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The Complete Guide to Software Supply Chain Security

Updated on April 3, 2024

Prevent software supply chain attacks with industry-leading security solutions from Anchore.

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    The mega-trends of the containerization of applications and the rise of open-source software components have sped up the velocity of software delivery. This evolution, while offering significant benefits, has also introduced complexity and challenges to traditional software supply chain security. 

    Anchore was founded on the belief that the legacy security solutions of the monolith era could be rebuilt to deliver on the promises of speed without sacrificing security. Anchore is trusted by Fortune 100 companies and the most exacting federal agencies across the globe because it has delivered on this promise.  

    If you’d like to learn more about how the Anchore Enterprise platform is able to accomplish this, feel free to book a time to speak with one of our specialists.

    If you’re looking to get a better understanding of how software supply chains operate, where the risks lie and best practices on how to manage the risks, then keep reading.

    An overview of software supply chains

    Before you can understand how to secure the software supply chain, it’s important to understand what the software supply chain is in the first place. A software supply chain is all of the individual software components that make up a software application.

    Software supply chains are similar to physical supply chains. When you purchase an iPhone all you see is the finished product. Behind the final product is a complex web of component suppliers that are then assembled to produce an iPhone. Displays and camera lenses from a Japanese company, CPUs from Arizona, modems from San Diego, lithium-ion batteries from a Canadian mine; all of these pieces come together in a Shenzhen assembly plant to create a final product that is then shipped straight to your door. In the same way that an iPhone is made up of a screen, a camera, a CPU, a modem, and a battery, modern applications are composed of individual software components (i.e. dependencies) that are bundled together to create the finished product.

    With the rise of open source software, most of these components are open source frameworks, libraries and operating systems. Specifically, 70-90% of modern applications are built utilizing open source software components. Before the ascent of open source software, applications were typically developed with proprietary, in-house code without a large and diverse set of software “suppliers”. In this environment, the entire “supply chain” were employees of the company which reduced the complex nature of managing all of these teams. The move to Cloud Native and DevSecOps design patterns dramatically sped up the delivery of software with the complication that the complexity of coordinating all of the open source software suppliers increased significantly.

    This shift in the way that software is developed impacts essentially all modern software that is written. This means that all businesses and government agencies are waking up to the realization that they are building a software supply chain whether they want it or not.

    One of the ways this new supply chain complexity is being tamed is with the software bill of materials (SBOM). A software bill of materials (SBOM) is a structured list of software components, modules, and libraries that are included in a given piece of software. Similar to the nutrition labels on the back of the foods that you buy, SBOMs are a list of ingredients that go into the software that your applications consume. We normally think of SBOMs as an artifact of the development process. As a developer is “manufacturing” their application using different dependencies they are also building a “recipe” based on the ingredients.

    What is software supply chain security?

    Software supply chain security is the process of finding and preventing any vulnerabilities that exist from impacting the software applications that utilize the vulnerable components. Going back to the iPhone analogy from the previous section, in the same way, that an attacker could target one of the iPhone suppliers to modify a component before the iPhone is assembled, a software supply chain threat actor could do the same but target an open source package that is then built into a commercial application.

    Given the size and prevalence of open source software components in modern applications, the supply chain is only as secure as its weakest link. The image below of the iceberg has become a somewhat overused meme of software supply chain security but it has become overused precisely because it explains the situation so well.

    A different analogy would be to view the open source software components that your application is built using as a pyramid. Your application’s supply chain is all of the open source components that your proprietary business logic is built on top of. The rub is that each component that you utilize has its own pyramid of dependencies that they are built with. The foundation of your app might look solid but there is always the potential that if you follow the dependencies chain far enough down you will find a vulnerability that could topple the entire structure.

    This gives adversaries their opening. A single compromised package allows attackers to manipulate all of the packages “downstream” of their entry point.

    This reality was viscerally felt by the software industry (and all industries that rely on the software industry, meaning all industries) during the Log4j incident.

    Common software supply chain risks

    Software development is a multifaceted process, encompassing various components and stages. From the initial lines of code to the final deployment in a production environment, each step presents potential risks for vulnerabilities to creep in. As organizations increasingly integrate third-party components and open-source libraries into their applications, understanding the risks associated with the software supply chain becomes paramount. This section delves into the common risks that permeate the software supply chain, offering insights into their origins and implications.

    Source code

    Supply chain risks start with the code itself. Below are the most common risks associated with a software supply chain when generating custom first-party code:

    1. Insecure first-party code

    Custom code is the first place to be aware of the risk in the supply chain. If the code written by your developers isn’t secure then your application will be vulnerable at its foundation. Insecure code is any application logic that can be manipulated to perform a function that wasn’t originally intended by the developer.

