Application security testing is crucial to make sure your application is free of flaws and dangers, to minimise the attack surface, and to guard against online threats.
Applications are frequently utilised in almost every industry to make it simpler and more convenient for customers to use goods and services, consultations, entertainment, etc.
No matter how closely programmers adhere to the most recent secure coding standards or how well they intend, some production code will almost always include at least one security flaw.
There are two effective methods for doing application security testing: static application security testing (SAST) and dynamic application security testing (DAST).
This article explores when to use SAST and DAST and compares both to help you understand which is preferable in certain circumstances.
What is DAST?
Dynamic Application Security Testing, referred to as DAST, is a software testing method that uses a “black-box” approach which assumes that the testers are unaware of the source code or internal workings of the application or don’t have access to it.
To find potential weaknesses, DAST tests simulate actual cyberattacks on the application, like SQL injection and cross-site scripting (XSS).
The goal of DAST is to identify and report on security issues that could be exploited by an attacker, so that they can be fixed before the application is deployed.
DAST is often used in conjunction with other testing methods such as SAST (Static Application Security Testing) and penetration testing to provide a comprehensive view of an application’s security posture.
When to use DAST?
DAST should be used when an application is close to or already in production. It is typically used to test web applications, but can also be used to test APIs, mobile apps, and other types of applications that have external facing interfaces.
DAST can help identify security vulnerabilities that may have been missed during the development process, such as misconfigurations or errors in the application’s code.
It’s also useful when there are changes made to the application and the development team want to ensure that no new vulnerabilities have been introduced.
Additionally, DAST is useful for compliance with industry standards and regulations, such as PCI DSS, that require regular testing of applications for security vulnerabilities.
Benefits of using DAST
There are several benefits of using DAST as part of a comprehensive application security testing strategy:
1. Identifies vulnerabilities in the application’s runtime environment
DAST examines an application while it is operating, simulating real-world attacks to find vulnerabilities that may not have been found during the development process.
2. Helps with compliance
DAST can help organizations meet industry standards and regulations that require regular testing of applications for security vulnerabilities, such as PCI DSS.
3. Identifies misconfigurations
DAST can identify misconfigurations in the application’s runtime environment that could lead to security vulnerabilities.
4. Provides a comprehensive view of the application’s security posture
DAST can be used in conjunction with other testing methods such as SAST and penetration testing to provide a more comprehensive view of an application’s security posture.
5. Identifies new vulnerabilities in the application after changes are made
DAST can be used to test an application after changes have been made to ensure that no new vulnerabilities have been introduced. It helps organizations prioritize the security vulnerabilities and fix the critical vulnerabilities first.
6. Provides actionable information to development teams
DAST can provide detailed information about the vulnerabilities it finds, including the specific location of the vulnerability in the code and the steps needed to fix it.
7. Better security in all environments
You can accomplish your application’s highest level of security and integrity since DAST is applied on it from the outside rather than on its underlying code.
What is SAST?
SAST stands for Static Application Security Testing which is a white-box testing methodology. It is a method of analysing an application’s source code, binary code or bytecode for security vulnerabilities without actually executing the application.
SAST tools typically parse the source code or binary code and use a set of rules or a database of known vulnerabilities to identify potential security issues.
The goal of SAST is to identify and report on security issues that could be exploited by an attacker, so that they can be fixed before the application is deployed.
SAST can be used during the development process, as it can identify vulnerabilities early and allow them to be fixed before the application is deployed.
It can also be used to test third-party libraries and frameworks that are used in the application.
When to use SAST?
SAST should be used during the development process to identify and fix vulnerabilities early on, before the application is deployed.
It can also be used to test third-party libraries and frameworks that are used in the application.
Some of the key scenarios when to use SAST are:
1. During the development phase
SAST can be integrated into the development process, allowing developers to identify and fix vulnerabilities as they write code.
2. Before releasing the application
SAST can be used to test the application’s codebase before it is released to ensure that it is free of known security vulnerabilities.
3. When using third-party libraries and frameworks
SAST can be used to test third-party libraries and frameworks that are used in the application, to identify any vulnerabilities that may be introduced by these components.
4. To identify compliance issues
SAST can be used to identify vulnerabilities that may be in violation of industry standards and regulations.
5. When there are changes made to the codebase
SAST can be used to test the codebase after changes have been made to ensure that no new vulnerabilities have been introduced.
Benefits of using SAST
SAST (Static Application Security Testing) provides several benefits, including:
1. Early detection of vulnerabilities
SAST can detect vulnerabilities in the early stages of the software development lifecycle, which allows for faster and more cost-effective remediation.
2. Automation
SAST tools can automate the process of identifying security vulnerabilities, which reduces the risk of human error and increases efficiency.
