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Stepping Up Cybersecurity: An In-depth Look at SCA and SAST

As organizations mature their cybersecurity strategy and look for ways to more comprehensively secure their environment and assets, application security (AppSec) is of paramount importance. As threats grow in complexity and developer environments are becoming an often-targeted area, organizations must continually adapt their security strategies to safeguard their applications and software development lifecycle (SDLC). Two traditional AppSec security tools have emerged as foundational: Software Composition Analysis (SCA) and Static Application Security Testing (SAST). 

Both of these tools provide distinct yet complementary approaches to enhancing AppSec, making them invaluable components in the toolkit of any organization dedicated to maintaining robust cybersecurity. 

This article delves into more details around SCA and SAST, defining their methodologies, their histories, and highlighting their benefits and potential limitations. It also offers guidance on when to utilize each tool. The goal is to provide a comprehensive understanding of these key AppSec tools, helping organizations optimize their cybersecurity frameworks and navigate ever-increasing complex environments to protect against software supply chain threats.  

Understanding the Terms: SCA & SAST

Two techniques that are quite important in the world of application security testing (AST) are Software Composition Analysis (SCA) and Static Application Security Testing (SAST). Each of them offer a unique approach to safeguarding applications from potential security threats, and it’s important to understand their application context, strengths, and weaknesses. By exploring SCA security as well as comparing SAST vs SCA, we can better navigate the complex landscape of cybersecurity. 

Software Composition Analysis (SCA): What is the SCA and its meaning? 

Software Composition Analysis (SCA) serves as a proactive measure in identifying potential security vulnerabilities. As an automated procedure, it meticulously keeps track of every open-source component within an application's codebase. This not only gives developers a comprehensive view of the components they are working with, but also enables them to evaluate security, license compliance, and code quality. 

SCA originally entered the developer lexicon in the early 2000s and emerged as open-source components began gaining popularity in software development. Over the next decade, by 2011, the landscape of software development shifted towards agile methodologies and SCA tools adapted to accommodate the rapid development and iterative nature of agile practices. In 2018, SCA technology was enhanced to deliver insights beyond the application components and paved the way for a more comprehensive vulnerability assessment and mitigation process. 

The benefits of Software Composition Analysis (SCA) include: 

Time Savings: As an automated process, SCA can significantly reduce the time spent tracking and evaluating open-source components within an application's codebase. 

Comprehensive Scans: SCA can scan components as well as libraries, providing a thorough overview of all open-source aspects of an application. 

End-to-End SDLC Coverage: SCA can provide complete coverage throughout the Software Development Life Cycle, identifying vulnerabilities that may arise at any stage. 

Quick Working Times: Thanks to its automated processes, SCA can quickly evaluate and report on the security, license compliance, and quality of open-source components. 

Low False Positive Rates: SCA testing typically yields low false positive rates, minimizing the risk of spending time and resources addressing non-issues. 

However, SCA isn’t without its downsides and challenges. 

The deployment of SCA can be relatively complex and labor-intensive, potentially taking months to fully operationalize. There can also be a lack of consistency as there is considerable variation in the proprietary databases of Open Source Software (OSS) components across different products and the ones that SCA tools use. Depending on the tool, its vulnerability data may not be as comprehensive. If, for example, it only reports on vulnerabilities officially recognized in the National Vulnerability Database (NVD), it may leave a blind spot in your security strategy where vulnerabilities are identified months after their original discovery. 

While SCA is an automated scanning tool, it doesn’t necessarily mean post-scan actions are automated. These SCA tools may lack automated guidance on what actions to take and may not have details on the legal requirements of detected OSS licenses, which may lead to compliance issues and tax an already strapped AppSec team. 

Static Application Security Testing (SAST)

As opposed to SCA, Static Application Security Testing (SAST) adopts a more preventive approach by taking place earlier in the SDLC. Often referred to as white-box testing, SAST involves scanning an application before it is compiled. It uses a structural testing methodology that scrutinizes source code and identifies security vulnerabilities that could make the application susceptible to attacks. By using predetermined rules, SAST tools can examine an application's codebase for potential vulnerabilities. Conducted early in the development process, at the code level, and also when all pieces of code and components are assembled in a consistent testing environment, SAST offers a preemptive strike against potential threats throughout the SDLC and is an effective form of application and software quality testing. 

Although SAST has been a part of computer science since its inception, its widespread adoption didn't occur until the late '90s. This shift coincided with the emergence of SQL injection attacks and risk, which became part of the public cybersecurity discourse. So a new form of analysis and testing was required. 

The benefits of Static Application Security Testing (SAST) include: 

Detection of Code Flaws: SAST has the ability to detect potential code flaws such as Common Weakness Enumerations (CWEs) which could pose security risks. 