    For example, if a developer writes a function that allows a user to login to their account by checking the user database that a username and password match the ones provided by the user but an attacker crafts a payload that instead causes the function to delete the entire user database this is insecure code.

    2. Source code management (SCM) compromise

    Source code is typically stored in a centralized repository so that all of your developers can collaborate on the same codebase. An SCM is software that can potentially be vulnerable the same as your first-party code. If an adversary gains access to your SCM through a vulnerability in the software or through social engineering then they will be able to manipulate your source code at the foundation.

    3. Developer environments

    Developer environments are powerful productivity tools for your engineers but they are another potential fount of risk for an organization. Most integrated developer environments come with a plug-in system so that developers can customize their workflows for maximum efficiency. These plug-in systems typically also have a marketplace associated with them. In the same way that a malicious Chrome browser plug-in and compromise a user’s laptop, a malicious developer plug-in can gain access to a “trusted” engineers development system and piggyback on this trusted access to manipulate the source code of an application.

    3rd-party dependencies (open source or otherwise)

    Third-party software is really just first-party software written by someone else. The same way that the cloud is just servers run by someone else. Third-party software dependencies are potentially vulnerable to all of the same risks associated with your own first-party code in the above section. Since it isn’t your code you have to deal with the risks in a different way. Below we lay out the two risks associated with this software supply chain risk:

    4. Known vulnerabilities (CVEs, etc)

    Known vulnerabilities are insecure or malicious code that has been identified in a third-party dependency. Typically the maintainer of a third-party dependency will fix their insecure code when they are notified and publish an update. Sometimes if the vulnerability isn’t a priority they won’t address it for a long time (if ever). If your developers rely on this dependency for your application then you have to assume the risk.

    5. Unknown vulnerabilities (zero-days)

    Unknown vulnerabilities are insecure or malicious code that hasn’t been discovered. These vulnerabilities can lay dormant in a codebase for months, years or even decades. When they are finally uncovered and announced there is typically a scramble across the world by any business that uses software (i.e. almost all businesses) to figure out whether they utilize this dependency and how to protect themselves from having it be exploited. Attackers are in a scramble themselves to determine who is using the vulnerable software and crafting exploits to take advantage of businesses that are slow to react.

    Build pipeline & artifact repository

    6. Build pipeline compromise

    A software build pipeline is a software system that pulls the original source code from an SCM then pulls all of the third-party dependencies from their source repositories and goes through the process of creating and optimizing the code into a binary that can then be stored in an artifact repository. It is similar to an SCM in that it is software, it is composed of both first- and third-party code which means there will be all of the same associated risks to its source code and software dependencies.
    Organizations deal with these risks differently than the developers of the build systems because they do not control this code. Instead, the risks are around managing who has access to the build system and what they can do with their access. Risks range from modifying where the build system is pulling source code from to modifying the build instructions to inject malicious or vulnerable code into previously secure sources.

    7. Artifact registry compromise

    An artifact registry is a centralized repository of the fully built applications (typically in the format of a container or image) that a deployment orchestrator would use to pull the software from to run it in a production environment. It is also software similar to a build pipeline or SCM and has the same associated risks as mentioned before.

    Typically, the risks of registries are managed through how trust is managed between the registry and the build system or any other system/person that has access to it. Risks range from an attacker poisoning the registry with an untrusted container or an attacker gaining privileged access to the repository and modifying a container in place.


    8. Deployment orchestrator compromises

    A deployment orchestrator is a system that pulls pre-built software binaries and runs the applications on servers. It is another type of software system similar to a build pipeline or SCM and has the same associated risks as mentioned before.

    Typically, the risks of orchestrators are managed through trust relationships between the orchestrator and the artifact registry or any other system/person that has access to it. Risks range from an attacker manipulating the orchestrator into deploying an untrusted container or an attacker gaining privileged access to the orchestrator and modifying a running container or manifest.

    9. Production environment compromise

    The production environment is the application running on a server that was deployed by an orchestrator. It is the software system built from the original source code that fulfills user’s requests. It is the final product that is created from the software supply chain. The risks associated with this system are different from most other systems because it typically serves users outside of the organization and has different risks associated with it because not as much is known about external users as internal users.

    Examples of software supply chain attacks

    As reliance on third-party components and open-source libraries grows, so does the potential for vulnerabilities in the software supply chain. Several notable incidents have exposed these risks, emphasizing the need for proactive security and a deep understanding of software dependencies. In this section, we explore significant software supply chain attacks and the lessons they impart.

    SolarWinds (2020)

    In one of the most sophisticated supply chain attacks, malicious actors compromised the update mechanism of SolarWinds’ Orion software. This breach allowed the attackers to distribute malware to approximately 18,000 customers. The attack had far-reaching consequences, affecting numerous government agencies, private companies, and critical infrastructure.

