Security checks / Check reference / Tenant-wide
Fasthttp Used
Medium Severity Microsoft 365 security check in the Tenant-wide domain.
FastHTTP client library detected in sign-in user agent. Commonly used by automated attack tools for credential stuffing and brute-force attacks Alternate HTTP stacks without hardened settings reduce transport protections and increase misconfiguration risk Siemserva runs this check automatically across your tenant and maps every finding to the compliance frameworks below.
Check summary
What this check verifies
FastHTTP client library detected in sign-in user agent. Commonly used by automated attack tools for credential stuffing and brute-force attacks
Why it matters
Alternate HTTP stacks without hardened settings reduce transport protections and increase misconfiguration risk
How to fix it
Validate TLS settings, headers, and dependency versions on the HTTP stack
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.
Compliance framework mappings
Findings from this check serve as evidence for:
Related Tenant-wide checks
Common questions
What does the Fasthttp Used check verify?
FastHTTP client library detected in sign-in user agent. Commonly used by automated attack tools for credential stuffing and brute-force attacks It is a Medium Severity check in the Tenant-wide domain, one of the 650+ checks Siemserva runs across Microsoft 365, Intune, Defender, and Entra ID.
How do I fix a Fasthttp Used finding?
Validate TLS settings, headers, and dependency versions on the HTTP stack 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, and MCSB control LT-3. 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.