In cybersecurity, we often frame our defensive strategies around the people, process, and technology “triad”. It’s a clean conceptual model that helps organizations structure their security programs and allocate resources. However, this framework becomes more complex when we consider that modern organizations don’t operate in isolation. They exist within an intricate web of third-party relationships that can introduce vulnerabilities across all three domains.

The manifestations of third-party risks extend beyond the digital realm. History offers important and significant examples of supply chain compromises affecting the physical world. The Great Seal bug, planted in the US embassy in Moscow in 1945, demonstrated how adversaries could compromise physical objects to achieve intelligence objectives. More recently, we’ve witnessed explosive components targeting drone operator equipment in the Russo-Ukrainian conflict, and the 2024 Lebanon electronic device attacks. These three attacks were all used in physical world conflicts to give the attacking side a significant advantage.

The software realm presents equally compelling examples. The CodeCov breach in 2021 exemplified how a single compromised development tool could provide attackers with unprecedented access to customer environments. SolarWinds became synonymous with supply chain attacks, demonstrating how trusted software updates could become vectors for nation-state espionage. Even seemingly mundane components can harbor threats — we’ve seen legitimate software packages compromised with cryptocurrency miners, turning enterprise infrastructure into unwitting participants in mining operations.

But third-party risks aren’t limited to compromised code or hardware. Vendor relationships themselves create attack surfaces. Managed service providers and law firms - with all the data and information that they normally handle for their customers - have become attractive pivot points for adversaries seeking access to their ultimate targets. When a vendor falls victim to compromise, every organization in their ecosystem becomes potentially exposed. This interconnectedness means that an organization’s security posture is only as strong as its weakest vendor relationship.

The actors behind these campaigns are frequently nation-states with substantial resources and patience. They understand that targeting a single vendor can yield access to dozens or hundreds of “downstream” victims. It’s an efficient approach that leverages the trust relationships inherent in business partnerships.

What enables these attacks to succeed? Often, it’s the absence of formal vendor management processes and comprehensive risk assessments. The phenomenon of “shadow IT” compounds this challenge — as organizations embrace agility and decentralized decision-making, individual teams may engage with vendors without central oversight. Software development teams face similar challenges when dependency tracking falls short, creating blind spots in the supply chain.

However, organizations aren’t powerless against these threats. Effective threat modeling forms the foundation of third-party risk management — understanding what data you cannot afford to lose helps prioritize vendor relationships and security controls. Formal risk management processes, supported by comprehensive risk registers, provide visibility into the vendor ecosystem and enable informed decision-making.

For software-centric organizations, maintaining visibility into build pipelines and dependency chains becomes critical. Vendor management processes should include security-focused onboarding procedures. Even organizations without resources for formal risk assessments can establish baseline security expectations and require vendors to demonstrate their security posture.

The principle of least privilege applies not just to internal systems but to vendor relationships as well. Limiting vendor access to only what’s necessary for their function reduces potential exposure. Some organizations are also exploring how threat intelligence can provide early warning of vendor compromises, though this approach requires maturity in both consumption of intelligence and incident response.

Third-party risks represent one of the most challenging aspects of modern cybersecurity precisely because they exist at the intersection of trust, business necessity, and technological complexity. While we cannot eliminate these risks entirely, acknowledging their pervasive nature across people, process, and technology domains that extends well beyond organizational boundaries is the first step toward managing them effectively.