Understanding SCA: How Software Composition Analysis Helps Manage Software Supply Chain Risks

Modern applications are rarely written from scratch. Developers assemble products from proprietary code, open-source libraries, commercial modules, container images, system packages, and ready-made service components. This approach accelerates development but raises a critical question: who exactly knows what the application consists of?

SCA, or Software Composition Analysis, answers this question directly. The tool examines a project, locates third-party components, identifies versions, maps dependency chains, checks for known vulnerabilities, and reviews licenses. OWASP describes component analysis as a method for identifying risks associated with the use of third-party and open-source software parts, while the automated implementation of this approach is commonly called SCA. The method complements broader software supply chain protection because vulnerabilities can hide not in company code but in libraries that have not been touched for years.

What SCA Is Used For

The primary task of SCA is to give teams visibility. Without such visibility, developers and security teams operate almost blindly. The codebase may contain an outdated version of a popular library, a component with a conflicting license, or a dependency that has long been unsupported. Until a tool builds a map of the composition, the risk remains a guess.

SCA is applied at multiple stages. At an early stage, the tool checks new dependencies before they enter the main development branch. During the build process, SCA can block a release if the project contains a critical vulnerability or a prohibited license. After a version is released, the tool continues monitoring the same components because a new vulnerability may appear months or years later.

• Search for known vulnerabilities in third-party libraries and system packages;
• Control direct and transitive dependencies;
• Verify licenses and risks for commercial use;
• Generate a component inventory often called an SBOM;
• Monitor outdated, abandoned, or suspicious packages;
• Enforce rules that prohibit dangerous components in builds;
• Quickly assess affected applications after a new vulnerability is published.

SCA is also used to create a Software Bill of Materials. An SBOM records components, versions, dependency relationships, and metadata. CISA views SBOMs as the foundation of software supply chain transparency. SCA frequently serves as the data source for such inventories and later helps compare product composition against vulnerability databases.

Advantages Offered by SCA

SCA reduces reaction time. When a new dangerous vulnerability emerges, the team does not start a manual search across all projects. The tool already knows where the required library is located, which version is used, and through which dependency the component entered the application. For large organizations, the difference between hours and weeks can determine the outcome of an incident.

A second advantage relates to risk management rather than vulnerability discovery alone. An old, unsupported library may contain no known issues today but could become a source of urgent work tomorrow. A license may permit internal use yet block product sales. A package may have a name similar to a popular component and be used for substitution attacks. A good SCA solution reveals multiple types of risk instead of turning security into a list of red icons.

A third advantage appears in developers’ daily work. SCA does not require teams to read security bulletins manually. The tool suggests concrete actions: update the component to a safe version, replace the library, confirm that vulnerable code is not called in the project, or create an exception with a review date. The closer the check is to development, the fewer conflicts arise between speed and security.

How SCA Differs from Other Application Security Tools

Application security tools solve different tasks, although they often look similar on marketing pages. SAST (Static Application Security Testing) searches for errors in developers’ own code: unsafe input handling, memory management mistakes, weak cryptography, or command injection risks. SCA does not examine application logic; it examines composition—what external components entered the product and what risks each component carries.

DAST (Dynamic Application Security Testing) attacks a running application from the outside and looks for behavioral problems. Such a tool may find a vulnerable login form or incorrect header configuration but usually cannot report which library version resides inside a container. SCA, conversely, cannot prove that a specific entry point is exploitable via a web request, yet it quickly locates components with known vulnerabilities across many projects.

Boundaries between tools are gradually blurring. Many modern SCA platforms can analyze container images, while some container-scanning solutions incorporate application dependency data. The fundamental division of responsibilities remains: SCA handles composition, SAST handles proprietary code, and DAST handles runtime behavior.

What a Good SCA Solution Contains and Offers

A capable SCA solution first discovers components by reading manifest files, lock files, container images, archives, executables, and sometimes source code. It then matches discovered components against package databases, vulnerability databases, and license directories. The more accurate the recognition, the fewer false positives and missed dependencies occur.

The tool then evaluates risk, showing vulnerabilities, severity, available safe versions, the path by which a component entered the project, the existence of a fix, and potential product impact. Advanced systems add context: whether the vulnerable component is used in production code, whether the dangerous code path is reachable, and whether risk can be temporarily reduced through configuration or requires immediate library updates.

Another important layer involves exchange formats. In practice, SPDX and CycloneDX are frequently encountered. SPDX is the open international standard ISO/IEC 5962:2021 for describing software components and related information. CycloneDX focuses on composition, dependencies, and supply-chain security data. Formats alone do not protect a product but help transfer software composition information between developers, suppliers, customers, and analysis tools.

VEX (Vulnerability Exploitability eXchange) allows a supplier or team to explicitly state the status of a vulnerability in a specific product: affected, not affected, under investigation, or fixed. VEX is often supplied together with an SBOM so that the component list does not become a catalog of every CVE without understanding real product risk.

Who Needs SCA and How to Apply the Tools

SCA is needed not only by security teams. Developers use it to select dependencies before a library becomes part of the product. Development managers see technical debt and the volume of required updates. Security teams obtain a risk picture across applications. Legal departments review licenses. Procurement teams can request SBOMs from vendors and verify third-party products before deployment.

In Russian conditions, component accounting is becoming increasingly relevant in the context of GOST R 56939-2024 and FSTEC requirements for secure software development. For products requiring certification and proof of composition control, SCA assists both security specialists and those preparing evidentiary materials for development processes.

Implementation is best done gradually. A team first connects analysis to one or two projects, reviews the volume of findings, and tunes rules. Blocking all builds over every medium-severity vulnerability will cause developers to bypass the checks. Policies must consider product type, internet exposure, presence of personal data, system criticality, and support duration.

Limitations of SCA and Common Mistakes

SCA is not a magic button. The tool depends on the quality of component data, recognition accuracy, completeness of vulnerability databases, and correct project configuration. If a build downloads dependencies in a non-standard way, some components may be missing from the report. If developers copy foreign code manually without declaring a package, standard manifest analysis will not detect the fragment.

False positives also occur. A vulnerability may affect a function the application never uses. A component may exist only in a test environment. A package may have been built with vendor modifications that public vulnerability descriptions do not account for. Therefore, SCA should support decision-making rather than automatically declare an emergency for every new CVE identifier.

SCA does not discover zero-day vulnerabilities or issues absent from public databases such as CVE, GHSA, or OSV. The tool works only with known data. Checking should occur with every significant change rather than quarterly. SBOMs should not be treated as one-time documents because software composition changes with every release. Blocking everything without prioritization quickly leads to alert fatigue. License risks must not be ignored, as legal exposure sometimes surfaces later than technical issues. Exceptions without owners and review dates tend to become permanent. Finally, focusing only on direct dependencies is dangerous because transitive components often carry the main risk.

Why Software Composition Analysis Matters

Third-party components have become the norm rather than the exception. A logging library, authorization module, image parser, database client, and base container image can appear in hundreds of services. A single vulnerability in a popular component forces teams to check the entire application fleet. Without SCA, such verification turns into manual team surveys and searches through outdated tables.

Analysis of software composition is also important because risk changes after release. An application may have passed checks on release day, yet six months later the vulnerability database may contain a new entry. Teams that maintain version inventories quickly understand which products are affected. Teams without such inventories first try to recall where a library was used, then search for service owners, and eventually discover that some projects have long been unmaintained.

There is also a legal dimension. Open source does not mean absence of rules. Some licenses permit free use with almost no conditions, while others require disclosure of derivative works or retention of notices. For an internal system the risk may be moderate; for a commercial product or customer delivery the same component creates a different level of responsibility.