Refreshing email security stacks: where Microsoft and SEGs overlap

At a glance

What this is: This on-demand webinar argues that Microsoft and secure email gateways duplicate features in ways that inflate cost and effort without materially improving coverage.

Why it matters: For IAM and security teams, the lesson is that identity-adjacent controls, email defenses, and operational workflows should be rationalised together rather than managed as separate tool silos.

👉 Watch Abnormal AI's webinar on refreshing email security stacks

Context

Email security stacks often become expensive because teams layer duplicate controls across Microsoft and secure email gateways, then keep both even when the overlap is operationally obvious. In practice, that creates a governance problem as much as a tooling problem: more products can mean more administration, more policy drift, and more time spent reconciling similar functions instead of reducing risk.

The identity connection is indirect but real. Email remains a common entry point for credential theft, session hijacking, and downstream account abuse, so the way organisations structure email security affects human identity protection, NHI token exposure, and the broader control environment around access.

Key questions

Q: How should teams decide which email security controls to keep when Microsoft and an SEG overlap?

A: Teams should keep the control that provides measurable coverage for the threats they actually face and remove duplicated enforcement where two tools do the same job. The decision should be based on detection quality, maintenance overhead, and incident outcomes, not on how many layers feel safer. A simple stack with clear ownership is usually easier to govern than a duplicated one.

Q: Why does redundant email security create more than just licensing waste?

A: Because duplicate controls create duplicate work. Every overlapping policy, exception, integration, and alert path adds operational burden and increases the chance of inconsistent decisions. That can slow triage, confuse ownership, and reduce the value of the stack even if no single tool is failing outright.

Q: How can security teams tell whether email stack consolidation is safe?

A: They should compare current and proposed stacks against real attack scenarios, then verify that advanced phishing, impersonation, and credential theft detection still works. If the removed layer does not materially improve detection or response, consolidation is usually safe. If it does, the organisation should preserve that capability even if other features overlap.

Q: What is the identity risk of treating email security as a separate problem from IAM?

A: Email is often the first path into identity compromise, so a weak mail stack can become a weak IAM outcome. Attackers use email to harvest passwords, steal sessions, or trigger malicious actions in linked workflows. Teams should therefore evaluate email controls as part of the broader identity protection model, not as an isolated channel.

Background and context

Where Microsoft and SEG overlap in email control coverage

Microsoft 365 security controls and secure email gateways often sit in the same control path, checking similar messages for phishing, malware, impersonation, and policy violations. When both are deployed without clear role separation, teams can end up paying twice for partially overlapping detection and response functions. The architectural issue is not that either class of tool is useless. It is that duplicated inspection, alerting, and remediation logic can create confusion about which system is authoritative for filtering, quarantine, and investigation.

Practical implication: map each control to a single owner and remove duplicated enforcement points before evaluating any upgrade.

Why redundant email security increases operational load

Redundancy in security stacks does not only affect licensing spend. Every duplicated rule set, exception list, integration, and analyst workflow adds maintenance overhead and increases the odds of inconsistent tuning. That matters in email security because false positives, delayed triage, and conflicting detections can be as disruptive as missed threats. If one platform can already enforce a given control reliably, keeping a second copy of the same function usually adds process friction more than resilience.

Practical implication: inventory duplicate workflows, then measure analyst time spent maintaining overlapping policies rather than just counting tools.

Advanced email threats still require differentiated detection

Removing redundant tools is not the same as accepting weaker protection. Email security still needs to catch socially engineered attacks, impersonation, and content that slips past static controls because it looks legitimate in context. The technical question is whether the remaining stack can detect behavior that a basic Microsoft plus SEG pairing misses, and whether the organisation can prove that with incident data rather than assumptions. Rationalisation only works when teams preserve coverage for the threats that actually bypass commodity filters.

Practical implication: keep only the controls that measurably improve detection of advanced email threats and retire the rest.

NHI Mgmt Group analysis

Email security sprawl is now a governance problem, not just a tooling problem. When Microsoft and a secure email gateway cover the same features, the organisation is paying for overlapping enforcement, overlapping tuning, and overlapping accountability. That duplication weakens clarity about which control is authoritative when incidents occur. Practitioners should treat stack rationalisation as part of control governance, not as a procurement cleanup exercise.

