Microsoft Leads Transparency in Email Security Benchmarking and Threat Defense

Microsoft’s recent move toward greater transparency in email security effectiveness offers a timely and much-needed step forward for organizations seeking to stay a step ahead of relentless and evolving cyber threats. Over the past decade, the threat landscape has shifted dramatically: cyberattackers now leverage automation, artificial intelligence, and sophisticated social engineering tactics to breach even the most fortified environments. As email remains a primary vector for phishing, malware, and credential theft, a clear and accurate understanding of how protective tools like Microsoft Defender for Office 365 perform is no longer optional—it's essential.

The Challenge: Transparency and Benchmarking in Email Security​

For years, email security has struggled with a lack of standardized benchmarks and consistent reporting. CISOs and security architects often find themselves evaluating products on the basis of marketing claims, isolated anecdotal results, or synthetic test environments that fail to reflect the messy realities of day-to-day threats. This opacity hampers objective decision-making and may even lull organizations into a false sense of security.
Microsoft’s acknowledgment of this industry-wide gap represents an important inflection point. With both the platform responsibilities of Microsoft 365 and its role as a security solution provider, Microsoft has unique visibility into both the scale and nuance of real-world email threats. Yet, as the company admits, transparency is vital for building and maintaining trust among customers—especially when organizations are layering security technologies and want confidence in the actual, rather than theoretical, protection delivered.

Two Key Initiatives for Improved Email Security Insights​

Microsoft’s twin initiatives—an advanced customer-facing dashboard and the publication of comparative benchmarking studies—aim to address these transparency and data clarity concerns head-on.

A Customer-Facing Dashboard: Tracking Every Threat Vector​

The new overview dashboard within Microsoft Defender for Office 365 is designed to give security teams comprehensive visibility into:

• Pre-delivery threats blocked: Malware, phishing, and policy violations halted before landing in user inboxes.
• Post-delivery threats mitigated: Remediation actions such as automatic removal of malicious emails that slipped through on initial delivery (for example, as threat intelligence updates or zero-hour auto purges trigger after-the-fact cleans).
• “Missed” threat tracking: Critical for understanding residual risk, these are threats that reached end users and were not remediated in time or by automation.

Significantly, features like Safe Links and Safe Attachments have their protection impact measured and reported, helping organizations determine exactly how and where their risk surface is being reduced. By surfacing precisely how many threats are blocked (and at what stage), Microsoft is aiming to answer security leaders’ most pressing question: “How are my users being protected—across email and platforms like Teams?”

Comparative Benchmarking Reports: Real-World, Not Synthetic Tests​

Recognizing that customers often deploy layered security—mixing native Microsoft protection with Secure Email Gateways (SEGs) or Integrated Cloud Email Security (ICES) vendors—Microsoft has prioritized benchmarking that mirrors real-world deployments.
Rather than relying on test labs with contrived attacks, Microsoft’s reports are derived from live threat telemetry: real emails, real attacks, and real customer configurations across millions of mailboxes. The company’s analysis compares three primary scenarios:

• Microsoft Defender for Office 365 alone
• Defender plus SEG (with the SEG positioned in front)
• Defender plus ICES (with ICES operating after delivery to the mailbox)

Both datasets are aggregated, anonymized, and scrubbed according to Microsoft’s privacy principles, akin to what’s found in their annual Digital Defense Report.

Examining the Benchmarking Methodology​

SECURE EMAIL GATEWAYS (SEGs)​

SEGs have long been the workhorses of email filtering, offering pre-delivery scanning for spam, malware, and policy violations. While the email security market is slowly migrating to cloud-native solutions, many organizations—particularly those in regulated industries—still deploy SEGs as their first line of defense.
Microsoft’s Approach:
Microsoft evaluated seven leading SEG vendors, capturing and normalizing missed-threat data per 1,000 protected users. Importantly, Microsoft applied stricter standards to its own stack: for Defender, even threats remediated post-delivery (i.e., caught and removed after reaching a user) were categorized as “missed,” whereas SEG-missed threats included anything not stopped pre-delivery or not remediated shortly afterwards.

Findings​

• Defender for Office 365 missed fewer threats than any of the SEGs benchmarked.
• Methodological rigor is enhanced by clear definitions and uniform data normalization, but the stricter classification standard applied to Defender for Office may mean reported results are slightly more conservative for Microsoft's own effectiveness.

