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SAST, DAST, and IAST: Understand the Difference Between These Application

Have you ever heard of AST – Application Security Test? If you’ve never heard of it, throughout this article we’ll explain what it’s all about and why tests like these are so important for application security.

The best known are SAST, DAST, and IAST. Now, if you are from a team that has heard of it, and even knows a little about it, this article will also be important to understand the best option to use to protect your code and the difference and advantages between each of them.

What is Application Security Test?

Application Security Test is used to help rule out the possibility that the code has an error or defect, and to ensure that the software or application runs smoothly after its development.

Many security incidents are caused by attackers exploiting software bugs, so application developers need to always be on the lookout for bugs from the very beginning of the project so that the information security risks that many companies face today are reduced.

For the systems’ security level to be maintained, developers need to test the code from time to time, so that any sign of a bug is resolved in a timely manner, avoiding financial losses or a bad reputation for the company, after all, a bug can generate bad news.

Application performance, in addition to generating bad reviews from users, compromises the company’s brand in the market.

Don’t worry, there are some tools that help the developer detect security flaws in the code even before they are incorporated into the final software release.

There are three types of tests that are the most popular, and they are DAST, SAST, and IAST.

Explaining better about SAST, DAST, and IAST and what is the difference between them

The choice between adopting static or dynamic analysis tools depends mainly on what the developer wants, as each test has a different purpose and, for that reason, must be carried out for specific actions and moments.

Static security testing (SAST): This type of testing works directly with a tool’s code. The components of a tool are verified without the product being executed and it can happen through an automated tool or through manual tests, the main objective of this test is to identify programming errors, such as bad practices, syntax errors, and failures of safety.

Static analysis helps IT managers to identify all lines of code that were poorly written during software creation. All execution, processing, and displaying paths of values ​​are examined. As a result, more common errors are discovered more quickly.

Dynamic Security Testing (DAST):  Dynamic testing can be used to complement static analysis. This type of test works mainly with the information that is inserted in the data input and output routines.

In addition, items such as response time, application performance, the software’s ability to adapt to different environments, and functional behavior are checked.

Many companies adopt dynamic analysis because it allows more subtle problems to be identified. No matter the degree of complexity, the chances of a bug going through static analysis and a dynamic analysis without being tracked are considerably low.

Interactive Security Testing (IAST): IAST uses software instrumentation to assess an application’s performance and detect vulnerabilities. Agents and sensors run to continuously analyze the health of the application during automated testing, manual testing, or a combination of the two.

The process and feedback are done in real-time in your integrated development environment (IDE), continuous integration (CI) environment or quality assurance, or during production. Sensors have access to the entire code, data flow, control flow, system configuration data, web components, and backend connection data.

What are the advantages and disadvantages of using SAST? 

SAST tools are a very valuable technology, but they do not replace other methods. Developers used a combination of techniques throughout the process to conduct assessments and detect flaws before going into production.

Advantages: SAST tools discover highly complex vulnerabilities during the early stages of development; The specifications of a problem are established, including the line of code, making it simple to fix the failure;

SAST can be integrated into the existing environment at different points in the software or application development cycle.

Easy to examine code compared to manual audits.

Disadvantages: Deploying technology at scale can be a challenge for companies;

It models code behavior not very accurately, so developers need to be aware of some false positives and false negatives.

Dynamically typed languages ​​present challenges:

The SAST tool needs to semantically understand many moving parts of code that can be written in different programming languages;

It cannot test the application in the real environment, so vulnerabilities in application logic or insecure configuration are not detectable.

What are the advantages and disadvantages of using DAST?

It’s worth remembering that the SAST tool provides educational feedback to developers, while DAST provides security teams with improvements delivered quickly.

In some cases, both can be run together as they are tools that connect to the development process in different places.

Advantages: Through analysis, developers identify runtime problems (authentication failures, network configuration, or problems that arise after login);

  • False positive cases are less frequent.
  • Support for out-of-the-box custom programming languages ​​and frameworks.
  • Alternative with better cost-benefit and less complex compared to SAST.


Disadvantages: DAST does not provide information on the underlying causes of vulnerabilities and may present some difficulties in maintaining coding standards.

Because the analysis can only be done on a running application, the tool is considered unsuitable for earlier stages of development.


What are the advantages and disadvantages of using IAST?

The main difference between IAST SAST and DAST is that it operates within the application. Access to a wider range of data makes IAST coverage greater, compared to source code or HTTP scanning, and allows for more accurate output.

Advantages:  Problems are detected earlier, so IAST minimizes costs and delays due to an approach called Shift-left, which means it is carried out during the early stages of the project lifecycle;

  • IAST Analysis provides complete lines of code containing data, so security teams can pay immediate attention to a specific flaw.
  • Accurately identifies the source of weaknesses due to the range of information that the tool has access to.
  • IAST can be integrated into CI/CD (continuous integration and deployment) pipelines with ease, unlike other tests.

Disadvantages: The only downside of IAST so far is that it can slow down the operation of the application, this is because the agents essentially serve as additional instrumentation, causing the code to not perform well at times;

What is the importance of security testing in applications?

An application security test is important for your business and the entire company.

These are the tests that will point out if there are no flaws in the application code, if it is safe and if everything is working correctly.

Application security test ensure that the information system is protected, as well as the data, in addition to keeping its functionality up to date and free of vulnerabilities.

The entire development testing process involves analyzing the application in search of technical flaws, weaknesses, and vulnerabilities, to the design part, as the objective is to identify risks and correct them even before its deployment and final release.

An application that is not tested and validated from the beginning of its development may have existing vulnerabilities in its code and may fail to protect the company and user data from malicious attacks.

For an application to be developed securely, it is essential to respect the development lifecycle, and security is one of the most important elements that must be considered throughout the cyclical process of application development, especially when the application is developed to handle critical processes and information, such as an application that focuses on selling shares of a particular company on the stock exchange, or a simple e-commerce application where all user data is recorded.

The security of applications and even software is increasingly one of the most sensitive aspects of cybersecurity for companies. For risks to be mitigated, companies need to identify vulnerabilities quickly and efficiently.


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