Software Composition Analysis (SCA): What You Should Know

Understand how SCA tools work, their primary use cases, how to choose an SCA tool, and SCA limitations you must be aware of.

What Is Software Composition Analysis?

Today’s software development landscape, with short release cycles, leads dev teams to rely heavily on open source to accelerate innovation. It is important, however, that each open source component included in an organization’s projects is tracked to avoid risks for legal non-compliance and to maintain a strong security posture. In a DevSecOps environment, this tracking must be integrated into every stage of the development lifecycle.

Software Composition Analysis (SCA) provides visibility into the open source components and libraries being incorporated into the software that development teams create. SCA can help manage security and license-related risks. It can help ensure that any open source component embedded in applications meets certain standards, to avoid introducing risks that could result in a data breach, compromised intellectual property, or legal disputes.

To accomplish this, SCA tools can identify specific open source versions, and correlate any associated security vulnerabilities and licensing information. Advanced SCA tools can automate the entire process, from detection and identification of components to vulnerability or license association and remediation of potential risks.

In this article:

SCA Use Cases

There are two primary use cases for software composition analysis—open source vulnerability management and open source license management.

Open Source Software Bill of Materials

Developers are becoming increasingly reliant on community-driven projects to accelerate development and innovation. Yet developers can quickly lose track of the many components available for use, and may lack visibility into dependencies associated with the components they bring into their projects.

SCA scans can generate comprehensive lists of the open source components present with software and containers, including any dependencies resolved into the project during the application build phase. 

The result is a Software Bill of Materials (SBOM), which includes fundamental information about detected open source components, including:

  • Component or library name
  • Version
  • Source or distribution
  • File path within the scanned project

Open Source Vulnerability Management

After generating an open source SBOM, SCA tools cross-reference detected component versions against databases of known open source vulnerabilities, such as the National Vulnerability Database (NVD). This can be done during dedicated application security testing, but should be done as early as possible in the development process to avoid introducing vulnerable components into the development pipeline.

With the completed SBOM in hand, teams can be notified of any newly published vulnerabilities affecting previously scanned projects. Therefore, SCA tools backed by adequate cybersecurity research can be critical for responding to zero-day threats. Knowing which of your projects or applications are affected by new vulnerabilities is a powerful benefit of software composition analysis, and can help accelerate remediation activities and minimize the potential window of attack if an exploit exists for associated vulnerabilities. 

Open Source License Management

While the nature of open source software enables access to core components and source code of a given project, the label of “open source” does not stipulate free use without restriction. There are thousands of open source licenses with unique requirements for those leveraging the source materials for individual or commercial use. SCA can detect licenses associated with the open source components within the software that developers create, and help to minimize the risk of license non-compliance. 

Open source licenses are most often defined by two categories:

Permissive licenses

These are among the most common types of open source license. Permissive licenses are often considered to be more aligned with the fundamental concept of open source, facilitating innovation without requiring compensation of any kind (e.g., financial, intellectual). Permissive licenses often place fewer restrictions on how a component’s code can be used and are, generally, considered to be less of a risk when detected within an organization’s software portfolio.

Reciprocal licenses

These are also known as “copy-left licenses.” They often require some sort of compensation or reciprocity for use of the component and its constituent code. For example, a license may require that any modifications made to the code in a separate development branch are made available for inclusion in the master branch of the originating project, or they may restrict the use of the component in commercial applications. These types of licenses are often considered to be more risky for organizations to use in commercial applications, as they can limit the potential business value or threaten the secrecy of intellectual property. 

SCA can help ensure that only open source components with appropriate licenses, as permitted by company policies, are used in your projects.

Related content: Read our guide to application security

The SCA Process

Here is how the SCA process usually works:

  1. The SCA solution scans a specified codebase and creates an inventory (SBOM) of all existing open source components, including dependencies that get resolved during the build process. 
  2. The solution documents specific information about the detected components, usually including license information, component version, and location of detection. The extent and accuracy of the information generated here is dependent on the completeness of the open source information database against which scan results are compared for identification. 
  3. The SCA solution identifies any associated open source security vulnerabilities, such as common vulnerabilities and exposures (CVEs).
  4. The tool can alert administrators or security stakeholders of any detected vulnerabilities or potential license conflicts. 
  5. Advanced SCA solutions can compare each detected open source component against defined policies and automatically block promotion of a project into production or notify stakeholders to accelerate the remediation process.
  6. Many SCA tools allow integration into CI/CD pipelines to automatically scan projects or new project versions with each commit. 

