Software Dependencies

Introduction

In the process of crafting software applications, developers use a variety of programming languages and tools. However, these applications and systems don't exist in isolation; they heavily rely on other software components known as dependencies.

These dependencies, while essential, can introduce both efficiencies and potential vulnerabilities into the software development process.

This article provides a deep dive into software dependencies, exploring their types, the risks they pose, and the best practices for their management.

Whether you're an experienced developer or just stepping into this realm, this comprehensive guide offers valuable insights into optimizing software dependencies for secure and efficient software development.

📚 Related: Software Bill of Materials - SBOM

What is a software dependency?

A software dependency is a piece of software, or more specifically, a library, that a software system or application relies on to function.

These libraries contain code that has already been written and tested, which developers can reuse and incorporate into their software rather than building everything from scratch. Using software dependencies can save time and effort, as well as ensure consistency across multiple projects.

However, it also means that the software system is reliant on the external library, and any issues or bugs in the dependency can affect the entire system. Therefore, it is important for developers to carefully manage and update their software dependencies to maintain security and reliability.

Dependencies play a crucial role in software development, and the use of external libraries enables software developers to build applications much faster and more efficiently than creating every component from scratch.

It allows developers to concentrate on building new things without reinventing the wheel. To keep track of and manage these dependencies, developers often use a Software Bill of Materials (SBOM), which provides a comprehensive inventory of these software components.

More on managing in the last section.

How do dependencies impact the software supply chain?

Dependencies are an essential part of the software supply chain and can impact software development, deployment, and maintenance. A software supply chain involves multiple stages where software components and services are delivered from the development stage to the customers.

Properly managing dependencies can help secure the software supply chain and prevent any potential cyber-attacks.

📚 Related: Software Metadata

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Types of software dependencies

1. Direct dependencies

Direct dependencies are other software packages or modules that a particular software or module relies upon to function properly. These dependencies are explicitly listed in the source code or configuration file and are necessary for the software to be installed and work correctly.

Direct dependencies can include common third-party (open-source) libraries, runtime environments, APIs, and other specific software components.

2. Transitive dependencies

Transitive dependencies are dependencies of a project's dependencies. In other words, they are libraries or packages that a project relies on indirectly through its direct dependencies.

For example, if a project depends on library A, and library A itself depends on library B, then library B is a transitive dependency of the project.

These dependencies can impact the project's ability to compile or run properly, and managing them is an important part of software development.

This chain can continue for multiple levels, and it is important to manage and track all dependencies, both direct and transitive, to ensure the stability and security of the project.

3. Unused dependencies (extra)

Unused dependencies refer to software components or modules that are installed in a project or system but are not actually used or called by the application.

These dependencies can slow down the system, take up valuable memory, and even introduce security vulnerabilities, which is why it is important to regularly clean them up.

Unused dependencies can arise due to changes in the application requirements or because a developer might have installed a module as a potential solution but then decided on a different approach.

Risk of software dependencies

Risks associated with software dependencies became more relevant in recent years with the log4j incident. Software vendors and internal product teams now need to prevent dependency risks and understand all software components in the software supply chain.

But, it's not only about security risks. Check these most common dependency risks:

1. Security vulnerabilities: The use of outdated or unpatched libraries can result in security vulnerabilities, which can be exploited by attackers to gain unauthorized access.
2. Compatibility issues: Dependence on multiple libraries and frameworks can create compatibility issues. Changes or updates to one dependency can cause conflicts with others and lead to system errors and downtime.
3. Licensing issues: Failure to adhere to licensing agreements of software dependencies can result in legal fines and penalties.
4. Performance issues: Dependencies can impact application performance by increasing load times, memory usage, and processing overhead. Over time, this can lead to a noticeable decline in application responsiveness and usability.
5. Lack of maintainability: Dependence on third-party components can make it difficult to maintain and update software applications over time. This can lead to a decline in application quality and user experience.
6. Dependency hell: Dependency hell is a term that refers to the collection of difficulties developers face when managing dependencies. The difficulties arise when dependencies of dependencies conflict with each other. It can be hard to deploy, maintain, or update the software system in such cases.

