In an era where web and mobile applications power nearly every aspect of our digital lives, ensuring their security is no longer optional – it’s a critical imperative for developers, businesses, and users alike. As cyber threats evolve in sophistication, from data breaches to sophisticated injection attacks, organizations must adopt robust app security strategies to identify and mitigate vulnerabilities before they can be exploited.

This blog post delves into three cornerstone approaches in application security: Static Application Security Testing (SAST), which scrutinizes code in its static form; Dynamic Application Security Testing (DAST), which probes a running application like a real-world attacker; and traditional penetration testing, the hands-on simulation of cyberattacks by skilled ethical hackers.

By understanding the differences between these methods – their strengths, limitations, and ideal use cases – you’ll be better equipped to fortify your apps against emerging risks and build more resilient software.

SAST (Static Application Security Testing)

What it does: SAST is a way to check your app’s code for security problems before the app is run.  It looks at the code line by line to find weak spots and helps fix problems early before the app goes live.  

Why is it useful: By catching issues early in the development process, SAST saves time and money, improves code quality, and fits naturally into a developer’s workflow. Since it doesn’t require the app to be built or run, security checks can be performed continuously as the code is written.

Limitations: It can’t detect issues that appear only when the app is running and may struggle with complex or dynamic code. Scans can be slow on large projects, and messy code can reduce accuracy.

Example limitations: server configuration, network issues.

DAST (Dynamic Application Security Testing)

What it does: It searches for security problems by testing a running application from the outside – kind of like a hacker would. Instead of looking at the code, DAST interacts with the live app to see how it behaves and checks for vulnerabilities that appear during actual use.

Why is it useful: It tests the app while it’s running, just like a real user or attacker would. This helps find problems that only happen when the app is being used, like mistakes in how it handles information or settings that aren’t safe. Since it checks the live app from the outside, it can catch issues that might be missed by looking at the code alone. This makes sure the app is safer and less likely to be broken into or misused.

Limitations: It only finds problems that happen while the app is running, so it might miss issues hidden deep inside the code that don’t show up during testing. It can’t see the actual code, so it may miss some security flaws that a code review would catch. Also, testing a live app can sometimes be slow and may not cover every part of the app perfectly.

Penetration Testing

What it does: Penetration testing is a thorough check where security experts try to break into an app or its systems, just like a real attacker would. They look for weaknesses, try to take advantage of them, and then analyze what damage could happen if those weaknesses were used by someone with bad intentions. This helps find problems so they can be fixed before real attacks occur.

Why is it useful: Penetration testing checks not just the app, but also the servers, networks, and sometimes even how people might be tricked, like through phishing emails. It goes deeper than simple automated tests by having experts look carefully for problems, combine different weaknesses, and find mistakes in how the app works that could cause trouble.

Limitations: It can take a lot of time and effort, plus it’s much more expensive, so it’s usually done only occasionally and not all the time. Because it relies on people trying to find weaknesses, it might miss some problems. Also, tests focus on specific parts of the app or system, so some areas might not get fully checked. Finally, penetration testing can’t guarantee that an app is completely secure – it just helps find and fix many of the biggest risks.

Key Differences: Penetration testing, SAST, and DAST all help find security issues, but they work in different ways and at different stages. SAST examines the app’s code without running it, allowing developers to catch problems early during development or post-launch updates. DAST tests the app while it’s running, checking how it behaves in real use to spot vulnerabilities like configuration mistakes or how it handles user input. Penetration testing goes further by simulating real human attacks on the running app, servers, and networks, often involving manual efforts by security experts to uncover deeper or more complex weaknesses. While SAST and DAST are mostly automated and can be done regularly, penetration testing is usually done occasionally for a more thorough, realistic look at security risks. Together, these methods provide a well-rounded approach to keeping applications safe.

Can SAST & DAST Be Claimed as a Penetration Test?

No, not fully. While SAST and DAST are important parts of checking an app’s security and are often tools used during penetration testing, they don’t cover everything a full penetration test does. A penetration test usually involves:

• Manual testing: Human testers try to find and take advantage of weaknesses that automated tools might miss, like ways to gain higher access or problems with how the app handles permissions.
• Wider focus: It goes beyond the app itself to check servers, networks, APIs, and sometimes other parts like external devices that support the whole system.
• Real-world simulation: It imitates how actual attackers would try to break in, including trying different ways to bypass security protections or exploit mistakes in setup.

Conclusion

While SAST and DAST scans are helpful and important when checking an app’s security, they have their limits. SAST only looks at the app’s code and can miss problems that happen when the app is actually running. DAST runs automated tests on the live app but might not catch complex issues that need creative human thinking, like combining small problems to cause bigger damage. Neither of these includes hands-on testing by experts or detailed reports about what an attacker could do if they broke in.

In our opinion, owners of a web app or SaaS platform should perform regular SAST and DAST vulnerability scans to help ensure that their app is secure on an on-going basis. It’s an important part of having a strong security posture within an organization. However, understanding your requirements is just as important because SAST and DAST scans will be much less expensive than if you were to require a full-blown penetration test by certified security professionals.

Oracast Staff

• Application Security