‍Email Is Full of Sensitive Data: How Cyera Secures Exchange Online

When a mailbox is compromised, security teams face an impossible question: What data was exposed? For years, answering that question has required manual exports, sampling, and guesswork. Exchange Online, one of the largest repositories of sensitive data in most enterprises, has remained a blind spot in data security programs.

Email is one of the highest-risk data surfaces in the enterprise. Customer records, financial documents, legal files, health data, and internal reports accumulate in mailboxes every day. Because email was never designed to enforce data governance, sensitive data spreads easily, persists for years, and often goes unnoticed.

To close this gap, Cyera supports coverage for Exchange Online by applying deep data discovery and classification across mailboxes, email bodies, and attachments. This gives security teams clear visibility into what sensitive data actually exists inside their email environment.

Visibility Where it Has Been Missing

Data security programs have traditionally focused on cloud storage, databases, and SaaS platforms. Email was treated as data in motion, monitored to prevent outbound exposure rather than governed as a datastore.

That model no longer reflects reality. Exchange Online holds years of attachments, conversations, and forwarded documents containing PII, PHI, and financial data. This data sits at rest, largely unclassified, and outside most governance workflows.

The gap becomes most obvious during incidents. Access can be cut off quickly, but without visibility into mailbox contents, teams are left exporting data and making assumptions under pressure.

With Cyera, user and shared mailboxes, email bodies, and attachments are scanned using the same discovery and classification approach applied across the rest of the data estate. Mailboxes are no longer opaque. They become visible, measurable, and governed.

From Visibility to Action

DLP policies focus on preventing outbound exposure, but they do not inventory or classify the sensitive data that accumulates at rest in mailboxes. Because email is a primary way teams exchange data, blocking messages is neither practical nor desirable. With Cyera providing visibility into Exchange Online, security teams can answer questions that previously required guesswork:

• Which mailboxes contain regulated or high-risk data
• Where sensitive attachments are stored, forwarded, or shared
• Whether email is being used for long-term storage of data that shouldn't live there

These questions surface constantly during audits, compliance reviews, incident response, and internal risk assessments. They are not theoretical. They come up when timelines are tight and stakes are high.

What changes with Exchange Online coverage is what happens next.

Instead of stopping at answers, teams can act. They can identify old sensitive emails, understand which mailboxes concentrate the most risk, and prioritize cleanup based on actual exposure rather than intuition. Retention enforcement becomes more consistent. Investigations move faster. Risk reduction becomes intentional rather than reactive.

During audits or internal reviews, teams no longer scramble to run searches or export inboxes. They can point to clear findings and documented risk with confidence.

Exchange Online often holds some of an organization's most sensitive data. Bringing clarity and control to email allows teams to manage that risk directly instead of working around it.

Getting Started with Exchange Online Coverage

Exchange Online coverage can be enabled directly within the Cyera platform using the existing Microsoft 365 integration. Once enabled, teams select which mailboxes to scan and begin discovering sensitive data across email bodies and attachments.

As scanning runs, findings appear in Cyera alongside other datastores, allowing security teams to identify high risk mailboxes and start prioritizing remediation without manual exports or ad hoc investigations.

Email Can't Remain Outside Data Security Governance

Email was never meant to be a system of record, yet for many organizations it has become one of the largest repositories of sensitive data. Leaving email outside of data security governance increases exposure and complicates incident response. Bringing Exchange Online into the DSPM model closes a critical gap. With visibility into what sensitive data lives in mailboxes, security teams can govern email alongside the rest of their data estate and reduce risk where it has quietly grown the longest.

Email is a datastore. It needs to be governed like one.

See Exchange Online Coverage in Action

To see how Cyera brings Exchange Online into data security governance and how sensitive email data appears alongside the rest of your data estate, request a demo.

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