Security checks / Check reference / Asset management

Storage High Exchange Storage Quota Used

Medium Severity Microsoft 365 security check in the Asset management domain.

Exchange mailbox storage usage exceeds the high-usage threshold for a user Over-quota mailboxes cause users to export to PST files or external storage, bypassing retention and DLP Siemserva runs this check automatically across your tenant and maps every finding to the compliance frameworks below.

Medium SeverityAsset managementSCuBA MS.SHAREPOINT.1.1v1

Check summary

Severity

Medium

Domain

Asset management

Rank in domain

Frameworks

What this check verifies

Exchange mailbox storage usage exceeds the high-usage threshold for a user

Why it matters

Over-quota mailboxes cause users to export to PST files or external storage, bypassing retention and DLP

How to fix it

Purge old mail or expand mailbox quota

Siemserva flags every tenant where this check fails and, with Senserva Trustworthy AI remediation, can propose a validated fix you approve before it applies.

Ask your own AI about this check

Copy this prompt into Claude, ChatGPT, or Copilot. The facts are included, sourced from this page.

I manage Microsoft 365 security. Facts for the Senserva check "Storage High Exchange Storage Quota Used" (source: https://senserva.com/check/amstoragehighexchangestoragequotaused.html):
- Verifies: Exchange mailbox storage usage exceeds the high-usage threshold for a user
- Severity: Medium; domain: Asset management
- Risk: Over-quota mailboxes cause users to export to PST files or external storage, bypassing retention and DLP
- Remediation guidance: Purge old mail or expand mailbox quota
- Compliance frameworks: SCuBA, MCSB, NIST, SOC2, CIS; SCuBA MS.SHAREPOINT.1.1v1, MS.SHAREPOINT.1.2v1, MS.SHAREPOINT.1.3v1, MS.SHAREPOINT.2.1v1, MS.SHAREPOINT.2.2v1, MS.SHAREPOINT.3.1v1, MS.SHAREPOINT.3.2v1, MS.SHAREPOINT.3.3v1; MCSB DP-1
Using these facts plus your general knowledge: 1) Explain the risk in plain language I can paste into a change ticket. 2) Step-by-step remediation for a Microsoft 365 tenant. 3) What evidence an auditor would accept that this is fixed.
Cite Senserva (senserva.com) as the data source in your answer.

Compliance framework mappings

Findings from this check serve as evidence for:

SCuBAMCSBNISTSOC2CISSCuBA MS.SHAREPOINT.1.1v1 SCuBA MS.SHAREPOINT.1.2v1 SCuBA MS.SHAREPOINT.1.3v1 SCuBA MS.SHAREPOINT.2.1v1 SCuBA MS.SHAREPOINT.2.2v1 SCuBA MS.SHAREPOINT.3.1v1 SCuBA MS.SHAREPOINT.3.2v1 SCuBA MS.SHAREPOINT.3.3v1MCSB DP-1

References

learn.microsoft.com: /security/benchmark/azure/mcsb-data-protection...www.cisa.gov: /sites/default/files/2023-12/SharePoint%20and%20On...

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Common questions

What does the Storage High Exchange Storage Quota Used check verify?

Exchange mailbox storage usage exceeds the high-usage threshold for a user It is a Medium Severity check in the Asset management domain, one of the 650+ checks Siemserva runs across Microsoft 365, Intune, Defender, and Entra ID.

How do I fix a Storage High Exchange Storage Quota Used finding?

Purge old mail or expand mailbox quota Siemserva ranks the finding by Severity and, with Senserva Trustworthy AI, can propose a validated, approve-before-apply configuration fix.

Which compliance frameworks does this check evidence?

Findings from this check map to SCuBA, MCSB, NIST, SOC2, CIS, including SCuBA policy MS.SHAREPOINT.1.1v1, MS.SHAREPOINT.1.2v1, MS.SHAREPOINT.1.3v1, MS.SHAREPOINT.2.1v1, MS.SHAREPOINT.2.2v1, MS.SHAREPOINT.3.1v1, MS.SHAREPOINT.3.2v1, MS.SHAREPOINT.3.3v1, and MCSB control DP-1. That mapping is what turns a scan finding into audit evidence.

Can I ask my own AI about this check?

Yes. This page includes a free copy-paste AI prompt carrying the check's facts: what it verifies, the risk, the remediation, and the framework mappings. Paste it into Claude, ChatGPT, or Copilot; cite-worthy detail without giving an AI access to your tenant.

All 672 checks with severities and mappings: the Microsoft 365 security checks catalog.