How to Choose a Software Composition Analysis Tool

Here are several important features to look for in an SCA tool:

  • A comprehensive open source database—while there are many sources which catalog publicly disclosed vulnerabilities, or open source components from a specific vendor or distribution, there is currently no centralized source of information on all open source components, licenses, or vulnerabilities. This information is, however, critical to ensure true risk visibility across the codebase. SCA tools should use a variety of information sources, including proprietary security research. This will enhance the probability of accurate component identification and risk association. 
  • Broad programming language support—SCA solutions must be able to scan applications written in a variety of programming languages, from the most popular to the most cutting-edge. Language support must be matched by the open source database in order to provide accurate information on associated risks. 
  • Create meaningful and comprehensive reports—SCA tools are designed to identify potential license and security risks. This information, however, can be useful only if provided in meaningful reports and delivered to those who can use it to mitigate risks. Ideally, your SCA tool should provide a variety of report features, integrations, and extensive APIs that can benefit stakeholders, including security, engineering, and DevOps teams, legal staff, and management.
  • Prioritization and remediation—Due to today’s rapid release cycles and distributed security and development teams, an SCA tool should help to prioritize the most severe issues and offer recommendations for remediation. Proper prioritization and verification of real risks can save significant time and effort, allowing teams to quickly fix issues. Often, these capabilities can be combined with policies to accelerate the issue management process and preclude critical risks.

Related content: Read our guide to DevSecOps tools

Limitations of SCA Tools

As with many application security testing tools, an SCA solution lets you detect potential issues, but it can be challenging to verify true risks, respond to those issues, and remediate them.

Assessment of Actual Risk

SCA tools can often generate lengthy lists of potential risks, including negligible risks and false positives which contribute to noise in the system and can delay remediation. Manual review of results is often required, which can consume valuable resources which should be spent on addressing true risks. 

When implementing an SCA solution across your organization, it is important to have practices in place to verify results, streamline review of scan results and analysis reports. Establish policies to alert relevant personnel who can make accurate assessments of the findings.

Risk Prioritization and Acceptance

Even when true risks are identified, many organizations can be challenged by determining which team is responsible for fixing a particular issue, since an at-risk component may be used across multiple projects owned by different teams. Additionally, because of the large quantity of potential risks that are commonly found in an organization’s codebase, teams can quickly become overwhelmed by long lists of risks without clear prioritization. 

When using an SCA solution, it is important to know which stakeholders should be notified for risks found in each analyzed project. Moreover, risks should be prioritized based on a variety of considerations. Some examples include:

  • What is the severity of the security risk?
  • Are risks present in business-critical applications? 
  • Could sensitive data be at risk if compromised?
  • Are exploits available for detected vulnerabilities?
  • Is the vulnerable component on a publicly accessible network, or remotely accessible?

It is important to determine who is authorized to decide whether a specific finding does or does not require fixing. Relying on the security team to provide approval could result in an objective and reliable decision—however, it could also slow things down for developers. Allowing developers to approve risks can speed up the pipeline, but will create a need to audit and monitor risk overrides.  

Technical Debt

If you retain a large codebase and have not been monitoring open source and third-party software, your initial SCA scans could likely show a sizable technical debt. 

Part of your technical debt will be due to your use of open source components or libraries that have been abandoned by the community. This places the responsibility upon your development teams to address any flaws, weaknesses, or vulnerabilities in the component. The result could be additional unforeseen development effort on open source libraries that are critical to your applications, or further development effort to refactor applications to function without the abandoned or at-risk library.

Ensure that your development and DevOps teams are educated on the importance of vetting open source and third-party libraries they ingest into their development pipelines. Foster security and license risk awareness, as well as an understanding of technical debt to safeguard the organizations against delays and stale code.

Gaps in Scanning Coverage

SCA solutions are only as capable as the tools that make them operate—a scanner to detect open source components, a database against which detected components can be evaluated, and a front-end tool to view and report on results. SCA scanners may not detect every third-party component in your scanned codebase. SCA databases may also not document particular libraries bought from small vendors or unpopular open source projects. For many SCA solutions, a degree of manual component tracking could still be required. 

Recall that software composition analysis is not equivalent to other traditional forms of application security testing, such as static application security testing (SAST), dynamic application security testing (DAST), penetration testing, or runtime analysis. SCA tools should, therefore, complement other cybersecurity solutions.

Software Composition Analysis with Aqua Security

Aqua’s cloud native application protection platform (CNAPP) provides powerful SCA capabilities to analyze containers, to detect open source and third-party components, and to identify any associated security vulnerabilities. Aqua’s container image scanning capabilities can be integrated into CI/CD pipelines and DevOps workflows to automatically trigger analysis at build or as containers are checked into registries. Configure and automatically enforce policies to ensure at-risk container images are not pushed to production.

Aqua provides enterprise-class solutions for container image scanning and maintains Trivy, the leading open source solution for vulnerability detection. 

Find out how to leverage Trivy and plot a path to full commercial coverage in this on-demand webinar.