Security checks / Check reference / Conditional Access

Conditional Access Require Block Legacy Other Not Found

High Severity Microsoft 365 security check in the Conditional Access domain.

No Conditional Access policy blocks legacy "Other" client app type. Older protocols like MAPI, SMTP, POP, and IMAP remain open Legacy authentication protocols bypass MFA and Conditional Access entirely Attackers use these open paths for password spray and credential replay attacks Siemserva runs this check automatically across your tenant and maps every finding to the compliance frameworks below.

High SeverityConditional AccessSCuBA MS.AAD.1.1v1

Check summary

Severity

High

Domain

Conditional Access

Rank in domain

Frameworks

What this check verifies

No Conditional Access policy blocks legacy "Other" client app type. Older protocols like MAPI, SMTP, POP, and IMAP remain open

Why it matters

Legacy authentication protocols bypass MFA and Conditional Access entirely Attackers use these open paths for password spray and credential replay attacks

How to fix it

Create a CA policy blocking 'Other clients' for all users; test in report-only mode first

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 "Conditional Access Require Block Legacy Other Not Found" (source: https://senserva.com/check/imconditionalaccessrequireblocklegacyothernotfound.html):
- Verifies: No Conditional Access policy blocks legacy "Other" client app type. Older protocols like MAPI, SMTP, POP, and IMAP remain open
- Severity: High; domain: Conditional Access
- Risk: Legacy authentication protocols bypass MFA and Conditional Access entirely Attackers use these open paths for password spray and credential replay attacks
- Remediation guidance: Create a CA policy blocking 'Other clients' for all users; test in report-only mode first
- Compliance frameworks: SCuBA, MCSB, NIST, SOC2, CIS, HIPAA; SCuBA MS.AAD.1.1v1, MS.AAD.2.1v1, MS.AAD.2.2v1, MS.AAD.2.3v1, MS.AAD.3.1v1, MS.AAD.3.2v1; MCSB IM-6, IM-7
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:

SCuBAMCSBNISTSOC2CISHIPAASCuBA MS.AAD.1.1v1 SCuBA MS.AAD.2.1v1 SCuBA MS.AAD.2.2v1 SCuBA MS.AAD.2.3v1 SCuBA MS.AAD.3.1v1 SCuBA MS.AAD.3.2v1MCSB IM-6MCSB IM-7

References

learn.microsoft.com: /entra/identity/conditional-access/policy-block-le...learn.microsoft.com: /entra/identity/conditional-access/overview...learn.microsoft.com: /entra/identity/conditional-access/plan-conditiona...www.cisa.gov: /sites/default/files/2023-12/Azure%20Active%20Dire...

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Related Entra ID guides

This is an Entra ID and identity check. See the broader guidance and the exact checks Siemserva runs in this area:

Conditional Access analysis Entra ID security best practices Azure AD and Entra ID security All Conditional Access checks

Common questions

What does the Conditional Access Require Block Legacy Other Not Found check verify?

No Conditional Access policy blocks legacy "Other" client app type. Older protocols like MAPI, SMTP, POP, and IMAP remain open It is a High Severity check in the Conditional Access domain, one of the 650+ checks Siemserva runs across Microsoft 365, Intune, Defender, and Entra ID.

How do I fix a Conditional Access Require Block Legacy Other Not Found finding?

Create a CA policy blocking 'Other clients' for all users; test in report-only mode first 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, HIPAA, including SCuBA policy MS.AAD.1.1v1, MS.AAD.2.1v1, MS.AAD.2.2v1, MS.AAD.2.3v1, MS.AAD.3.1v1, MS.AAD.3.2v1, and MCSB controls IM-6, IM-7. 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.