Rethinking The Supply Chain Risk You Can’t Ignore: Third-Party Access

• The percentage of breaches that involved a third-party doubled in the last year, and 54% of firms were hit by a third-party sourced attack or breach; vendor access is now a top enterprise risk.^{1, 2}

• Traditional, siloed identity and access management (IAM) tools weren’t built to handle the scale, diversity, or fluidity of modern B2B ecosystems and supply chains.

• Identity gaps, like stale accounts, overpermissioned access, and weak onboarding, create openings for fraud and data exfiltration.

• B2B IAM enables continuous, adaptive trust to govern external access, reducing risk and improving third-party collaboration.

Businesses depend on a vast network of third-party organizations to drive innovation, speed, and scale in today’s hyper-connected economy. But behind that collaboration lies a critical security question: Can you trust every connection?

The truth is, while your internal security practices may be sound, the weakest point in your defense might lie just outside your organizational boundary — in your supply chain.

According to the 2025 Verizon Data Breach Investigations Report, 30% of all breaches they analyzed were linked to third-party involvement. Recent research from CyberRisk Alliance found that 54% of organizations have experienced a third-party security breach, and SecurityScorecard research unearthed that 98% work with at least one vendor that has been breached in the last two years.³ These are not theoretical risks — they’re operational realities that security teams are facing every day.

Consider the 2023 MOVEit breach, a high-profile example where a zero-day exploit ultimately impacted over 2,600 organizations and 77 million people, including government agencies, healthcare providers, and financial institutions.⁴ While the initial compromise exploited a software vulnerability, the breach spread through the extended vendor ecosystem, exposing data across thousands of interconnected businesses. For many affected organizations, the real challenge wasn’t the exploit itself, it was the inability to quickly answer basic questions like: Which partners had access to our systems? What data could they reach? And, who owns those access paths?

This is where identity becomes the control point. When third-party access isn’t governed — when service accounts are unmonitored, user credentials are over-permissioned, or integrations go unaudited — a single point of compromise can ripple across an entire supply chain. That’s not just a software flaw problem. That’s a visibility and governance problem — exactly the type of risk modern B2B IAM is designed to solve.

Today’s supply chains are digital, dynamic, and often built on thousands of external identities outside your control. Contractors, technology providers, logistics firms, resellers, and vendors regularly require direct access to your enterprise systems, applications, or sensitive data. However, when identity and access isn’t managed with a modern B2B IAM approach providing sufficient oversight, discipline and transparency, those external identities can quickly become open invitations for threat actors, creating serious vulnerabilities across your digital ecosystem.

Third-party access is one of the fastest-growing sources of enterprise risk. Traditional identity management approaches weren’t designed for the complexity and dynamism of modern supply chains. The result is a rapidly growing set of vulnerabilities that threat actors are actively exploiting.

Some of the most common threats include:

• Unverified onboarding, where third-party users are granted access with little or no identity verification, opening the door to deepfakes and fraud.

• Credential sharing within partner organizations, making it difficult to attribute actions to a specific individual and increasing the likelihood of credential theft or misuse.

• Excessive access that goes unreviewed over time, often granting users more privileges than necessary and undermining the principle of least-privilege.

• Orphaned accounts that remain active after a partnership ends or a user becomes inactive, providing a silent and persistent risk vector.

• Limited visibility into third-party activity increases compliance and regulatory risk by making it difficult to detect unauthorized access, enforce security policies, and demonstrate adherence to data protection requirements.

These gaps create a perfect storm for fraud, attacks, and data breaches, while severely constraining an organization’s ability to enforce consistent access policies across its vendor ecosystem.

Most breaches today don’t begin with sophisticated malware, they start with human error. In fact, according to the 2024 Verizon Data Breach Investigations Report, 68% of breaches involve a human element, such as compromised credentials, misused identities, or access that was granted too broadly and revoked too late. Vendors and suppliers frequently use shared accounts or weak authentication mechanisms that make impersonation easier.⁵ Stale accounts often persist long after relationships end, creating lingering backdoors into critical systems. Even active partners are rarely monitored for behavioral anomalies once inside the environment.

Unfortunately, the risk isn’t limited to external actors. Fraud can emerge from within partner organizations — a contractor misusing elevated access, or a supplier exploiting weak oversight to retrieve sensitive information. Without continuous verification, user and entity behavior analytics (UEBA), or adaptive controls, these risks often stay hidden until it’s too late.

In a landscape where fraud and account takeover are on the rise, organizations can no longer treat access as a static entitlement. Identity must be continuously evaluated — with access decisions dynamically informed by user behavior, context, and evolving risk.

Many security and IAM leaders understand the need for stronger access controls, but implementing them in a supply chain environment is far from straightforward. The challenge isn’t just the volume of third-party users; it’s the diversity of those partners and how they operate. Different vendors have different maturity levels, IT infrastructures, and security capabilities. Some partners may use federated identity systems, while others may rely on spreadsheets and email.

