What Is SAST: Static Application Security Testing

In this tutorial we will learn what is Static Application Security Testing (SAST), how does it work, its benefits, its implementation, etc:

Static Application Security Testing is a security tool that analyzes source code to detect any security vulnerabilities in your enterprise applications. It is white box testing, and it scans an application before the source code gets compiled.

SAST is a security tool that handles a very important role within a Software Development Life Cycle (SDLC) environment which is used to identify security bugs in an application before it is deployed to the production environment.

It helps organizations remediate vulnerabilities very early in the SDLC. It is at this stage that developers do code analysis to detect which line the vulnerability lies in so that they can fix the security issues and re-test before it is deployed to production.

When SAST is integrated into a CI/CD pipeline, it helps transform DevOps into DevSecOps which helps to secure your agile environment.

What Is Static Application Security Testing

What is SAST

According to the Micro Focus application security risk report about web applications, it was observed that 94% of 11,000 web applications that were analyzed have security vulnerabilities and it was also confirmed that code quality and API issues have increased over the years.

If some of these vulnerabilities find their way to production, they could provide a backdoor for attackers to carry out an exploit and could lead to a data breach which could cause financial loss and can damage the reputation of an organization.

How Does SAST Work

Static Application Security Testing makes use of a code analysis process to check the code for any coding design flaws which could cause an application vulnerability. During the analysis, it will identify different security issues like SQL injections, un-sanitized input, error handling, and many more.

It is an application security tool that can check for different security issues and also check for other functional issues that bugs or quality of code could cause and at the same time enforce coding standards for the development team.

It is usually good to set up Static Application Security Testing right from the beginning of a project and not when the code lines have risen to a very high figure which could now become a challenge for the development and security team to start remediating the vulnerabilities within.

SAST is often compared to DAST but the two have several differences.

Suggested Reading =>> Compare SAST, DAST, IAST, And RASP

Static Application Security Testing makes use of white-box testing to analyze the source code to remove vulnerabilities while DAST on the other way does not have access to the source code but only uses the process of black-box testing to scan a compiled application to detect any vulnerabilities that exist within.

How Do You Implement SAST

There are distinct steps you can take to implement SAST into your organization’s development process because most of these organizations build their applications with different programming languages and frameworks.

#1) Getting the right tool: The first thing you need to do is to pick the right SAST tool that can properly carry out the code analyses in the languages that your applications have been written. This is very important because, for a SAST tool to do well, it must support the application framework used.

#2) Set-up testing and deployment environment: There is a need to purchase all necessary resources, like servers and network tools needed to deploy the SAST tool. After all these resources are put in place for a proper testing environment, the installation of the tool can proceed.

Once the SAST has been installed, then the next step will be to scan all the applications in the pipeline. One major concern is scanning the applications with the highest risk first before scanning the ones with lower risk.

#3) Scanning Interval: This tool must be run regularly. This could be daily, weekly, and monthly. Anytime you have a code that is checked in or a code release then carry out your scan.

#4) SAST tool customization. The tool can be customized to suit your testing requirement. You can set up your dashboard to display scan results you can track, and you can also generate reports both online and offline. You can also configure the SAST with some new rules in a manner to detect some other security vulnerabilities.

The rate at which Static Application Security Testing picking false positives is high, so there is a way to configure the SAST to reduce all the false positives picked before the result is sent to the development team for remediation purposes. When the result is sent back to the developers in an organized way, it will help the developers to quickly remediate the issues and create a new release.

#5) Essential training. Every team member should be trained on the use of SAST in the right way for it to bring out the best result. Necessary guidelines for the use of the SAST should be available and it should be properly followed. The tool should be part of the secure code review session where there is always a deliberation on what could go wrong with the coding style used.

We should encourage Static Application Security Testing within the development team and management team as a very important security tool that every organization must have in their possession.

Benefits Of SAST In DevOps

These are as follows:

#1) Discover Vulnerabilities: One major purpose is the detection of vulnerabilities in the source code. They help developers and security teams to detect some security bugs that other security tools may not detect.

#2) Early Detection: When a security issue is not detected and fixed on time may cause serious repercussion. That is where this tool comes into play. This tool helps the development and security team to diagnose an issue very early and such an issue is fixed before releasing the application for general consumption.

It helps reduce the amount that would have been spent on remediating the issue when the application is already deployed. It does not need to interact with a running application, it only needs access to the source code and it will discover any security issues within.

#3) Simplify Root-Cause Analysis: No developer wants to go through the rigorous way of checking the source code to know where the issues lie in the line of code. With this tool, you get informed where the problem lies in the line of code and what needs to be done to remediate the issue.

This simplifies the task of the developer in finding what to fix in the code and they now spend most of their useful time in developing new applications and new features. The feedback system that it provides is very simple and guides you on what to do even though you are not an expert in the security domain.

Vulnerabilities Detected By SAST Tools

The kind of vulnerabilities this tool detects is depended on the type of programming language, libraries, and frameworks used.

For example, an application is written with JavaScript that is susceptible to cross-site scripting vulnerabilities. But we now have some application frameworks that have security features that are already embedded, but this is not enough.

Below are some common vulnerabilities that you can find seriously affecting all applications and which SAST can help you fix:

#1) SQL Injections

This is a kind of attack that can be carried out on an application that is data-driven by a mere injection of SQL into the database to retrieve confidential information. With Static Application Security Testing, these vulnerabilities in an application can quickly be detected and remediated.

Below is an example of an SQL Injection:

SQL Injections

#2) Input Validation

This is a vulnerability that is still very common today. This occurs when an attacker intentionally inserted malicious inputs into an application and watches the effect it has on the application. The SAST is a tool that is fully designed and ready to detect anywhere in the coding section that would allow this vulnerability.