High Precision: When correctly configured, SAST can offer a high degree of precision in detecting potential vulnerabilities. 

Time and Cost Savings in CI/CD: In a Continuous Integration/Continuous Deployment (CI/CD) context, SAST can halt integrations if critical vulnerabilities are discovered, saving both time and money. 

Full Coverage of Source Code: If correctly configured and implemented, SAST can cover 100% of written source code, providing comprehensive visibility into potential security vulnerabilities. 

Extended Functionality: Beyond identifying potential security issues, SAST also offers extended functionality, such as quality and architectural testing. 

However, just like SCA, SAST also has several limitations: 

SAST needs to have access to the source code to perform scans, which is not always feasible, depending on your environment’s make-up and if you have a complicated developer environment. Because SAST takes place in the early phases of the SDLC, it doesn’t offer end-to-end coverage like SCA does. Finally, depending on your SAST tool (there are open-source SAST tool as well as non-open source options) there's the potential for a high number of false positives, which can lead to unnecessary mitigation efforts and too much noise. 

When considering SCA vs. SAST, there are several factors worth taking into account. 

Breaking Down When to Use SCA vs. SAST

The decision to employ Software Composition Analysis (SCA) or Static Application Security Testing (SAST) often depends on your developer environment’s make-up and the resources you and your department have available. Each tool offers a distinct approach to safeguarding your apps and systems, and understanding these differences can help you improve your overall SDLC security. Here are some important factors to be aware of. 

Vulnerability detection: Both SCA and SAST have the ability to detect vulnerabilities, which is why they’re so important. SCA scans open-source components, making them more valuable for any projects or environments with a heavy reliance on open-source tools or systems. On the other hand, SAST comprehensively scans your own source code for potential vulnerabilities, based on a set of predetermined rules, identifying weaknesses before an application is even compiled. Each tool looks at different aspects of your entire project’s code so whether you’re utilizing open-source components heavily or not should be a major consideration on whether to use SCA or SAST.   

Access to source code is also an important consideration. Because of where SCA and SAST scan for vulnerabilities, SAST requires access to the source code, making it more suited to in-house developments. SCA, however, can work without direct source code access, making it more applicable in scenarios where third-party components are employed. 

SDLC integration: SCA offers end-to-end SDLC coverage, making it a more comprehensive tool for the entire SDLC, especially if vulnerabilities might emerge well into a product’s lifecycle. SAST is performed early in the SDLC, making it a more proactive approach that can be utilized at the start of any projects or software development programs. 

Pros and Cons: Depending on your organization’s make up, some potential downsides of either SCA or SAST may be more impactful than others. SAST offers more comprehensive scanning but may result in higher false positives, which may not be something your current department can handle at the moment. SCA may be best if you’re working heavily with open-source components but you may need to consider SAST for projects that require more in-house project development. 

For example,if you're developing an application that heavily relies on open-source components, employing SCA scanning would be beneficial due to its expertise in detecting vulnerabilities within these components. Conversely, if you're working on an in-house development where you have full access to the source code and want to identify and fix vulnerabilities proactively and early in the SDLC, SAST would be the tool of choice. 

 Lastly, the choice between SCA and SAST doesn’t have to be locked in and isn’t always binary. You can utilize both tools in conjunction, especially as part of a more comprehensive AppSec security strategy. Knowing when and how to deploy these options can help make your SDLC much more secure in a proactive and continuous way. 

Amp Up Your Application Security with Comprehensive AppSec Tools 

Understanding how to best leverage any security tools you have access to is just as important as obtaining the tools themselves. Both Software Composition Analysis (SCA) and Static Application Security Testing (SAST) play significant roles in securing your applications and should be used in conjunction, especially as environments become more complex and shift often. Consider the strengths, weaknesses, and limitations of each in order to better utilize them as part of your SDLC cybersecurity framework. 

SCA, with its ability to monitor open-source components and provide end-to-end SDLC coverage, is an excellent asset when dealing with vulnerabilities that may arise long after product deployment. On the other hand, SAST excels in early vulnerability detection in your source code, helping prevent potential security breaches before the application goes live.

Don’t think of your choice being between SCA vs. SAST — rather, it’s about how to leverage each of these tools best and knowing when and how to use them. Even more importantly, be aware that SDLC and AppSec security doesn’t end at the use of SCA and SAST. These are code scanning tools that have robust capabilities but don’t cover all potential vulnerabilities that may emerge within the SDLC. 

You should look for additional tools and applications that provide full-scope risk identification and vulnerability assessment throughout the entire SDLC which includes systems, people, processes, environments, and applications — not just code. Ready to learn more? Schedule a product demo or check out the Legit Security Platform. 

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Published on
June 27, 2023

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