In the case of software, businesses can protect themselves using Software Composition Analysis (SCA), a practice that helps identify security risks introduced by the “ingredients” in a software product. Read on for details as we explain what SCA means, how it works, why it’s important, and how to integrate SCA into your cybersecurity strategy.
In this article:
- What is Software Composition Analysis?
- What are the benefits of SCA?
- What are the key components of SCA?
- How does Software Composition Analysis work?
- Challenges of SCA
- Software Composition Analysis best practices
- Top open source SCA tools
- Getting started with SCA scanning using Trivy
- Software Composition Analysis with Aqua
What is Software Composition Analysis?
Software Composition Analysis (SCA) is a type of software security test that determines which third-party components exist in an application.
SCA focuses especially on the open source packages, libraries, and modules that developers incorporate into an application’s code base or include as dependencies. However, SCA can also, in some cases, reveal proprietary plugins, extensions, or other third-party components that are not open source but are integrated into an application or its runtime environment.
What are the benefits of SCA?
Software Composition Analysis is important for two main reasons: Managing security risks and ensuring license compliance.
Security risk management
First, SCA helps identify third-party components within an application that are subject to known security vulnerabilities. For example, imagine that an application’s developers integrate an open source encryption library into the app. Imagine, too, that that library has a security vulnerability that enables arbitrary code execution. By identifying the library and flagging it as vulnerable, SCA allows the organization to patch the vulnerability or otherwise take action to prevent threat actors from exploiting the risk.
SCA is particularly important in the context of security risks like these because in many cases, organizations don’t keep track of which components exist within applications they develop or use. Unless they generate a Software Bill of Materials (SBOM) for every app during the development process, they likely won’t know which libraries, modules, and other components it includes or whether they are vulnerable. But with SCA, they can inspect the application and gain visibility into its supply chain. In turn, they can help protect against supply chain attacks, which have become a growing risk as threat actors increasingly target the third-party software that organizations incorporate into their apps.
Licensing compliance
The second major use case for SCA is to determine which software licenses an application may need to comply with due to open source code that exists within the application. There are many open source software licenses, each with different requirements. To ensure compliance with relevant licenses, an organization must know which open source code exists in its applications, and which licenses govern that code.
Here again, using SCA to gain this visibility wouldn’t be necessary if organizations kept meticulous SBOMs that detailed the open source components inside an application and their licensing status. But because developers can easily incorporate open source code without remembering to keep track of it, SCA provides a safeguard to help organizations confirm that they’re not running afoul of open source licenses.
What are the key components of SCA?
SCA tools can provide information about virtually any type of component that exists within an application. That said, they typically focus on the following types of resources:
- Libraries, meaning read-only resources that an application calls when it operates in order to execute functionality not available in the app itself.
- Modules, which are code that can be imported into an application’s codebase to implement functionality without having to write the logic for it from scratch.
- Packages, or binary files used to distribute and install applications.
- Dependencies, meaning external applications or services that aren’t part of an application itself, but that are required to be present when the application runs (and that could therefore introduce security risks to any system that hosts an app with vulnerable dependencies).
How does Software Composition Analysis work?
Typically, SCA tools work by scanning an application codebase to identify distinct libraries, modules, or other components within it, as well as within any dependencies that are declared by the application or its packages. Then, the tools match those components against inventories of known software assets. If there are matches, the tools conclude that the software assets are present in the application. This approach makes it possible to identify components even if they are not labeled within the codebase.
SCA tools are most effective when they are able to access an application’s source code, since this provides the greatest level of visibility into application components. However, scanning of binaries (meaning applications that have been compiled) is also possible in some cases. In the latter case, SCA tools look for patterns or signatures in binary code that are similar to those associated with known software libraries, modules, or other components.
Challenges of SCA
While SCA is a powerful way to gain visibility into an application’s components and software supply chain, it presents some challenges:
- It only detects vulnerabilities associated with known software components. SCA is typically not effective for identifying security problems in “new” code written from scratch by an application’s developers.
- The risks or vulnerabilities that SCA tools help to identify may only be exploitable under certain conditions; thus, not every alert from an SCA tool necessarily signifies an actual risk.
- It may be less effective when scanning applications whose source code is not available, as noted above.
Software Composition Analysis best practices
To mitigate the challenges we just described and get the most from SCA, consider the following best practices:
- Complement SCA scans with other types of security tests, such as Static Application Security Testing (SAST), Dynamic Application Security Testing (DAST), and Dynamic Threat Analysis (DTA). These techniques can identify types of risks that SCA scans overlook.
- Integrate SCA scans into the secure software development lifecycle. This helps ensure that SCA is efficient and systematic.
- Scan application source code when it’s available, rather than scanning binaries alone.
- To reduce the risk of false positives or low-priority alerts, leverage risk-based vulnerability management techniques and consider vulnerability exploitability when assessing each alert.
Top open source SCA tools
Popular open source options for SCA scanning include:
- Trivy, a fast, comprehensive vulnerability scanner from Aqua Security that provides robust scanning and detailed vulnerability reporting.
- Dependency-Check, a basic SCA scanner that focuses primarily on identifying vulnerabilities linked to application dependencies.
- Dependency-Track, another scanner designed mainly for dependency validation.
Getting started with SCA scanning using Trivy
Using tools like Trivy, SCA scanning is easy. To perform a scan with Trivy, simply specify the name of the software you want to scan, along with optional arguments to control features like output formatting. From there, Trivy automatically downloads the software application or image you want to scan, and then generates a detailed scanning report.
For example, to perform a scan of the Python image on Docker Hub, run:
trivy image –pkg-types os python
The output includes a list of components and associated vulnerabilities:
Software Composition Analysis with Aqua
In summary, integrating SCA into your security strategy not only enhances your ability to manage security risks but also ensures compliance with open source licenses. By leveraging the right tools and best practices, organizations can gain a deeper understanding of their software supply chain and mitigate potential vulnerabilities before they become critical issues
As a comprehensive application security platform, Aqua Security provides SCA capabilities alongside a range of other features to help keep applications secure – and manage open source licenses to boot.
Learn more by requesting a demo.
