August 13, 2020

SAST vs DAST: What’s the Difference?

Static Analysis

SAST vs DAST — what's the difference? Both tools help to ensure that your software is secure and safeguarded against vulnerabilities. This makes the DevSecOps process easier. Here, we explain the difference between SAST vs DAST to help you better understand when you should use each one.

Read along or jump ahead to the section that interests you the most:

➡️ Start using Klocwork sast

SAST vs DAST: Overview of the Key Differences

Both tools are used to identify software security vulnerabilities. However, they work in very different ways.

Here are the most notable differences between SAST vs DAST.

When to Use SAST vs DAST

Here's what you need to know:

White Box Security Testing
This type of software security technique is often referred to as white-box security testing (or the “developer approach”), which means you have access to the underlying framework, design, and implementation of the software. In addition, this type of tool tests the software from the inside out.

Source Code Is Required
This type of tool doesn’t require you to run your software in order to analyze it for vulnerabilities. Instead, it analyzes your source code, byte code, and binaries, without executing anything, generally providing the fastest possible feedback and requiring the least amount of work.

Vulnerabilities Found Earlier in Development and are Less Expensive to Fix
This type of tool is able to scan your code as it is being written. This helps to ensure that security vulnerabilities and coding errors are identified as soon as possible. This also makes it easier, faster, and cheaper to fix those issues.

Unable to Identify Timing- and Environment-Related Issues
As this type of tool scans static code, it is unable to identify timing- and environment-related vulnerabilities.

Generally Supports all Kinds of Software
You can use this type of tool to analyze most types of software, including embedded software, enterprise applications, mobile applications, web applications, and web services.

When to Use DAST vs SAST

Here's what you need to know:

Black Box Security Testing
Conversely, DAST is often referred to as black-box security testing (or the “hacker approach”), you don’t have access to the underlying framework, design, and implementation of the software and so internal detail is obscured. A DAST tool tests the software from the outside in.

A Running Application Is Required
A DAST tool requires you to run your software in order to analyze it for vulnerabilities.

Vulnerabilities Found Later in Development and are More Expensive to Fix
A DAST tool only analyzes software that can be compiled and run, which means that it can only identify vulnerabilities late in development. This makes it more difficult, time-consuming, and — therefore — more costly to fix errors.

Can Identify Run-Time and Environment-Related Issues
As a DAST tool uses Dynamic Analysis to inspect your software, it is able to identify timing- and environment-related issues.

▶️ Related On-Demand Webinar: Learn how to ensure your security development and testing is efficient.


Here are the main advantages of this type of tool:

  • Finds issues by looking for known vulnerability patterns for internationally recognized coding standards for security, as well as safety, and quality.
  • Early defect detection and remediation, which lead to lower costs of remediation.
  • Shift-Left approach — analysis available everywhere, including developer desktop and CI/CD pipelines.
  • Easy to automate, scalable, and automatically provides the highest levels of code coverage.
  • Feedback is fast and provides the exact location of vulnerabilities and their cause.


Here are the main advantages of this type of tool:

  • Analyzes the whole application as it runs, within the full system environment.
  • “Look inside” the application and dynamically analyze execution logic and live data.
  • Language and Source Code independent.
  • Checks memory consumption and resource use.
  • Attempts to break encryption algorithms from outside.
  • Verifies permissions to ensure the isolation of privilege levels.
  • Checks for cross-site scripting, SQL injection, and cookie manipulation.
  • Tests for vulnerabilities in third-party interfaces.
  • Understands arguments and function calls.
  • Record application execution for post-mortem test failure analysis.
  • Catch hard application failures.
  • Unattended script-based dynamic analysis.

SAST vs DAST: Use Both for Your Security Program

As part of an effective security program, both SAST and DAST should be used together, as they are able to identify vulnerabilities that the other may not.

However, one is not inherently better than the other. Both are needed in order to conduct comprehensive application security testing.

For more information on SAST vs DAST, watch our on-demand webinar, Efficient Security Development and Testing Using Dynamic and Static Code Analysis.

▶️ Watch the SAST vs DAST On-Demand Webinar

Alternatively, you can register for a Klocwork free trial to see how it can help you ensure the security and reliability of your code.

➡️ Klocwork free trial