    Lessons Learned: The SolarWinds attack underscored the importance of securing software update mechanisms and highlighted the need for continuous monitoring and validation of software components.

    Log4j (2021)

    In late 2021, a critical vulnerability was discovered in the Log4j logging library, a widely used Java-based logging utility. Dubbed “Log4Shell,” this vulnerability allowed attackers to execute arbitrary code remotely, potentially gaining full control over vulnerable systems. Given the ubiquity of Log4j in various software applications, the potential impact was massive, prompting organizations worldwide to scramble for patches and mitigation strategies.

    Lessons Learned: The Log4j incident underscored the risks associated with ubiquitous open-source components. It highlighted the importance of proactive vulnerability management, rapid response to emerging threats, and the need for organizations to maintain an updated inventory of third-party components in their software stack.

    NotPetya (2017)

    Originating from a compromised software update mechanism of Ukrainian accounting software, NotPetya spread rapidly across the globe. Masquerading as ransomware, its primary intent was data destruction. Major corporations, including Maersk, FedEx, and Merck, faced disruptions, leading to financial losses amounting to billions.

    Lessons Learned: NotPetya highlighted the dangers of nation-state cyber warfare and the need for robust cybersecurity measures, even in seemingly unrelated software components.

    Node.js Packages coa and rc

    In July 2021, two widely-used npm packages, coa and rc, were compromised. Malicious versions of these packages were published to the npm registry, attempting to run a script to access sensitive information from users’ .npmrc files. The compromised versions were downloaded thousands of times before being identified and removed.

    Lessons Learned: This incident emphasized the vulnerabilities in open-source repositories and the importance of continuous monitoring of dependencies. It also highlighted the need for developers and organizations to verify the integrity of packages before installation and to be wary of unexpected package updates.

    JuiceStealer Malware

    JuiceStealer is a malware spread through a technique known as typosquatting on the PyPI (Python Package Index). Malicious packages were seeded on PyPI, intending to infect users with the JuiceStealer malware, designed to steal sensitive browser data. The attack involved a complex chain, including phishing emails to PyPI developers.

    Lessons Learned: JuiceStealer showcased the risks of typosquatting in package repositories and the importance of verifying package names and sources. It also underscored the need for repository maintainers to have robust security measures in place to detect and remove malicious packages promptly.

    Node.js Packages colors and faker

    In January 2022, the developer behind popular npm libraries colors and faker intentionally sabotaged both packages in an act of “protestware.” This move affected thousands of applications, leading to broken builds and potential security risks. The compromised versions were swiftly removed from the npm registry.

    Lessons Learned: This incident highlighted the potential risks associated with relying heavily on open-source libraries and the actions of individual developers. It underscored the importance of diversifying dependencies, having backup plans, and the need for the open-source community to address developer grievances constructively.

    Standards and best practices for preventing attacks

    There are a number of different initiatives to define best practices for software supply chain security. Organizations ranging from the National Institute of Standards and Technology (NIST) to the Cloud Native Computing Foundation (CNCF) to Open Source Security Foundation (OpenSSF) have created fantastically detailed documentation on their recommendations to achieve an optimally secure supply chain.

    Choosing any of the standards defined is better than choosing none or even cherry-picking from each of the standards to create a program that is best tailored to the risk profile of your organization. If you’d prefer to stick to one for simplicity’s sake and need some help deciding, Anchore has detailed our thoughts on the pros and cons of each software supply chain standard here.

    Below is a concise summary of each of the major standards to help get you started:

    National Institute of Standards and Technology (NIST)

    NIST has a few different standards that are worth noting. We’ve ordered them from the broadest to the most specific and, coincidently, chronically as well.

    NIST SP 800-53, “Security and Privacy Controls for Information Systems and Organizations”

    NIST 800-53, aka the Control Catalog, is the granddaddy of NIST security standards. It has had a long life and evolved alongside the security landscape. Typically paired with NIST 800-37, the Risk Management Framework or RMF, this pair of standards create a one-two punch that not only produce a highly secure environment for protecting classified and confidential information but set up organizations to more easily be compliant with federal compliance standards like FedRAMP.

    Software supply chain security (SSCS) topics first began filtering into NIST 800-53 in 2013 but it wasn’t until 2020 that the Control Catalog was updated to break out SSCS into its own section. If your concern is to get up and running with SCSS as quickly as possible then this standard will be overkill. If your goal is to build toward NIST 800-53 and FedRAMP compliance as well as build a secure software development process then this standard is for you. If you’re looking for something more specific, one of the two next standards might be for you.