To mitigate these risks, software vendors must carefully choose their dependencies. Instead of allowing the entire list of dependencies to auto-update, they must monitor the library's latest version, keeping an eye out for new vulnerabilities. Developers should also establish external libraries or modules' provenance and the official repository regularly.

Dependencies have revolutionized software development, making it possible for developers to build applications more efficiently. However, when unmonitored, the use of external libraries can introduce potential risks to your application.

By carefully selecting your dependencies and monitoring their latest update, engineering teams can avoid these risks and produce secure, reliable, and efficient software.

📚 Related: Understand Open-Source Licenses

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Tools and strategies for managing software dependencies

There are multiple options to choose from when you decide to secure and manage your software supply chain through software dependencies. Your selection will be based on your role and the needs of the organization.

To tackle dependencies specifically, here are 7 possible tools and strategies explained:

1. Generate and manage SBOMs

When it comes to constructing trustworthy and secure digital products, implement the shift-left approach to support the software supply chain.

Incorporate the CycloneDX Security Bill of Materials (SBOM) format and enable navigation of SBOMs to strengthen the security of your software supply chain.

As an engineer, you can consume SBOMs efficiently in an easy-to-use interface and filtering capabilities, while as an engineering leader, you can conduct a thorough evaluation of vulnerability exposure across your services and products.

Additionally, leaders can enhance response times by prioritizing and supervising remedial activities in a centralized manner.

2. Perform software dependency analysis

Software dependency analysis is the process of examining the relationships and dependencies between software components. It involves analyzing how different components interact, understanding their dependencies, and identifying potential issues or conflicts.

Dependency analysis helps ensure that the components work together harmoniously, avoiding compatibility problems and allowing for effective integration and maintenance.

3. Perform software composition analysis

Software Composition Analysis (SCA) is a process and toolset that examines the software supply chain and analyzes the composition of a software application.

It focuses on identifying and managing the open-source components and third-party libraries used within a software project.

SCA tools detect and report known vulnerabilities, licensing issues, and compliance risks associated with the software's dependencies.

4. Use a dependency management tool

A dependency management tool is specifically designed to handle dependencies in software projects. It allows developers to define the required dependencies, their versions, and any constraints or conflicts.

The tool resolves and retrieves the dependencies, ensuring that the software project has the necessary components to function correctly.

Dependency management tools work in conjunction with package managers, leveraging their capabilities to retrieve and manage dependencies.

5. Use a package manager

A package manager is a software tool that helps manage the installation, update, and removal of software packages or libraries.

It simplifies the process of managing dependencies by automatically handling the retrieval and installation of required components from repositories.

Package managers ensure that the necessary dependencies are available and properly integrated into a software project.

6. Use a dependency injection framework

A dependency injection (DI) framework is a software mechanism that facilitates the management and injection of dependencies into a software application.

It allows developers to define the dependencies required by a component and automatically provides those dependencies when the component is instantiated.

DI frameworks help decouple components, improve modularity, and simplify testing and maintenance by ensuring that dependencies are easily interchangeable and manageable.

7. Use a build tool

A build tool automates the process of compiling source code, linking libraries, and creating the executable or distributable artifacts of a software project.

Build tools manage dependencies, handle compilation, perform code generation, and execute various tasks required to build a software project.

They provide a streamlined and repeatable process for transforming source code into a deployable software application.

Conclusion

Software dependencies are critical components of modern software development. The use of external libraries helps developers create powerful and innovative applications while reducing development time and cost.

However, it's essential to manage dependencies effectively and stay vigilant against security vulnerabilities that may exist in the dependencies.

Developers and engineering leaders must take adequate measures to address these vulnerabilities as part of their software supply chain security and ensure a robust software development ecosystem.