CVE-2018-8340 — A security feature bypass vulnerability exists when Active Directory Federation

A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka "AD FS Security Feature Bypass Vulnerability." This affects Windows Server 2016, Windows Server 2012 R2, Windows

01What is this vulnerability?

A security feature bypass vulnerability exists when Active Directory Federation Services (AD FS) improperly handles multi-factor authentication requests, aka "AD FS Security Feature Bypass Vulnerability." This affects Windows Server 2016, Windows Server 2012 R2, Windows 10 Servers.

02Affected products

Vendor	Product	Versions
Microsoft	Windows Server 2016	(Server Core installation)
Microsoft	Windows Server 2012 R2	(Server Core installation)
Microsoft	Windows 10 Servers	version 1709 (Server Core Installation), version 1803 (Server Core Installation)

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2018-08-15T17:00:00.000Z
• Last modified: 2024-08-05T06:54:35.395Z

09References

• www.securitytracker.com — http://www.securitytracker.com/id/1041474
• www.securityfocus.com — http://www.securityfocus.com/bid/105029
• portal.msrc.microsoft.com — https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2018-8340