Application dependencies occur when technology components, applications, and servers depend on each other to provide a business solution or service. Developers have a specific technology stack in mind when building solutions. This can typically include operating systems, database engines, and development frameworks (such as .Net or Java), as well as other infrastructure.
There are various types of application dependencies, such as libraries, plugins, databases, cache storage, and third-party services the application uses. If an application dependency is missing or has issues, it can affect functionality, user experience, security, and uptime.
Developers upgrade a dependency for various purposes, including security fixes, new feature releases, old version maintenance, and performance improvements. Unfortunately, the process of upgrading an application dependency is often time-consuming. For example, you might want to upgrade a specific library, but end up upgrading multiple libraries that depend on it in some way.
Developers add new libraries to a software project to provide new functionality and improve productivity. However, while these libraries can initially save time, they can later become a major burden on the project.
“Dependency hell” refers to problems that arise when software relies on other dependencies to function. This occurs when third-party software malfunctions and introduces bugs into other programs and applications. Understanding the causes of dependency hell is critical to avoiding or reducing its occurrence.
There is no single reason for dependency hell, but here are a few common causes:
- Code quality: It's usually better to use generic libraries that many developers trust, but generic libraries aren't without problems. Also, dependency vulnerabilities may not be discovered after use, and there may be hidden vulnerabilities. It is critical to check for vulnerabilities before using a library.
- Outdated codebase: There are scenarios where developers write code, then decommission it completely over time, and leave the code in place. Adopting this type of code exposes your project to vulnerabilities that can be expensive to fix.
- Dead code in dependencies: Dependencies may require downloading or using unnecessary dead code. As the project progresses, there may be overlapping dependencies with this dead code.
- Poor documentation: In some cases, documentation that informs others about the functionality of the program does not exist or is poorly written. Improving and reconciling software dependencies can be difficult without proper documentation, and will sometimes require starting from scratch.
These are just some of the scenarios where dependencies can cause problems. External packages and libraries are very useful, and no one argues that code reuse is not an important part of software engineering, but it must be done carefully and responsibly.
Application discovery processes enable Application Data Management (ADM) tools to identify and monitor the different components of a software product. Here are the three main traditional discovery methods:
- Sweep and Poll: This technique pings IP addresses and gathers response information to identify dependencies.
- Network Monitoring: Network traffic analysis can help identify the path packets take as they flow through the system.
- Agent-Based: This method involves installing a small software program on a server to monitor outbound and inbound traffic in real-time.
Some application discovery tools go beyond these traditional techniques, using orchestration platforms, Application Performance Monitoring (APM) tools, and advanced monitoring capabilities to identify and track application components and the underlying server resources.
Application mapping technology helps identify and map all instances, communication channels, and applications used within the entire IT ecosystem (including ports and services). Advanced solutions can also define subnets, virtual private clouds (VPCs), and security groups on clouds such as Azure, Google Cloud, and AWS.
The intuitive map features of these tools provide a visual representation of application dependencies. You can share, examine, and use these maps for various purposes, including troubleshooting and planning. It can help inform business strategies, organize information by business context, and prioritize critical alerts and information in real-time.
Cloud-native applications, which are designed to be deployed and run in a cloud environment, can also be impacted by application dependencies in terms of security. Here are a few ways in which application dependencies can affect the security of cloud-native applications:
Dependencies can introduce vulnerabilities
As with any application, if a cloud-native application depends on a library or framework that has a known security vulnerability, the entire application can be at risk. It's important to keep dependencies up to date and to carefully review and test them before using them in a production environment.
Dependencies can increase the attack surface
The more dependencies a cloud-native application has, the more opportunities there are for an attacker to try to exploit a vulnerability. It's important to minimize the number of dependencies an application has, especially those that are not strictly necessary.
Dependencies can compromise data integrity
If a cloud-native application depends on a library or framework that has been compromised, it could result in data being altered or corrupted. This can lead to data loss or breaches of confidentiality.
Dependencies can impact compliance
PCI DSS serves as a good example of a standard that requires organizations to ensure that all software dependencies are secure and regularly updated. Failing to properly manage dependencies can result in non-compliance.
Application dependencies are a critical part of cloud migration projects, and are often a key reason for security issues and downtime experienced during a migration.
The dependency chaining process
It is useful to visualize your application as a hierarchical structure. There is a chain of dependent tools and APIs, starting from the application's own interface, and continuing down to the platforms it is based on. The goal of dependency management is to identify combinations of versions that work together, so that your development team is aware of new and changing application dependencies.
You can control versions of your own application components to initiate this dependency chaining process. If you have software components to distribute separately, assign a version number to each component, and keep track of the underlying dependency chain for that version. This tells you the version of the specific platform tool associated with each application version. If for any reason you need to roll back, you can decide which other components need also to be rolled back to maintain version compatibility.
Synchronizing application versions and cloud environments
Because this approach requires changes to some platform components (including middleware), the platform versions of each application must be synchronized. To do this, always start at the top of the dependency chain. Developers design their applications to use specific operating system and middleware features, and expect "version X or later" of commonly used tools. For any given version of any tool, the developer has to check all dependencies, not just their own, until the end of the chain is reached.
Identifying hidden dependencies
Not all application dependencies are clear. For example, many developers face a problem where the hypervisor platform version must be compatible with the guest operating system on a physical host. Another common issue is when a specific version of an orchestrator, such as Kubernetes, requires a specific version of an operating system component. It is important to ensure that all dependencies are identified by testing each dependency chain against a standard operating system and middleware combination.
Cloud provider features and APIs
When you're ready to migrate to the cloud, ensure that each application's dependency tree includes all references to cloud provider features and APIs. Make sure you understand how cloud providers communicate changes to their APIs and tools. You should also be prepared to validate any new dependencies that these changes may create.
If you are planning a hybrid or multi-cloud deployment, compare these cloud dependency trees to understand all the applications and components that migrate across cloud platform boundaries. If two different providers have different dependency trees, you may have problems scaling or failing over between the platforms of those providers. To avoid this, synchronize the components beforehand.
Application dependencies are critical for cloud security because they can introduce vulnerabilities and expose sensitive data if not properly managed. By understanding and tracking dependencies, organizations can ensure that their applications are secure, making them compliant with industry standards and regulations.
Proper dependency management can also improve the performance and reliability of applications, as outdated or poorly designed dependencies can cause issues such as bugs and crashes.
About the Author:
Gilad David Maayan is a technology writer who has worked with over 150 technology companies including SAP, Imperva, Samsung NEXT, NetApp, and Ixia, producing technical and thought leadership content that elucidates technical solutions for developers and IT leadership. Today, he heads Agile SEO, the leading marketing agency in the technology industry.
LinkedIn: Gilad David Maayan
Editor’s Note: The opinions expressed in this guest author article are solely those of the contributor, and do not necessarily reflect those of Tripwire, Inc.