SAST vs. SCA: 7 Key Differences


Everybody’s talking about securing the DevOps pipeline and shifting left security. AppSec tools like SAST (Static Application Security Testing), DAST (Dynamic Application Security Testing), and others that address issues in proprietary software have become staples of the developer’s security toolbox. Unfortunately, SCA (Software Composition Analysis) tools are often left out since many of us forget that an AppSec strategy also needs to cover open source components with known vulnerabilities. Both SAST and SCA tools address vulnerabilities management, each one operates differently, covers a different set of vulnerabilities, and even integrates into different stages of the software development lifecycle (SDLC).

There are quite a few differences between SAST and SCA tools. SAST tools only detect security vulnerabilities in proprietary code by scanning an application’s code for flaws that are indicative of security vulnerabilities while the code is still in a static/non-running state. This helps developers remediate issues in their code before it’s deployed. While many SAST providers offer SCA solutions, they are not as comprehensive and effective as a dedicated SCA solution is.

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SCA tools detect and track all open source components in an organization’s code base, to help developers manage their open source components. Advanced SCA tools automate the entire process of managing open source components, including selection, alerting on any security or compliance issues, or even blocking them from the code. They also provide comprehensive information about the open source vulnerabilities discovered so that developers can easily fix them. SCA tools can be used throughout the SDLC, from creation to post-production.

7 Key Differences Between SAST and SCA

SAST and SCA comparison table

In order to clarify the differences, we created this list detailing the seven ways that SAST and SCA are different:

#1 Vulnerabilities Detection

First, let’s take a look at the different ways that SAST and SCA tools detect vulnerabilities.

SAST tools scan an organization’s in-house-written code for potential vulnerabilities, based on a set of predetermined rules. SCA tools track an organization’s software projects to detect open source components with known vulnerabilities and provide detailed security information about the vulnerabilities to help developers remediate them swiftly.

#2 Requires Source Code Access

SAST tools focus specifically on analyzing source files. That means that they can only scan a product’s source code. SCA tools identify both source files and binaries. Rather than scanning a product’s source code, an SCA tool calculates digital signatures for all libraries and detects the vulnerable open source libraries, without requiring organizations to expose source file information in order to identify the component.

#3 Remediation

When using SAST, developers need to begin each remediation process by investigating the potential vulnerability in order to validate it. Once confirmed, developers need to define the best remediation path. Open source vulnerabilities detected by an SCA tool are easier to fix since  97% of all open source vulnerabilities have a fix validated by the open source community and developers simply need to patch or download the latest version.

#4 SDLC Integration

SAST and SCA tools can both be integrated early in the development process to help developers catch vulnerabilities as early as possible before they become more expensive and time-consuming to fix. While both SAST and SCA tools integrate with CI servers and IDEs, only SCA tools offer end-to-end SDLC coverage all the way to post-deployment — providing coverage for vulnerabilities discovered years after release.

#5 False Positives

SAST tools often have a relatively high number of false positives because they scan source code for patterns of potential security issues, resulting in anywhere between 30% to 70% of false positives in scan results. SCA tools, by contrast, are not looking to detect new vulnerabilities but to identify the open source components that have known vulnerabilities associated with them. Since the task here is to accurately identify vulnerable open source components, with the right SCA tool, it is much easier to have zero false positives.

#6 Timeframe

Running SAST scans is often a time-consuming task. Aside from the fact that some can take quite a few hours to run, the process then requires additional time and manpower for research and validate the potential issues that come up in the results. Advanced SCA tools run within seconds, no matter what the project size.

# 7 Risk Coverage

SAST tools specifically focus on the security aspect of the organization’s code, which typically amounts to 10% to 20% of an organization’s code base. SCA tools address all aspects of open source management, including security and license compliance by using automated workflows that simplify developers everyday tasks.

SAST vs. SCA: The Secret to Covering All of Your Bases

As you can see, comparing SAST to SCA is like comparing apples to oranges. Both of these tools help developers ensure that their code is secure. However, each one addresses different kinds of issues and goes about it in a very different way.

SAST is not better or worse than SCA. Each tool deals with a different set of issues, using a different technology. Our best advice is to work with vendors that understand the differences and offer a dedicated, comprehensive solution for each.

That’s the first step in making sure that you’ve got all of your security bases covered.

Meet The Author

Ayala Goldstein

Ayala Goldstein is a writer at WhiteSource. She writes about everything open source, AppSec, and DevOps.

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