How to Choose a Software Composition Analysis (SCA) Tool

By identifying risks within code that developers can easily overlook, Software Composition Analysis (SCA) tools play a vital role in helping to manage both security risks and open-source licensing risks. This article explains how SCA tools work and offers tips on what to look for when comparing SCA options.

What is Software Composition Analysis?

Software Composition Analysis is the use of automated tools to identify open source components within an application’s code base. SCA tools scan software, determine which dependencies and other contents exist within it, then identify the original sources of those components.  In this way, SCA tools determine  which parts of a codebase have been obtained from third-party sources.

Why is SCA important?

Software Composition Analysis is important for two main reasons.

First, it helps organizations avoid security risks associated with the reuse of open source code that may contain known vulnerabilities. SCA tools can detect insecure modules or dependencies used within an application. They may also be able to identify instances where developers copy insecure code into an application.

Second, SCA helps developers ensure that they are complying with software licenses that govern source code they reuse. There are more than 80 open source licenses in existence, each with different rules and terms regarding how source code may be reused. With SCA tools, developers can automatically determine which licenses apply to their code and address any licensing compliance violations.

Both of these tasks — identifying insecure source code and identifying licensing issues — are especially important today, given the widespread reuse of open source code within applications. GitHub alone hosts more than 128 million public repositories, which contain code that anyone can easily copy-and-paste into an application. However, just because developers can borrow code doesn’t always mean that it’s secure to do so. Nor does it mean that the license associated with the code gives them the right to reuse the code in the way they plan to. By tracing source code back to its origin, SCA tools address both of these issues.

SCA tools are also particularly important today because of the prevalence of supply chain security risks. Supply chain security risks arise when an organization imports insecure third-party software into its own applications. SCA tools allow developers to scan their applications automatically and identify instances where they may have inadvertently imported insecure code from an external source.

Which risks can SCA tools detect?

SCA tools can identify a variety of risks in open source software. Among the most common, as noted above, are modules or dependencies that are subject to known security vulnerabilities. SCA tools may also be able to detect malware that is embedded within source code, which could arise in situations where attackers gain access to an organization’s CI/CD tools and use them to inject malicious code into applications.

In addition, as we’ve noted, SCA tools can identify potential software licensing violations. They may not be able to tell developers whether they’re complying with a given software license, but they can alert developers to open source licenses that apply to the applications developers manage. In turn, developers or open-source software compliance managers can research the licenses to ensure that they are using the code properly.

It’s important to note that SCA can’t identify every type of security or licensing risk. In general, SCA tools are only capable of detecting risks associated with open source code. If developers import proprietary third-party code into an application, the code is not likely to be part of the databases that SCA tools use to trace the origins of source code. Therefore, the tools won’t be able to identify the code.

Tips on choosing an SCA tool

As open source software has become widespread across codebases, the number of SCA tools on the market has grown rapidly. But not all SCA tools offer the same capabilities and areas of coverage. When selecting SCA tools, be sure to evaluate the following areas of functionality:

• Language support: When possible, choose an SCA tool that can support any type of programming language or framework, instead of those that only work with specific languages.
• Support for binary and source code scanning: While some SCA tools can only work with source code, the best SCA tools are capable of scanning both source code and application binaries in order to identify risky components. The ability to scan binaries gives teams visibility into closed-source software packages (such as applications obtained from third-party vendors), whose source code is not typically available.
• Automated codebase scanning: Instead of SCA tools that have to be executed manually, or that analyze codebases file-by-file, look for tools that can scan an entire codebase automatically and continuously. That way, you can automatically scan code as it is integrated into your codebase, even when working with complex applications with sprawling sets of source code files.
• CI/CD integration: SCA tools that support CI/CD integration can streamline the SCA process by scanning code from directly within Continuous Integration (CI) servers or artifact repositories. In this way, CI/CD integration helps developers detect issues as early as possible within the development lifecycle.