INTEGRATED CLOUD EMAIL SECURITY (ICES) VENDORS​

ICES products have emerged to deliver supplemental, cloud-native detection and investigation that operates after mail arrives at the mailbox, focusing on nuanced attack patterns, business email compromise, and targeted phishing.
How Microsoft Measured ICES Value:

• Catch attribution: When ICES moves a message (Inbox, Junk, or other folders) based on detecting a threat, it counts as an ICES catch— unless Defender for Office 365 already classified that message as malicious or spam (in which case it’s considered a duplicate catch).
• Categories analyzed:
• Marketing & bulk (promotional, non-malicious mail)
• Spam (unsolicited or nuisance, but not malicious)
• Malicious (phishing, malware, etc.)
• Non-malicious (possible false positives or user-driven moves)
• Results are normalized by Defender’s own catch rates, making it easier to quantify “value added.”

Key Results​

• Marketing and bulk detection saw the greatest improvement from ICES layering, with an average enhancement of 20% in detection and filtering, helping to declutter users’ inboxes.
• For malicious and spam messages, improvement was minor—averaging 0.3% (malicious) and 0.51% (spam). This suggests that, at scale, Microsoft Defender for Office 365 already flags and neutralizes the vast majority of outright threats, with ICES value becoming more incremental at the high end.

Industry Review and Methodological Validation​

Microsoft’s benchmarking and transparency claims were submitted to SE Labs—regarded as a neutral authority in email security testing—for external validation. SE Labs CEO Simon Edwards publicly supported Microsoft’s use of live threat data, highlighting its superiority over artificial testing for understanding real-world product efficacy.
Nonetheless, the value of synthetic, targeted tests was not dismissed. Synthetic testing allows security experts to probe responses to novel or highly specific attack techniques that may not appear with regular frequency in everyday customer workloads. The clearest industry consensus, then, is that both types of testing together offer the most nuanced and actionable insight.

Critical Analysis: Where Microsoft’s Transparency Push Succeeds​

Strengths​

1. Alignment With Real-World Threats​

By prioritizing actual, anonymized email flow analysis over test-lab scenarios, Microsoft is setting a new precedent for the email security sector. For organizations, this means less guesswork and more decisions driven by practical risk data. Few other providers can leverage such massive, diverse datasets across as many environments.

2. Granularity and Actionability​

The new dashboard’s breakdown—showing threats blocked, threats remediated, and missed threats by vector and defense component—enables security teams to perform more meaningful postmortems. Organizations can quickly gauge not only if a threat bypassed defenses, but how and at what layer, informing better defensive reconfiguration and staffing.

3. Vendor-Neutral Benchmarking​

Defender for Office 365 isn’t compared only with third parties; Microsoft’s reports candidly illustrate where competitive ICES and SEG vendors provide incremental value and where overlap may exist. By applying stricter standards for measuring their own platform’s misses, Microsoft avoids the “fox guarding the henhouse” perception that can dog vendor-run benchmarks.

4. Independent Methodology Review​

Enlisting SE Labs to audit processes helps address inevitable skepticism about vendor-funded research. It indicates a willingness to engage with the broader community and apply best-practice scientific standards, not just commercial interests.

5. Commitment to Ongoing Updates​

Rather than a one-off publication, Microsoft commits to quarterly updates—a vital improvement given how quickly attacker tactics and techniques evolve. Quarterly updates allow organizations to track both improvement and regression over time.

Potential Caveats and Risks​

1. Benchmark Blindspots​

While Microsoft’s scale of telemetry is impressive, it reflects primarily the behavior of organizations already using their products—potentially creating a sampling bias that may not fully represent conditions that exist in enterprises running alternative platforms, setups, or threat profiles.

2. “Missed” Threat Definition Strictures​

By holding itself to a stricter “missed” threat definition (post-delivery remediation counted as a miss), Microsoft likely under-reports its own effectiveness relative to SEG and ICES competitors. While this is intellectually honest and increases trust, customers should be mindful of this nuance when interpreting comparative data.

3. Incremental ICES Value for Critical Threats​

While ICES delivers clear sound value for decluttering marketing and low-stakes “nuisance” mail, its incremental benefit for stopping true malicious threats atop Defender for Office 365 appears marginal (0.3%). For resource-constrained organizations, the cost-benefit for licensing, deploying, and managing additional ICES layers may be modest—unless niche threat detection or compliance goals demand it.

