How should law firms govern third-party vendor access without blocking operations?

Why This Matters for Security Teams

Third-party vendor access is one of the most common places where operational convenience quietly outruns control. Law firms need vendors for document systems, e-discovery platforms, billing tools, and managed infrastructure, but those same connections can become durable backdoors if they are not tied to a specific task. NHI Mgmt Group notes that 92% of organisations expose NHIs to third parties, which makes supply chain access a routine governance issue rather than an edge case. The practical question is not whether vendors need access, but whether the firm can prove why that access exists and when it should disappear.

For legal environments, the risk is amplified by confidentiality duties, matter segregation, and regulatory scrutiny. Best practice is evolving toward purpose-bound access, short-lived credentials, and session-level attribution aligned with guidance such as the OWASP Non-Human Identity Top 10 and the NIST Cybersecurity Framework 2.0. That framing keeps operations moving while reducing the chance that a vendor account outlives the work it was meant to support. In practice, many security teams encounter overbroad vendor access only after a support escalation, audit finding, or incident response exercise exposes how much privilege had been left in place.

How It Works in Practice

Effective governance starts by treating vendor access as a set of controlled service relationships, not as a standing user population. Each vendor should be mapped to a business owner, a specific system, and a limited purpose. Access should be issued only when the request is tied to an approved task, and the entitlement should expire automatically when the task closes. That is the operational difference between a permanent exception and a controlled exception.

In practice, firms usually combine several controls:

• Just-in-time access approvals for each case, matter, or support event.
• Short-lived credentials or session tokens instead of shared passwords.
• Session recording and command attribution for high-risk administrative activity.
• Scoped entitlements that allow only the minimum application, data set, and time window needed.
• Automated offboarding so access is revoked when the contract, ticket, or engagement ends.

The Ultimate Guide to NHIs is clear that offboarding and revocation remain weak points across enterprises, which is why manual cleanup is not enough for vendor access. A good operating model also distinguishes between interactive support accounts, API integrations, and machine-to-machine service identities, because each one needs different controls even when the vendor is the same. Where possible, firms should align this with Zero Trust principles and insist on auditable proof of identity, not just a username and password. More detailed lifecycle guidance is available in the Lifecycle Processes for Managing NHIs section of the guide. These controls tend to break down when vendors insist on shared admin accounts, legacy remote-support tools, or undocumented emergency access paths because those environments resist fine-grained attribution and automated expiry.

Common Variations and Edge Cases

Tighter vendor access often increases onboarding time and coordination overhead, requiring firms to balance speed against defensibility. That tradeoff is real, especially when support is needed during hearings, filing deadlines, or incident containment. The goal is not to make access frictionless, but to make the friction predictable, approved, and reversible.

There is no universal standard for this yet, but current guidance suggests three common edge cases deserve special handling. First, “break-glass” access should be isolated, heavily logged, and reviewed immediately after use. Second, vendors supporting multiple clients should never reuse the same privileged path across firms, because cross-tenant access creates unnecessary exposure. Third, long-lived integrations that cannot be redesigned immediately should be placed under compensating controls such as vaulting, stronger monitoring, and periodic recertification. The 52 NHI Breaches Analysis shows how often identity failures become breach paths, and that lesson applies directly to vendor accounts that are convenient but opaque. For firms building a formal program, the Regulatory and Audit Perspectives section is especially useful for translating access controls into evidence. The strongest programs do not eliminate vendor access; they make it explainable, time-bound, and easy to remove without disrupting legal work.

Related resources from NHI Mgmt Group

• How should security teams govern third-party remote access in practice?
• How should teams govern third-party access in digital healthcare environments?
• How should security teams govern vendor access across the third-party lifecycle?
• How should organisations govern third-party access in a vendor risk policy?