Email security is shifting beyond secure email gateways

At a glance

What this is: This on-demand webinar argues that modern email threats are outpacing legacy secure email gateways and that Microsoft plus Abnormal is being used to close that gap.

Why it matters: It matters because email remains a primary identity attack path, and IAM teams must account for how phishing, account takeover, and email-borne threats intersect with human and non-human access.

👉 Watch Abnormal AI's on-demand webinar on replacing secure email gateways

Context

Traditional secure email gateways were built to filter known bad content at the perimeter, but modern email attacks often rely on convincing content, compromised accounts, and behavior that only becomes suspicious after delivery. That makes email security a governance problem as much as a detection problem, because identity, access, and user behavior all sit on the attack path.

For IAM, PAM, and security operations teams, the question is not whether email controls exist, but whether they still match current attacker behavior. When adversaries use identity-driven phishing, session abuse, and business email compromise, the defensive model must connect messaging security to identity assurance, detection, and response rather than treating email as a standalone channel.

Key questions

Q: How should security teams handle email threats that bypass secure email gateways?

A: Teams should treat bypass as a signal that perimeter filtering is no longer enough. The response should combine behavioral detection, mailbox telemetry, and identity controls so phishing, impersonation, and account takeover are handled as one risk chain rather than as separate email and IAM problems.

Q: Why do email attacks often become identity incidents?

A: Email attacks become identity incidents when the goal is credential theft, session abuse, or unauthorized workflow action. Once a message can trigger account access or privileged business actions, the compromise is no longer only about content delivery. It is about who can act inside the organization.

Q: How can organizations tell whether email defenses are keeping up?

A: Look for controls that detect suspicious sender behavior, abnormal reply paths, and compromised-account activity, not just malicious attachments or links. If the program cannot connect an email alert to access risk, incident response will stay fragmented and attackers will keep using trusted communication paths.

Q: What is the difference between perimeter email filtering and behavioral email security?

A: Perimeter filtering focuses on content, reputation, and obvious malicious indicators. Behavioral email security looks at how messages, senders, and users behave over time, which helps catch impersonation, compromised accounts, and low-signal attacks that do not look malicious at delivery.

Background and context

Why legacy secure email gateways miss modern threats

Secure email gateways are strongest when attacks are visible through signatures, reputation, or obvious malicious links. They struggle when an attacker uses trusted domains, compromised senders, or convincing social engineering that looks legitimate at delivery time. Modern email threats increasingly rely on context rather than payload, so static filtering alone cannot reliably separate malicious from legitimate messages. AI-assisted detection changes the model by looking at message patterns, sender behavior, and anomalous interaction paths rather than just content inspection.

Practical implication: security teams should evaluate whether their email stack can detect contextual abuse, not just block known-bad indicators.

How Microsoft plus Abnormal changes email defense operations

The operational shift described in the webinar is not just about adding another detection layer. It is about combining platform-native identity and mailbox telemetry with behavioral analysis so the security team can see anomalies across the email lifecycle. That matters because modern attacks often span delivery, user interaction, and follow-on abuse of accounts or workflows. The value is less about a single control and more about reducing the number of disconnected tools operators need to watch during incident handling.

Practical implication: security operations teams should map which alerts can be consolidated without losing visibility into identity-linked email abuse.

Why email security now sits inside identity governance

Email compromise is no longer only an inbox problem. It is an identity problem because phishing, impersonation, and malicious replies often aim to capture credentials, redirect funds, or create unauthorized access paths. That makes email security part of the same control plane as authentication, access reviews, and privileged account protection. When email threats are treated separately from identity governance, organizations miss the link between message-level compromise and downstream account abuse.

Practical implication: IAM and SOC teams should coordinate controls for phishing, account takeover, and privileged access rather than managing them in separate workstreams.

NHI Mgmt Group analysis

Legacy email perimeter controls are no longer aligned to how identity-driven attacks actually work. The problem is not only that threats are more sophisticated, but that the control model was built around filtering content rather than understanding trust, behavior, and downstream identity abuse. Once attackers use convincing messages and legitimate-looking workflows, the secure email gateway becomes a narrow checkpoint instead of a meaningful governance layer. Practitioners should treat email security as part of identity protection, not a separate inbox-only problem.

Email security has become a human identity governance issue with NHI spillover. Compromised mailboxes, forged requests, and business process abuse frequently lead to credential theft, token misuse, or delegated access that reaches beyond the original user. That means the boundary between human identity and non-human access is already porous in many enterprises. Teams that do not connect email controls to access governance will keep missing the chain from message compromise to privilege abuse.