4. Lack of Complete Cross-Vendor Transparency​

Although Microsoft’s methodology and vendor inclusion seem fair, not all vendor-specific data or comparative granular breakdowns may be publishable by Microsoft alone—especially for third-party SEG and ICES solutions. Full transparency often demands industry-wide cooperation, open testing initiatives, and possibly further third-party oversight.

5. Real-World Data != Comprehensive Foresight​

Even with broad visibility, relying solely on observed attacks can miss “black swan” events—advanced persistent threats (APTs), new zero-day exploits, or attack patterns designed specifically to evade known telemetry. Organizations should still simulate sophisticated or rare attack scenarios as needed, using a mix of vendor and independent test frameworks.

Implications for Security Teams and CISOs​

The threat landscape is only accelerating in complexity. Hybrid work, cloud adoption, and the fast-moving tactics of sophisticated threat actors mean that old playbooks—blind reliance on perimeter SEG, or unexamined trust in a single vendor’s detection rate—are no longer fit for purpose.
Microsoft’s new transparency initiatives empower security leaders to:

• Calibrate investment in layered controls: Quantify exactly what is gained (and what may be redundant) by operating SEGs or ICES solutions in tandem with Microsoft Defender for Office 365.
• Fine-tune user experience and productivity: By understanding how marketing clutter and spam are handled, organizations can design policies that strike the right balance between safety and seamless communication.
• Drive accountability and improvement: With regular benchmarking updates, security teams can rapidly detect when efficacy drops and push vendors for roadmap enhancements.
• Insist on open validation: Independent, repeatable tests—externally reviewed—should become table stakes for all vendors, not just Microsoft.

The Broader Email Security Landscape: A Call for Industry-Wide Transparency​

Microsoft’s initiative sets a new bar—but true, lasting transparency in email security demands an ecosystem approach. No vendor, however large, operates in a vacuum. Security teams may mix and match cloud-native and on-prem solutions, deploy advanced threat intelligence feeds, or change configuration templates to meet internal compliance requirements. For a true “trust but verify” approach, the industry needs:

• Common benchmarking standards: Agreements on data normalization, miss definitions, and reporting frameworks across vendors.
• Open and collaborative testing environments: Like the MITRE ATT&CK Evaluations for endpoint security, a neutral arena for comparative email security testing where all vendors submit to the same simulated threat streams and real-world volumes.
• Transparent, privacy-preserving data sharing: Aggregated metrics that securely compare results across vendors, without revealing sensitive customer-specific information.

Future Directions: What to Watch Next​

Microsoft’s commitment to quarterly benchmark updates, combined with open engagement with reviewers and customers, suggests we are entering a new era of continuous improvement and radical candor in security performance measurement.
Key developments to monitor include:

• Evolution of dashboard capabilities: Will future iterations allow customers to drill down to threat-specific insights—such as details on novel zero-day attacks, internal phishing simulation outcomes, or business email compromise detection?
• Adoption of transparency standards by competitors: Will other cloud providers, SEGs, and ICES vendors follow suit by publishing their own real-world effectiveness data with equivalent rigor and independent review?
• Emergence of cross-platform analytics: As organizations continue deploying multi-vendor stacks, demand will grow for analytics tools that normalize threat data across products, not just within one vendor’s ecosystem.
• Impact on procurement and compliance frameworks: Will regulators or compliance bodies begin requiring demonstrated, independently certified email security performance metrics in high-risk sectors?

Conclusion: Turning the Tide in Email Security Effectiveness​

Microsoft’s recent push to illuminate the black box of email security effectiveness is more than a marketing move—it’s an industry wake-up call. By offering granular, independently-reviewed, and regularly-updated data, Microsoft is both challenging competitors and arming customers with the data-driven tools they need to make more informed decisions. In an era of “assume breach” and escalating risk, CISOs can no longer afford opacity.
While caveats remain—especially regarding benchmarking scope and the need for broader industry alignment—Microsoft’s initiatives undeniably push the conversation forward. The open question now is whether the rest of the ecosystem will join in, creating a future where security is not only a team sport among defenders but one where radical transparency is the new cybersecurity baseline.
For organizations relying on email as the lifeblood of communication—and for the professionals protecting it—the era of flying blind may, finally, be ending.

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Source: Microsoft Transparency on Microsoft Defender for Office 365 email security effectiveness | Microsoft Security Blog