    If you need a comprehensive guide to NIST 800-53 or its spiritual sibling, NIST 800-37, we have put together both. You can find a detailed but comprehensible guide to the Control Catalog here and the same plain english, deep-dive into NIST 800-37 here.

    NIST SP 800-161, “Cybersecurity Supply Chain Risk Management Practices for Systems and Organizations”

    NIST 800-161 is an interesting application of both the RMF and the Control Catalog for supply chain security specifically. The controls in NIST 800-161 take the base controls from NIST 800-53 and provide guidance on how to achieve more specific outcomes for the controls. For the framework, NIST 800-161 takes the generic RMF and creates a version that is tailored to SSCS.

    NIST 800-161 is a comprehensive standard that will guide your organization to create a development process with its primary output being highly secure software and systems.

    NIST SP 800-218, “Secure Software Development Framework (SSDF)”

    NIST 800-218, the SSDF, is an even more refined standard than NIST 800-161. The SSDF targets the software developer as the audience and gives even more tailored recommendations on how to create secure software systems.

    If you’re a developer attempting to build secure software that complies with all of these standards, we have an ongoing blog series that breaks down the individual controls that are part of the SSDF.

    NIST SP 800-204D, “Strategies for the Integration of Software Supply Chain Security in DevSecOps CI/CD Pipelines”

    Focused specifically on Cloud-native architectures and Continuous Integration/Continuous Delivery (CI/CD) pipelines, NIST 800-204D is a significantly more specific standard than any of the previous standards. That being said, if the primary insertion point for software supply chain security in your organization is via the DevOps team then this standard will have the greatest impact on your overall software supply chain security.

    Also, it is important to note that this standard is still a draft and will likely change as it is finalized.

    Open Source Security Foundation (OpenSSF)

    A project of the Linux Foundation, the Open Source Security Foundation is a cross-industry organization that focuses on the security of the open source ecosystem. Since most 3rd-party dependencies are open source they carry a lot of weight in the software supply chain security domain.

    Supply-chain Levels for Software Artifacts (SLSA)

    If an SBOM is an ingredients label for a product then the SLSA (pronounced ‘salsa’) is the food safety handling guidelines of the factory where they are produced. It focuses primarily on updating traditional DevOps workflows with signed attestations around the quality of the software that is produced.

    Google originally donated the framework and has been using an internal version of SLSA since 2013 which it requires for all of their production workloads.

    You can view the entire framework on its dedicated website here

    Secure Supply Chain Consumption Framework (S2C2F)

    The S2C2F is similar to SLSA but much broader in its scope. It gives recommendations around the security of the entire software supply chain using traditional security practices such as scanning for vulnerabilities. It touches on signed attestations but not at the same level of depth as the SLSA.

    The S2C2F was built and donated by Microsoft, where it has been used and refined internally since 2019.

    You can view the entire list of recommendations on its GitHub repository.

    Cloud Native Computing Foundation (CNCF)

    The CNCF is also a project of the Linux Foundation but is focused on the entire ecosystem of open-source, cloud-native software. The Security Technical Advisory Group at the CNCF has a vested interest in supply chain security because the majority of the software that is incubated and matured at the CNCF is part of the software development lifecycle.

    Software Supply Chain Best Practices White Paper

    The Security Technical Advisory Group at CNCF created a best practices white paper that was heralded as a huge step forward for the security of software supply chains. The document creation was led by the CTO of Docker and the Chief Open Source Officer at Isovalent. It captures over 50 recommended practices to secure the software supply chain.

    You can view the full document here.

    Types of Supply Chain Compromise

    This document isn’t a standard or best practices, instead it is support for the best practices white paper that defines a full list of supply chain compromises.

    Catalog of Supply Chain Compromises

    This isn’t a standard or best practices document, as well. It is instead a detailed history of the significant supply chain breaches that have occurred over the years. Helpful for understanding this history that informed the best practices detailed in the accompanying white paper.

    For help managing and maintaining best practices, consider adopting a software supply chain management platform.

    How Anchore can help

    Anchore is a leading software supply chain security company that has built a modern, SBOM-powered software composition analysis (SCA) platform that helps organizations incorporate many of the software supply chain best practices that are defined in the above guides.

    As we have learned working with Fortune 100 enterprises and federal agencies, including the Department of Defense, an organization’s supply chain security can only be as good as the depth of the data on their supply chain and the automation of processing the raw data into actionable insights. Anchore Enterprise provides an end-to-end software supply chain security system with total visibility, deep inspection, automated enforcement, expedited remediation and trusted reporting to deliver actionable insights to make a supply chain as secure as possible.

    If you’d like to learn more about the Anchore Enterprise platform or speak with a member of our team, feel free to book a time to speak with one of our specialists.

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