Application Security Testing (AST) SAST, DAST and IAST

Security testing is growing faster than any other security market in IT Systems, as AST (Application Security Testing) solutions adapt to new development methodologies and increased application complexity.

Experts determine that about 90% of security incidents are the result of attackers exploiting known software errors.

In this sense, TSA has become a pillar in the development of secure applications.

Application testing aims to rule out the possibility of faulty code

As a result, it happened that the applications ran smoothly after development.

These tests detect any errors from the beginning.

They also help developers, to prevent errors from reaching the final version of the software.

Eliminate errors in the software development phase. As a result, they reduce information security risks.

It is necessary to maintain the level of security, continuously testing the running applications.

This prevents your business from suffering financial and reputational damage.

That’s why when we talk about developing and designing secure applications.

There are a number of technologies on the market that help detect faults, in the source code.

Static Application Security Testing (SAST)

The use of Static Application Security Testing (SAST) allows you to detect defects in the early stages of development.

These tools known as code analyzers, perform a direct analysis of the application’s source code or “white box test”.

The analysis runs in a static view of the code, which means that the code is not running at the time of review.

Nowadays, SAST security tools are being widely adopted in the software industry.

Benefits of SAST include:

SAST tools discover highly complex vulnerabilities during the early stages of software development, helping to resolve them quickly.

  • It has extensive support for different programming languages.
  • Integrates into existing environments. Also, at different points in software development.
  • Because it sets the details of a problem, including the line of code, it simplifies repair.
  • It takes little time to examine the code and compares favorably with manual audits.

The drawbacks of SAST are as follows:

  • The application cannot be tested in the actual environment.
  • Vulnerabilities in application logic or unsafe configuration are not discoverable.
  • It tends to model code behavior inaccurately.
  • 53% of the problems detected do not exist.
  • Developers have to deal with many false positives and false negatives.
  • The result is a static report that quickly becomes obsolete. Implementing technology at scale can be challenging, the process can be slow, and testing is not applicable to production-stage systems.
  • Not all companies or individuals are willing to provide data for binary code and source code analysis.

SAST tools are very valuable, but as we can see, they have very marked limitations. Developers must use this technology in conjunction with others to achieve timely flaw detection during the development process.

Dynamic Application Security Testing (DAST)

Dynamic Application Security Testing (DAST) provides an external perspective of the application before it gets up and running; These tests, also known as “black-box testing,” test the exposed interfaces of a running application for vulnerabilities and failures, usually in web applications.

The principle of testing revolves around the introduction to test code path failures in an application, for example, it can send malicious data to the software in order to identify common security vulnerabilities, such as SQL injection and inter-site scripts.

These tools are used during the testing and quality control phase during the software development lifecycle.

DASRs examine only system responses to a battery of tests designed to highlight vulnerabilities. They are, in short, a vulnerability scanner.

Benefits of DAST include:

  • Analysis allows developers to detect runtime issues, which is not something SAST is capable of. These can be authentication and network configuration failures or issues that arise only after login.
  • There are fewer false positives.
  • Supports custom programming languages and frameworks available on the market.
  • It presents a less expensive and complex alternative to SAST.

The drawbacks of DAST are as follows:

  • DAST tools do not provide information about the underlying causes of vulnerabilities and also have difficulty maintaining coding standards.
  • The analysis is not suitable for the early stages of development.
  • It can only be checked in a running application.
  • It will not perfectly simulate potential attacks.
  • Exploits are executed with an internal knowledge base on the application.


Tools connect to the development process at different stages.

SAST will not encounter encoding errors during code execution without the DAST flag.

Until you find an error in the line of code.

The choice between adopting static analysis (SAST) or dynamic (DAST) tools depends primarily on what you are trying to achieve.

SAST provides developers with educational feedback, while DAST offers security teams improvements quickly.

Interactive Application Security Testing (IAST)

The IAST, using software instrumentation to evaluate how an application works and detect vulnerabilities, these tests have an “agent-like” – i.e., a user – approach, meaning agents and sensors run to continuously analyze application performance during automated testing, manual testing, or a combination of both.

The process is done in real-time. Also, both in the integrated development environment (IDE).

Also while in production, in the continuous integration (CI) or quality control environment.

IAST tests have access to full code, data flows and control flow, system configuration data and web components, as well as back-end connection data.

The advantages of applying IAST are:

  • The accuracy of an IAST greatly improves that of SAST and DAST, because it benefits from static and run-time views.
  • An IAST is more flexible than SAST and DAST because it can be used by multiple computers throughout SDLC.
  • Vulnerability details provided by an IAST provide static information (source file and line number) and dynamic information (URL and parameters)
  • IAST analysis provides complete lines of code that contain data, so security teams can pay immediate attention to a particular failure, which means that problem resolution occurs more quickly.
  • The IAST test can be integrated into CI/CD pipelines with ease.

The drawbacks of IAST are as follows:

  • IAST tools can slow down application operation. Agents essentially serve as additional instrumentation, which makes the code not work as well.
  • Some problems may not yet have been discovered, as this is a relatively new technology.

Which Application Security Testing technique to choose?

AST development uses different techniques to discover security vulnerabilities at different stages of an application’s lifecycle (design, development, deployment, upgrade, maintenance, etc.)

In this regard, each of these technologies has its advantages and disadvantages a combination of both methods is recommended.

For in this sense, it covers all stages of the process in a flexible way.

One of the most important attributes of safety testing is ongoing coverage and monitoring. Manual audits and safety tests can only cover a certain area.

Therefore, to assess the security of an application, an automatic scanner must be able to accurately interpret that application.

Security Testing Software (IT)

In summary, as explained above, there are two main approaches to application security testing.

A black box security testing methodology, (DAST) in which an application is tested from the outside.

The other end of the spectrum is the SAST safety test, which is a white box test methodology, that examines the application from within, looking in its source code for conditions that indicate that a security vulnerability might exist.

The fusion of these two approaches is called IAST testing or gray-box testing.

Which are available, for example, in software such as Acunetix, thanks to their AcuSensor technology, one of the first application security solutions to use this methodology.

Acunetix comes equipped with a suite of application security tools designed to continuously automate and monitor processes to help you identify security vulnerabilities in the early stages of the software development lifecycle.

Acunetix AcuSensor

AcuSensor is activated by installing a sensor in the backend of the application.

The sensor then transmits real-time information about the executed code to the scanner. This also includes hidden entries, hidden files, and configuration information that the scanner could not obtain using a black-box methodology.

Acunetix AcuSensor can detect the following types of security vulnerability in IT systems: SQL Injection, Code Injection, CRLF Injection, Directory Break, Arbitrary File Creation/Deletion, Email Header Injection, File Upload, File Inclusion, Manipulation File, PHP Code Injection, and PHP Super Globals Overwrite.

Finally, if you need expert advice to find the best software solution that ensures the security of your company’s IT and security systems, don’t hesitate to contact us to provide you with the best possible support.

In GB Advisors, we have everything you need to help you understand all aspects of application security. We offer comprehensive solutions to protect your networks from all kinds of vulnerabilities.

Contact us now! We have high-tech tools and free advice with incredible discounts for you.

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