How should security teams reduce email phishing risk when users still need access to business systems and data?

Why This Matters for Security Teams

Email phishing is not just a user-awareness problem. It is an identity problem, because the attacker’s real objective is often to turn a message into valid access to business systems, shared data, and downstream approvals. When users still need to open mail, click links, and authenticate to cloud apps, security teams have to reduce the value of stolen credentials and make abuse harder to operationalise. That means phishing-resistant MFA, strong session controls, and email filtering need to work together with identity governance.

NHIMG research shows the pattern is broader than inbox hygiene alone: in The State of Non-Human Identity Security, 85% of organisations lack full visibility into third-party vendors connected via OAuth apps. That matters because email-delivered attacks increasingly pivot into token abuse, consent abuse, and over-permissioned access rather than only password theft. Guidance from NIST Cybersecurity Framework 2.0 reinforces that identity, detection, and response must be coordinated rather than treated as separate controls.

In practice, many security teams encounter phishing as a business-impacting identity compromise only after a mailbox rule, OAuth grant, or help desk reset has already been abused.

How It Works in Practice

The most effective approach is layered and assumes that some malicious email will reach users. Start by making stolen passwords less useful. Phishing-resistant MFA, preferably with passkeys or hardware-backed methods, reduces the chance that a fake login page can be used to replay credentials. Where possible, move high-risk users and administrators to passwordless authentication and stronger device-bound sessions. That aligns with current guidance in NIST SP 800-53 Rev. 5 Security and Privacy Controls, especially controls tied to identification, authentication, and access enforcement.

Next, reduce the email attack surface itself. Mail filtering should block spoofing, malicious attachments, and suspicious links before they reach the inbox. Link inspection is useful, but it is not enough on its own because many phishing campaigns now rely on legitimate infrastructure, QR codes, or consent flows. Teams should also monitor for mailbox rule abuse, suspicious forwarding, and OAuth grants that extend access beyond the inbox. This is where NHI hygiene intersects with human phishing defence, as described in Ultimate Guide to NHIs.

• Use phishing-resistant MFA for email, VPN, and business-critical SaaS.
• Restrict legacy authentication and disable weak recovery paths where possible.
• Inspect OAuth consent, forwarding rules, and app permissions continuously.
• Build a simple report-and-contain workflow so users can escalate quickly.
• Contain suspected accounts by revoking sessions, tokens, and recent grants.

User training still matters, but it should focus on recognition plus reporting, not perfect detection. The best programs make reporting frictionless and response fast, because delay gives attackers time to register devices, create rules, or exfiltrate data. These controls tend to break down in heavily delegated SaaS environments because business users can approve broad app access faster than security teams can review it.

Common Variations and Edge Cases

Tighter authentication often increases user friction, requiring organisations to balance phishing resistance against support load and workflow speed. That tradeoff becomes sharper in environments with contractors, frontline workers, and shared systems, where universal hardware keys or strict device binding may not be practical. Current guidance suggests using risk-based policy rather than one-size-fits-all controls, but there is no universal standard for every workforce model yet.

Some environments need extra protection around recovery and delegation. If a phishing campaign targets help desks, backup codes, account resets, and MFA re-enrolment become high-value paths. If users work through browser-only SaaS, session hijacking and token theft can be as damaging as password theft, so session lifetime and device trust matter. For organisations dealing with third-party access and SaaS integrations, NHIMG’s 52 NHI Breaches Analysis and the OWASP Non-Human Identity Top 10 both point to the same practical lesson: once identity tokens are abused, inbox controls alone are too late.

That is why mature programs treat phishing defence as an identity and token containment problem, not only a messaging problem.

Related resources from NHI Mgmt Group

• How should security teams reduce phishing risk in high-value access paths?
• How should security teams reduce phishing risk without frustrating users?
• How should security teams reduce open access risk in data governance programmes?
• How should security teams use data classification to reduce access risk?