Duplicate email controls create cost, but duplicated workflows create real operational risk. Alert overlap, exception drift, and inconsistent quarantine policies force analysts to spend time reconciling systems instead of reducing exposure. This is especially costly when teams are already time-constrained, because the value of a control is diminished if maintaining it absorbs the capacity needed to respond. Practitioners should measure maintenance burden as part of control efficacy.

Reducing overlap is only defensible if advanced threat coverage remains intact. Email security still has to stop impersonation, socially engineered payloads, and abuse paths that commodity filtering misses. The right question is not whether to keep every product, but whether the remaining stack can prove it blocks the attacks that matter. Practitioners should validate coverage with incident evidence before removing any layer.

Identity teams should read email security consolidation through the lens of downstream access risk. Email is often the first step in human credential abuse and, by extension, in access to non-human identities protected through delegated inboxes, shared credentials, or token-triggered workflows. That makes stack design relevant to IAM, not just to mail security operations. Practitioners should align email defenses with the identity controls they are meant to protect.

From our research:

• Only 1.5 out of 10 organisations are highly confident in their ability to secure NHIs, compared to nearly 1 in 4 for securing human identities, according to The State of Non-Human Identity Security.
• Lack of credential rotation is cited as the top cause of NHI-related attacks by 45% of organisations, followed by inadequate monitoring and logging at 37% and over-privileged accounts at 37%, according to the same report.
• For the broader governance backdrop, see The 52 NHI breaches Report for breach patterns that show how control overlap, visibility gaps, and unmanaged access persist across identity programmes.

What this signals

Email security rationalisation is likely to accelerate as security teams look for control overlap they can remove without weakening protection. The deeper programme signal is that procurement, operations, and identity governance are converging, because the same access path that creates inbox risk can also create downstream identity compromise.

control overlap debt: when two products enforce the same security outcome, the real cost is not the second licence but the maintenance burden of keeping both tuned, reconciled, and defensible. Teams should treat that debt as a measurable governance problem, not an abstract architecture concern.

As organisations simplify email stacks, they should preserve controls that demonstrably reduce credential theft and impersonation risk while cutting duplicate inspection paths. That is the right balance for programmes that need both lower operational drag and stronger identity protection.

For practitioners

• Inventory overlapping email controls List the Microsoft and SEG features that perform the same filtering, quarantine, impersonation detection, and policy enforcement functions, then assign a single system of record for each control area.
• Measure analyst time spent on duplicated workflows Track how much time your team spends tuning duplicate rules, reconciling alerts, and resolving conflicting outcomes across platforms before deciding what to keep.
• Test retained coverage against advanced threats Validate the remaining stack against impersonation, payload delivery, and credential theft scenarios so consolidation does not remove the protections that actually reduce risk.
• Link email control decisions to identity risk Review whether inbox protections are reducing the chance of account takeover, delegated access abuse, or token exposure in downstream identity workflows.

Key takeaways

• Microsoft and secure email gateways often duplicate the same protective functions, which turns email security into a governance and cost problem as much as a technical one.
• The main risk of consolidation is not reduced simplicity, but removing a control that still adds measurable value against impersonation, phishing, or credential theft.
• Identity teams should evaluate email controls by their downstream effect on account compromise, not by the number of products in the stack.

Key terms

• Email security stack rationalisation: The process of reducing duplicated email protection capabilities across overlapping tools so that each control has a clear job and owner. In practice, rationalisation is as much about governance and operating model clarity as it is about cost cutting or vendor reduction.
• Control overlap: Control overlap occurs when two or more security products enforce the same outcome, such as filtering, quarantine, or impersonation detection. Overlap can add resilience, but it often creates extra tuning, inconsistent rules, and a larger operational burden if teams cannot prove distinct value.
• Downstream identity risk: Downstream identity risk is the chance that a security failure in one channel, such as email, becomes an access failure elsewhere, such as account takeover or token abuse. It is a useful lens for understanding how non-identity controls still shape IAM outcomes.

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: Doing More With Less in 2024: Refreshing Your Email Security. Read the original.