What is Static Application Security Testing (SAST) and how does it work?

What is SAST?

Static Application Security Testing (SAST), or static analysis, is a method of testing and analysing source code. This method allows organisations to analyse their source code and detect vulnerabilities that could make their applications prone to attacks.

This methodology has been used in application security for over 15 years and is especially useful for helping developers spot possible security weaknesses in the early stages of software development.

Learn more about the different types of AppSec tools and how SAST fits into the mix

How Does SAST Work?

As the ‘static’ in the name implies, SAST tests work with static code (code at rest). This means you don’t have to run the code to test for any vulnerabilities.

These are the 6 steps to a SAST test:

• Tool finalisation - Select a static analysis tool that can review your programming language.  

• Infrastructure and tool deployment - Create the scanning infrastructure. This includes licensing, authorization, and resource procurement. 

• Tool customisation -  Make custom tweaks to the tool according to your software needs. This could include decreasing false positives or discovering other security vulnerabilities by writing new rules or updating current ones.  You can also fine-tune the tool to suit your organization’s needs.

• Prioritisation and onboard application - When the tool is prepared, onboard your applications, prioritizing the high-risk applications first. Eventually, every application should be onboarded and regularly scanned.

• Analyse scan results - Filter out the false positives. Once they’re removed the results should be handed to the deployment team for remediation.

• Governance and training - Ensure the scanning tools are being used properly. SAST should be included in your application development process.

Remember: the best time to implement SAST is during the early stages of development. However, it’s important to note that SAST tools should be an integral part of an ongoing process. SAST scans should be employed regularly, such as every time code is checked in, or during a code release.

What Kind of Vulnerabilities can SAST Tools Detect?

Some of the most common flaws encountered by SAST scans are:

•  SQL injection
• Input validation
• Stack buffer overflows  

Advantages of SAST Tools 

SAST tools are a great way of shifting security left. Shifting left means security testing starts from the beginning of the development process instead of implementing scans later on.

The earlier you start testing the better. If you find your security weaknesses right from the start of your design stage, the effort it will take to fix them will be greatly reduced when compared to late-stage testing.

The worst-case scenario is finding security flaws very close to, or even after, the release date, which often means added stress and costs.

SAST vs DAST

While SAST can detect vulnerabilities without running the code, DAST (Dynamic Application Security Testing) can find them in a running application.

While SAST testing is completed by the developers themselves or by someone who has access to the code, DASTs are conducted from the outside in, with the tester being unaware of which technologies and frameworks compose the software. SAST is a type of white-box testing, which is often referred to as the developer approach, while DAST is a type of black-box testing, often described as the hacker approach.

DAST works by deploying fault injection techniques on an application, such as sending malicious data to the software to identify common security issues.  Another great feature of DAST is discovering problems related to runtime, something which isn’t possible with SAST.

As both SAST and DAST have their own set of advantages and disadvantages, they’re often used in tandem.  SAST won’t discover runtime errors, whilst DAST fails to flag coding errors.    

Conclusion

In today’s world, it is strongly recommended to include security testing in your application development. By using SAST and DAST together, you can benefit from a fast and effective approach to creating more secure applications.  

Who is Uleska?

Uleska helps security and development teams manage application security at scale by automating and orchestrating their preferred security tools within CI/CD.

With Uleska, teams can confidently start an AppSec program using open-source, commercial, and custom tools and then quickly change, add or scale tools as the technology and business needs evolve. Uleska also brings speed and scale when integrating into development tools, and reporting of metrics and risk.

By bringing security, DevOps and development teams together, we help reduce manual tasks so application security takes less time, cost and can scale, allowing teams to focus resources on the issues and metrics that matter.