DAST and IAST are highly effective techniques for app security assessment. However, they use different approaches that come with their benefits and drawbacks. Understanding these advantages and limitations helps companies choose the best approach for their specific needs and improve the reliability and security of their web apps.

Introduction

DAST stands for dynamic app security testing. It is the process of assessing a web app from the front end to identify vulnerabilities through replicated attacks. This approach examines the app from the “outside in” by mimicking malicious user behavior. After conducting these attacks, findings that deviate from expected outcomes highlight potential security weaknesses.

IAST stands for interactive app security testing. It is an app security testing method that evaluates the app while it is running, using automated tools. The core component of an IAST tool is the sensor modules, which are software libraries embedded within the app code. These sensors monitor the app’s behavior during interactive tests. Feedback and results are available immediately within your production environment, quality assurance phase, continuous integration (CI) system, or integrated development environment.

Both DAST and IAST are popular approaches for identifying vulnerabilities in web applications. While each has its advantages and disadvantages, DAST offers several benefits that make it a preferred choice for many organizations.

Consequently, here are some reasons why DAST may be more suitable than IAST. 

Black Box Testing

DAST is a popular black box testing tool that assesses the app entirely without needing access to the source code. This approach allows DAST to identify vulnerabilities that can be exploited by attackers, regardless of the underlying code. In contrast, IAST requires access to the source code, which can be a limitation in some cases.

Absence of Code Instrumentation Needed

DAST does not require any code instrumentation, demonstrating its ability to evaluate apps without modifying the code or altering performance. This is especially useful for complex and larger apps, where code instrumentation can be resource-intensive and time-consuming. Conversely, IAST involves code instrumentation, which can affect app performance and demands significant development effort.

Broader Coverage

DAST can detect a wide range of vulnerabilities, including those related to configuration issues and authentication errors. While IAST plays a vital role in identifying vulnerabilities directly related to code, it is less effective at detecting other types of errors.

Fewer False Positives

DAST tends to produce fewer false positives because it tests the app in a real-world environment. On the other hand, IAST may generate false positives due to its dependence on code analysis.

Simpler Integration

DAST is easy to integrate into existing development workflows because it does not require modifications to the development process or the codebase. Similarly, IAST can be integrated without major changes to the toolchain or development procedures.

Conclusion

As discussed above, both DAST and IAST have their advantages and disadvantages. DAST offers numerous benefits that make it a preferred choice for many organizations. Its black box testing method, minimal need for code instrumentation, wider coverage, reduced false positives, and ease of integration make it an efficient way to identify vulnerabilities in web applications. Relying on DAST enables companies to improve the reliability and security of their apps, reducing the risk of data breaches and cyberattacks.

Frequently Asked Questions (FAQs)

What is meant by DAST?

DAST stands for dynamic app security testing. It is the process of assessing a web app from the front end to identify vulnerabilities through replicated attacks. This approach examines the app from the “outside in” by mimicking malicious user behavior. After conducting these attacks, findings that deviate from expected outcomes highlight potential security weaknesses.

What is meant by IAST?

IAST stands for interactive app security testing. It is an app security testing method that evaluates the app while it is running, using automated tools. The core component of an IAST tool is the sensor modules, which are software libraries embedded within the app code. These sensors monitor the app’s behavior during interactive tests. Feedback and results are available immediately within your production environment, quality assurance phase, continuous integration (CI) system, or integrated development environment.

What are the five factors that make DAST a suitable option?

• Black Box Testing
• Absence of Code Instrumentation Needed
• Broader Coverage
• Fewer False Positives
• Simpler Integration