Behavioral detection is the named concept that explains why the shift away from SEGs is happening. The real security gap is not just payload inspection, but the inability to judge whether a message, sender, or interaction sequence fits normal organizational behavior. AI-based analysis works because it shifts the focus from content alone to context and anomaly. Practitioners should assess their email stack on whether it can see trust abuse, not just obvious malicious artifacts.

Email security modernization will increasingly be judged by operational simplification, not tool count. The webinar’s core signal is that security teams are under pressure to reduce complexity while improving threat coverage. That is a governance issue because fragmented email controls create blind spots between detection, response, and identity remediation. The practical test is whether the program can shorten time-to-detect and time-to-contain without multiplying consoles and exceptions.

For IAM leaders, email compromise should be measured as an access risk, not only a messaging risk. If an email event can trigger password resets, session hijacking, payment diversion, or privileged workflow abuse, then it belongs in the identity control conversation. That changes who owns the problem, which metrics matter, and how incidents are triaged. Practitioners should build joint operating procedures across IAM, SOC, and email security teams.

From our research:

• 85% of organisations lack full visibility into third-party vendors connected via OAuth apps, according to The State of Non-Human Identity Security.
• A further 47% have only partial visibility into those OAuth-connected vendors, which leaves most organisations unable to assess downstream trust chains with confidence.
• For a broader lifecycle and governance lens, Top 10 NHI Issues shows why visibility gaps, over-privilege, and weak monitoring keep recurring across machine access programmes.

What this signals

Behavioral email defense is becoming a baseline expectation, not an advanced feature. Legacy filtering will keep missing attacks that exploit trust, timing, and compromised identities. Teams should prepare for a governance model where message risk and access risk are reviewed together, especially where mailboxes can trigger financial, administrative, or privileged actions.

As email security converges with identity governance, the operating model will need tighter handoffs between SOC, IAM, and PAM teams. That includes faster account containment, clearer ownership for mailbox compromise, and better evidence collection when a message becomes the first step in an access incident.

The practical test for practitioners is whether they can see email compromise as part of the same attack surface as credentials and access tokens. If they cannot, the organisation will continue to detect the message but miss the identity consequence.

For practitioners

• Map email compromise to identity impact paths Trace how phishing, impersonation, and mailbox takeover can lead to credential theft, reset abuse, or privileged workflow manipulation. Use those paths to determine which email alerts need IAM and SOC escalation, not just inbox quarantine.
• Test whether your stack detects behavioral abuse Validate whether controls can flag anomalous sender behavior, message timing, unusual reply chains, and suspicious user interactions rather than only known-bad links or attachments. Use realistic business email compromise scenarios in testing.
• Align email security with access governance Create shared incident playbooks for mailbox compromise, token theft, and account takeover so identity remediation happens alongside email containment. Include privileged accounts and delegated mail access in the same review cycle.
• Reduce control fragmentation across the email stack Identify which detections, response steps, and administrative tasks can be consolidated so operators are not switching between disconnected tools during an active investigation. Measure the result in fewer manual handoffs and faster containment.

Key takeaways

• Secure email gateways alone are no longer sufficient when attackers use trusted-looking messages and identity abuse instead of obvious malicious payloads.
• The business impact of email compromise now extends into credential theft, account takeover, and privileged workflow abuse, which makes it an identity governance issue.
• Teams should judge modern email security by behavioral detection, identity linkage, and operational simplification, not by how many perimeter tools they retain.

Key terms

• Secure Email Gateway: A secure email gateway is a control that filters incoming and outgoing email for malicious content, spoofing, and policy violations. It is strongest against known indicators, but it can miss socially engineered attacks, compromised senders, and abuse that only becomes visible after delivery.
• Behavioral Detection: Behavioral detection looks for suspicious patterns in how messages, users, and senders act over time rather than relying only on signatures or static rules. In identity-heavy attacks, it helps identify impersonation, compromised accounts, and abnormal interaction sequences that look legitimate at first glance.
• Account Takeover: Account takeover is unauthorized control of a user or service account after the attacker obtains valid credentials, session material, or equivalent access. In email-centric attacks, takeover often becomes the bridge from a single deceptive message to broader identity abuse and business process manipulation.

Deepen your knowledge

NHI governance, agentic AI identity, and machine identity lifecycle are core topics in our NHI Foundation Level course, the industry's only accredited NHI security programme. If you are responsible for identity security strategy or NHI governance in your organisation, it is worth exploring.

This post draws on content published by Abnormal AI: Innovate 2025 webinar on replacing secure email gateways with Microsoft plus Abnormal. Read the original.