This complexity leads to fragmented identity data, inconsistent provisioning practices, and reliance on manual approvals or ticket-based access models. Traditional IAM tools, built for employee directories and static role assignments, weren’t designed to manage the messy realities of B2B relationships, and they’re struggling to keep up.

As a result, organizations often fall back on manual processes and ad hoc governance. This leads to inconsistency, and most organizations are left with a patchwork of workflows and a lack of centralized visibility.

Who has access? What systems can they reach? How is their behavior monitored? Too often, there are no clear answers, and that lack of consistency and control is where risk thrives. Supply chain security isn’t just difficult because of outside actors. It’s difficult because traditional tools weren’t built for the shared trust model that defines today’s partner ecosystems.

This shift to trust that is earned, verified, and continuously reinforced is exactly what modern B2B IAM is designed to support.

True B2B IAM enables organizations to verify users at onboarding — not just with a name and password, but with identity proofing workflows that ensure legitimacy and establish trust from the start. It supports federated single sign-on (SSO), allowing partner users to authenticate through their home organization’s identity provider while still being governed by your access policies. This improves user experience (UX), reduces credential sprawl, and strengthens overall security.

B2B IAM also supports delegated administration models that allow partners to manage their users within clearly defined boundaries, reducing friction and IT overhead without giving up oversight. It applies relationship-based access models and enforces strong, adaptive authentication and real-time access decisions based on roles, behavior, and contextual risk, ensuring that access aligns with business needs and how your partners operate, not just broad permissions.

Perhaps most importantly, B2B IAM enables continuous trust. It empowers organizations to continually certify access, monitor access patterns, flag unusual behavior, and escalate assurance when something feels off. Instead of assuming trust will remain valid indefinitely, it treats identity as a signal to be evaluated moment by moment, allowing organizations to truly trust every digital moment, not just the first interaction.

This is what turns third-party access from a vulnerability into a source of resilience and transforms supply chain security from a pain point into a competitive differentiator, enabling faster collaboration, stronger compliance, and a consistent security posture across your ecosystem.

To build resilience into your third-party identity strategy, consider these foundational practices:

• Verify third-party identities at onboarding.
  Ensure every external user is who they claim to be before granting access. Use identity proofing techniques tailored to user risk profiles and revalidate when trust signals change.

• Enforce Zero Trust principles with dynamic controls.
  Verify access explicitly by aligning access to business roles, relationships, and current context. Use attribute-based and policy-based access controls and real-time risk signals to keep permissions aligned with risk and to prevent unnecessary exposure.

• Apply phishing-resistant MFA for all third-party identities.
  Passwords and SMS codes are not enough. Avoid shared logins or weak second factors. Require stronger multi-factor authentication (MFA) for all third-party access, especially where sensitive data or systems are involved.

• Support federated SSO for seamless, governed access.
  Allow partner users to authenticate using their own trusted identity provider, while still enforcing your organization’s access policies. This reduces credential sprawl, simplifies the UX, and maintains policy-driven control across organizational boundaries.

• Delegate access management with built-in guardrails.
  Let trusted partners manage their own users within defined policy constraints. Maintain centralized visibility and enforce auditability to reduce operational burden without compromising security.

• Automate user lifecycle and offboarding.
  Orphaned accounts are a major security liability. Automatically revoke access when a user leaves, their role changes, users become inactive, or a partnership ends.

• Continuously evaluate behavior to detect anomalies and increase assurance.
  Fraud doesn’t wait for access reviews. Monitor user behavior and context in real time to detect outliers, elevate verification when needed, and restrict access when trust erodes.

• Maintain a clear audit trail and support continuous certification.
  Every access grant, modification, and login should be logged. Implement periodic and event-driven access reviews to prevent entitlement creep and support compliance.

These practices help organizations shift from reactive access control to proactive trust assurance — critical for building supply chains that are not just connected, but secure.

Your third-parties aren’t inherently the weakest link in your security strategy, but without a strong identity foundation, their access, and your ability to govern it, absolutely is.

With the right B2B IAM strategy, you’re not just managing complexity, you're transforming third-party access from a source of risk into a foundation of verifiable, enforceable trust. It enables you to scale relationships with confidence, apply consistent security controls, and adapt in real time — no matter how dynamic your supply chain becomes.

In a world where every digital interaction matters, identity isn’t just a part of supply chain security, it is your first and best defense. When you can trust every identity, you can trust every connection, because every digital moment is backed by visibility, governance, and accountability.

¹ Verizon 2025 Data Breach Investigations Report.

² CyberRisk Alliance, 2024, “From Trust To Security: Third-Party risk management strategies and challenges.”

³ Cyentia Institute and SecurityScorecard, February 2023. “Research Report: Close Encounters of the Third (and Fourth) Party Kind.”

⁴ Gagandeep Kaur, CSO Online, November 21, 2023, "MOVEit carnage continues with over 2600 organizations and 77M people impacted so far.

⁵ Verizon 2024 Data Breach Investigations Report.