3. Faster and precise
SAST tools analyse applications and their source code more extensively and quickly than manual code reviews.
The technologies can quickly and accurately examine millions of code lines to look for underlying issues.
Additionally, SAST tools continuously check your code for security to maintain its functionality and integrity while assisting you in promptly resolving issues.
4. Comprehensive coverage
SAST tools can analyze the entire application, including both the source code and the compiled binary, which provides a more comprehensive view of potential vulnerabilities.
5. Integration with development tools
Developers can obtain security feedback while they work by integrating SAST with other development tools like IDEs and continuous integration/continuous delivery (CI/CD) pipelines.
DAST vs SAST: What is the difference between DAST and SAST?
DAST and SAST are both methods of testing the security of software applications, but they have some key differences:
| SAST | DAST | |
|---|---|---|
| Type | White-box application security testing. | Black-box application security testing. |
| Execution | SAST examines the source code or binary of an application without executing it. | DAST tests the security of an application by interacting with it as a user or hacker would. |
| Coverage | SAST examines the entire application, including the source code and the compiled binary, which provides a more comprehensive view of potential vulnerabilities. | DAST focuses on testing the application's external facing interfaces such as web services, web pages, and APIs. |
| Timing | SAST is typically performed during the development process. | DAST is typically performed after the application has been deployed. |
| False positives | SAST is more accurate but can miss some vulnerabilities that are only exploitable in runtime. | DAST tends to generate more false positives than SAST as it relies on identifying vulnerabilities by simulating real-world attacks. |
| Integration | SAST can be integrated with other development tools such as IDEs and CI/CD pipelines, which allows developers to receive security feedback as they work. | DAST is generally not integrated with development tools. |
DAST or SAST: Which one is right for you?
Determining whether DAST or SAST is the right choice for your organization depends on several factors, including:
1. Development process
SAST can be a preferable option if your firm uses a classic Waterfall development method because it is frequently carried out during the development process.
DAST can be a preferable option if your company uses an Agile development method because it is frequently carried out after the software has been deployed.
2. Security maturity level
SAST might be a preferable option if your company has an established security programme and a strongly outlined software development life cycle (SDLC), as it can be connected with other development tools like IDEs and CI/CD pipelines, enabling developers to get security feedback as they work.
Generally speaking, DAST is not integrated with development tools.
3. Resources
Due to the need to simulate actual application attacks and execute the programme in a test environment, DAST uses more resources than SAST.
SAST uses fewer resources because it analyses an application’s source code or binaries without running it.
4. Compliance
If your organization is subject to specific security regulations, such as PCI DSS or HIPAA, both SAST and DAST can help you comply with these regulations.
5. Risk level
Both SAST and DAST can be required to ensure the security of the application if it handles sensitive data and is a high-risk application for your company.
Ultimately, it’s important to note that both SAST and DAST have their own strengths and weaknesses and the best approach is to use both of them in a complementary way.
How to combine DAST and SAST for your application security
Combining DAST (Dynamic Application Security Testing) with SAST (Static Application Security Testing) helps boost the overall security of your application by giving you a much deeper understanding of any potential flaws in your application.
Here are some steps you can take to combine DAST and SAST for your application security:
1. Integrate DAST and SAST into your software development life cycle (SDLC)
Your SDLC should incorporate both DAST and SAST so that vulnerabilities can be found and fixed as early as possible throughout the development process.
2. Use SAST to scan your application’s source code
SAST can be used to check the source code of your application for potential security flaws.This can be accomplished either by executing a standalone SAST scan or by incorporating an SAST tool into your development environment.
3. Use DAST to test your application’s external-facing interfaces
DAST can be used to test your application’s external-facing interfaces, such as web services, web pages, and APIs, by simulating real-world attacks.
4. Combine the results from DAST and SAST
You should integrate the DAST and SAST results to get a comprehensive view of all potential vulnerabilities in your application.
5. Prioritize vulnerabilities
The vulnerabilities discovered by DAST and SAST should be prioritised depending on risk, and the highest priority vulnerabilities should be fixed first.
6. Continuously monitor
Continuously monitor your application for new vulnerabilities, and re-run DAST and SAST scans as necessary.
7. Train your developers
To help them build more secure code, train your developers how to identify and address the flaws that DAST and SAST have found.
By combining DAST and SAST, you can increase the overall security of your application by identifying potential vulnerabilities in both the source code and the running application.
Final thoughts
The majority of security events are caused by unfixed security flaws that the complex IT threat environment of today takes advantage of.
The solution is to do continuous and rigorous security testing to identify the weak points in your source code and overall application that malicious actors would inevitably locate and exploit.
The SAST and DAST approaches complement each other effectively, therefore combining the two is the most efficient approach that can bring a greater level of security to your applications.
