What is a SPOF?

In today’s interconnected digital environment, a single weak link can threaten the entire chain. A SPOF refers to any individual component (hardware, software, vendor, or service) which, if compromised or disrupted, could disrupt critical operations. Within the federal healthcare environment, these vulnerabilities can have life-threatening consequences.

SPOFs are especially relevant for Information System Security Officers (ISSO) tasked with securing the systems that support everything from electronic health records (EHRs) to payment processing. 

The 2024 cyberattack on Change Healthcare revealed just how damaging the failure of a dominant technology supplier can be. With cyber adversaries targeting systemic vulnerabilities, it’s time for federal ISSOs to build resilience by addressing SPOFs head-on.

Why SPOFs matter to ISSOs at CMS

Federal civilian agencies like CMS rely on intricate webs of interconnected vendors and technologies to operate. SPOFs undermine the very systems ISSOs are entrusted to protect. From cloud-based infrastructure and network identity management to claims processing and health information exchanges, federal systems can be over-reliant on specific third-party providers.

This reliance can be risky when a vendor holds a dominant share of a particular service area. The risk is compounded when the service is integral to public health or financial operations. Assessing and addressing these dependencies is part of ISSO’s core responsibilities within the Risk Management Framework (RMF).

Real-world case study

In February 2024, Change Healthcare, the nation’s largest processor of medical claims, fell victim to a ransomware attack launched by the hacker group, ALPHV/BlackCat. The attackers exploited a remote access server lacking multi-factor authentication (MFA). This impacted claims processing systems across the country, disrupting the work of hospitals, pharmacies, and insurers.

The breach exposed a core SPOF in the healthcare IT supply chain: overreliance on a single clearinghouse. Hospitals reported daily revenue losses exceeding $1 million, and providers scrambled to implement manual workarounds. The protected health information (PHI) of over 100 million Americans was compromised. For ISSOs, the lessons are clear: high-functioning systems with no backup are not resilient systems.

Identifying SPOFs in federal IT environments

The first step to avoiding SPOFs is knowing where they are. ISSOs can follow these steps to identify SPOFs:

Inventory all systems, hardware, software, and services. Modern asset management tools can catalog these resources and reveal which functions depend on which components.

Use dependency mapping to visualize the flow of information and system reliance. Identify components with no redundancy or practical alternatives. Apply National Institute of Standards and Technology (NIST) standards such as SP 800-30 (Risk Assessment) and Federal Information Processing Standards FIPS 199 (System Impact Categorization) to assess criticality.

Leverage Software and Hardware Bills of Materials to better understand third-party components embedded in your systems. A Software Bill of Materials (SBOM) identifies all software components - open source, commercial, and proprietary - used in an application, while a hardware Bill of Materials (HBOM) maps physical components and their manufacturing origins. These BOMs are essentially “asset inventories,” providing visibility into embedded dependencies which are often overlooked, such as libraries, firmware, or chips sourced from high-risk vendors. 

For ISSOs, requiring SBOMs and HBOMs during acquisition and throughout continuous monitoring can reveal hidden vulnerabilities, support patch management, and inform risk decisions related to foreign influence or unsupported software. Many vendors can provide SBOMs upon request.

Mitigation strategies for SPOFs

After identifying SPOFs, the next step is to mitigate them. Start with vendor diversification where possible: avoid relying solely on a single supplier for mission-critical services. For example, use multiple cloud regions or failover providers to distribute operational risk.

Procurement teams can take the following steps:

• Incorporate cybersecurity requirements such as Secure Software Development framework (NIST SP 800-218)
• Demand SBOMs and HBOMs in contracts
• Implement architectural redundancy (backups, isolated environments, and alternate access methods for essential platforms)

Continuous monitoring tools and threat intelligence sharing, like those offered through the Health Information Sharing and Analysis Center (H-ISAC),  alert ISSOs to new risks affecting known SPOFs.

Mapping systemic risks: the HHS-led SPOF initiative

The U.S. Department of Health and Human Services (HHS) is leading a national effort to map SPOFs across the healthcare technology landscape. In coordination with stakeholders like the Health Sector Coordinating Council (HSCC) and Health Information Sharing and Analysis Center (H-ISAC), the initiative seeks to identify vendor and service dependencies posing outsized risks to public health and safety., the initiative seeks to identify vendor and service dependencies posing outsized risks to public health and safety.

While the specific mapping data remains internal, the approach underscores the need for transparency and collaboration. ISSOs are encouraged to support these efforts and adopt similar methodologies to evaluate internal risks within their agencies.

Recommendations

ISSOs manage cyber supply chain risk effectively when they move beyond perimeter cybersecurity and embrace systemic resilience. This begins with: 

• Identifying SPOFs
• Evaluating their potential impact
• Implementing mitigation strategies such as diversification, secure procurement, and redundancy

CMS and other federal agencies depend on ISSOs to proactively guard against hidden vulnerabilities in the digital infrastructure. By understanding and avoiding SPOFs, ISSOs can support continuity, uphold security mandates, and protect the public trust.

Summary of applicable NIST/CISA guidance documents 

The following resources from the NIST and the Cybersecurity Infrastructure Security Agency (CISA) form the policy backbone of effective SPOF and supply chain risk mitigation strategies. ISSOs can build tailored checklists and assessment protocols using these documents as a foundation.

NIST SP 800-30 Rev. 1 – Guide for Conducting Risk Assessments

o   Purpose: Structured methods for identifying threats, vulnerabilities, and impacts.

o   Implementation tip: Use this to develop risk heatmaps for critical services and vendors. Update risk assessments annually or when introducing new technologies.

NIST SP 800-161 Rev. 1 – Cybersecurity Supply Chain Risk Management Practices for Systems and Organizations

o   Purpose: A comprehensive framework for integrating SCRM into organizational policies and the RMF.

o   Implementation tip: Align CMS acquisition planning and vendor onboarding with the controls and processes described in this document. Include supplier assurance activities in system security plans.

NIST SP 800-218A – Secure Software Development Framework (SSDF)

o   Purpose: Establishes secure coding and supply chain integrity standards across the software lifecycle.

o   Implementation tip: Mandate SSDF compliance for all CMS contractors developing or modifying code. Embed secure development checkpoints into agile workflows.

NIST FIPS 199 – Standards for Security Categorization of Federal Information and Information Systems

o   Purpose: Determine impact levels (low, moderate, high) for confidentiality, integrity, and availability.

o   Implementation tip: Use FIPS 199 categories to classify systems. High-impact systems should receive additional scrutiny for SPOFs and single-vendor dependencies.

CISA HBOM Framework – Hardware Bill of Materials Guidance

o   Purpose: Promotes visibility into component-level sourcing and hardware integrity.

o   Implementation tip: Require HBOMs in IT hardware procurement contracts. Integrate HBOM data into system security assessments to identify foreign-sourced components or proprietary monopolies.

Executive Order 14028 – Improving the Nation’s Cybersecurity

o   Purpose: Directs federal agencies to enhance software transparency, implement Zero Trust architecture, and secure software supply chains.

o   Implementation tip: Establish agency-level policies requiring SBOMs, threat intelligence sharing, and vendor cyber hygiene evaluations in alignment with EO 14028.

About the author: Michael “Hobie” Hobert supports the CMS Office of Information Technology / IT Security & Privacy Group (OIT/ISPG) Division of Strategic Information (DSI), applying his broad experience in healthcare, technology, and banking to expand security awareness at CMS. 

Expert contributions: DSI SCRM team members Kimberly Crichlow, Michael Eddi, and Crystal Tennessee.