The below is an example of input validation:

input validation

[image source]

#3) Stack Buffer Overflows

This occurs because of a program trying to write more data into the buffer of an application more than what it can accommodate. Stack buffer overflow can cause data corruption and sometimes cause an application to shut down or even crashes.

Below is an example of stack overflow:

Stack Buffer Overflows

[image source]

#4) Cross-Site Scripting

Cross-site scripting occurs when an attacker tries to deceive a genuine user of an application by sending malicious code as a browser-side script to this user. Currently, we have so many applications online that allow this kind of attack to be carried out on it simply because both the input and output are not properly validated and encoded.

Below is an example of cross-site scripting:

Cross-Site Scripting

[image source]

Static Application Security Testing: Pros And Cons


  • Early SDLC: It is built for source code and can scan your code even while still writing it. We have IDE readily available that the Static Application Security Testing application can plug into. It checks your code against best practices. It can be applied when you are writing your code. The IDE plugins for SAST are readily available online it is a matter of a click away.
  • Line of Problem: It is a wonderful security tool that will not only detect vulnerabilities for you but also show you where the exact issue is so it can be quickly remediated.
  • Defined or Pre-defined Rules: Unlike DAST tool you decide what you want to test but with SAST it will apply rules to the source code and these rules can be set manually or can be automated using algorithms used for the predefined rules in the SAST.
  • Non-execution: It is a security tool that only needs the static source code to work and does not need the code to be run. The reason SAST scan is much faster than DAST is that runs on a compiled code.
  • Easy automation: Static Application Security Testing does not need many configurations like DAST as the automation is purely simple and easy.


  • False positives: One of the major disadvantages of SAST access to the source code is the high level at which it captures false positives. When SAST is used to scan an application code, it usually picks some line of codes that has issues even though it will later be found that it is a false positive claim. Some of these raised security issues may not be a problem and may not even pose a threat to the organization.
  • Misplaced Test: One reason Static Application Security Testing usually displays false positives is that sometimes it scans the wrong place meanwhile the fix is in another place. For instance, un-sanitized user input could have been fixed at the back-end and because the same issue has not been fixed from the front-end, the tool could capture it as an issue simply because all the application codes are not in the same repository and this could result into false positives.
  • Language Dependent: SAST is a security tool that depends on the type of programming language used. For instance, if you need to procure a SAST tool, you will need to get the type that supports the programming language used to develop your application.
  • Getting over one SAST: Sometimes it is advisable to have more than one SAST tool as a particular one may not detect all the vulnerabilities in an application. While one may support multi-language, another one may have high performance in wide testing.
  • Difficult Initial Setup: Some developers complain that the initial setup of SAST in an agile environment does not come easy. The more reason you need to carefully consider the type of SAST you want to use, it should be a tool that will give you fewer challenges when setting it up.

Using SAST With Other Security Tools

Static Application Security Testing interacts with the source code by scanning the codes for vulnerabilities. This is in total opposite to DAST which does not have access to the source code but only interacts with inputs and outputs when the application is running. Both security tools complement each other, a vulnerability that one does not seem may be detected by the other tool.

The speed is another factor when using SAST with other security tools. For instance, DAST requires more time to complete scanning of a running application, while access to the source code makes SAST scanning to be faster, but both will always give you the best approach to remediate the issue and improve your application security.

Always plan to use a SAST tool from the commencement of the development and you can integrate other tools like IAST and RASP also very early during the SDLC while using the DAST tool at a later time when the code has been compiled and deployed to the staging environment for alpha and beta testing.

Always know that any vulnerabilities that cannot be found very early by Static Application Security Testing could later be found by other security tools.

Frequently Asked Questions

Q #1) What SAST means?

Answer: Static Application Security Testing (SAST) is a security tool designed to analyze the source code of an application in other to detect any vulnerabilities within and guide the remediation process.

Q #2) What are SAST and DAST?

Answer: SAST is white box testing by accessing the application source code without running. While DAST is a black box testing that does not have access to the source code but only examines an application as it’s running to find vulnerabilities that an attacker could exploit.

Q #3) What are SAST and DAST tools?

Answer: Both are security tools that help detect security issues within an application code before such application is deployed to the production environment.

Q #4) Is Static Application Security Testing more expensive to fix vulnerabilities?

Answer: It is not expensive to fix vulnerability the reason is that it is a security tool used very early in the SDLC to detect and fix vulnerability at a lower cost which is in contrast to the DAST tool that fixes security bugs after code compilation and fixing this vulnerability could later be more expensive.

Q #5) How do you perform a SAST test?

Answer: SAST performs security testing by scanning the static source code in other to detect vulnerabilities that could make the application susceptible to exploitation from attackers. It scans this code before it is compiled for the production environment.

Q #6) What are examples of SAST tools?

Answer: They are:

  • Gitlab
  • Github
  • Sonarcube
  • Sonarcloud
  • Checkmarx
  • Micro Focus
  • HCL AppScan


Static Application Security Testing tool supports the shift-left testing principle where the test is done very early during the SDLC. So every organization must start transforming their DevOps environment to DevSecOps because you cannot keep developing applications for the public without going through proper security checks.

Any application that has not gone through a rigorous security test should never be allowed to the production environment.

Also, Read =>> Best Application Security Testing tool 

It is also advisable to combine a Static Application Security Testing tool with other security tools. This will bring the best result and most of the security vulnerabilities will be removed. Every organization should start spending big in terms of security because security is not optional in an agile environment.