities and provides detailed reports.

3. Interactive Application Security Testing (IAST): Interactive Application Security Testing combines the benefits of SAST and DAST. It analyzes the application’s code and runtime behavior simultaneously to provide real-time security analysis. IAST tools use instrumentation or agent-based approaches to monitor the application during testing, capturing data about code execution and identifying vulnerabilities.

Example: Consider a large enterprise-level web application. An IAST tool can be deployed within the application’s runtime environment. As the application executes, the tool can track the code flow and identify potential security issues such as insecure data handling, injection attacks, or improper error handling. By combining static and dynamic analysis, IAST offers more accurate and actionable results. some tools are:

  • Contrast Security: A commercial IAST tool that combines runtime analysis with static analysis to identify vulnerabilities in real-time.
  • Hdiv Security: A commercial IAST tool that monitors applications at runtime and provides actionable security insights.
  • Seeker by Synopsys: A commercial IAST tool that analyzes code execution and detects vulnerabilities during runtime.

SAST Vs DAST Vs IAST

It’s important to note that there are many other tools available for application security testing, and the selection of tools depends on factors such as the programming language, application architecture, budget, and specific security requirements of the organization. Additionally, organizations may also integrate these tools into their continuous integration and delivery pipelines to ensure security throughout the software development lifecycle.

Overall, these three approaches to application security — SAST, DAST, and IAST — complement each other by addressing different aspects of security. SAST helps identify coding vulnerabilities, DAST tests for vulnerabilities in a running application, and IAST provides real-time analysis by combining both static and dynamic techniques. Organizations often employ a combination of these methods to ensure comprehensive application security and reduce the risk of security breaches and data compromises.

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Ranjan Singh CyberSecurity

Application Security | DevSecOps | Cloud Security | Offensive Security | Cyber Defense | Security Operations | VAPT | WAF | DLP | Cyber Security | IITian