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CVE-2021-36942

Microsoft Windows Local Security Authority (LSA) Spoofing

7.5 HIGHActively exploited (CISA KEV)Used in ransomwarePublic exploitEPSS 66.0%
  1. Published12 Aug 2021
  2. Added to CISA KEV3 Nov 2021
  3. Remediation due17 Nov 2021
Actively exploited (CISA KEV)

Microsoft Windows Local Security Authority (LSA) contains a spoofing vulnerability allowing an unauthenticated attacker to call a method on the LSARPC interface and coerce the domain controller to authenticate against another server using NTLM.

Added to KEV: 3 Nov 2021Federal remediation due: 17 Nov 2021Used in ransomware

Description

Windows LSA Spoofing Vulnerability

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityNone
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Affected products

Microsoft Windows Server 2004< 10.0.19041.1165
Microsoft Windows Server 2008r2
Microsoft Windows Server 2012r2
Microsoft Windows Server 2016< 10.0.14393.4583
Microsoft Windows Server 2019< 10.0.17763.2114
Microsoft Windows Server 20h2< 10.0.19042.1165

Remediation

Fixed in
Microsoft Windows Server 2004≥ 10.0.19041.1165
Microsoft Windows Server 2016≥ 10.0.14393.4583
Microsoft Windows Server 2019≥ 10.0.17763.2114
Microsoft Windows Server 20h2≥ 10.0.19042.1165

References

Frequently asked

Is CVE-2021-36942 being actively exploited?

Yes. CVE-2021-36942 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 3 Nov 2021. It has been used in ransomware campaigns.

How severe is CVE-2021-36942?

CVE-2021-36942 has a CVSS 3.1 base score of 7.5, rated high. EPSS estimates a 66.0% probability of exploitation.

Which products are affected by CVE-2021-36942?

Affected products include Microsoft Windows Server 2004, Microsoft Windows Server 2008, Microsoft Windows Server 2012, Microsoft Windows Server 2016, Microsoft Windows Server 2019, and 1 more.

How do I fix CVE-2021-36942?

Upgrade affected software to a fixed version, for example Microsoft Windows Server 2004 10.0.19041.1165, Microsoft Windows Server 2016 10.0.14393.4583, Microsoft Windows Server 2019 10.0.17763.2114 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2021-36942 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.