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Actively exploited in the wild. This CVE is on the CISA Known Exploited Vulnerabilities list — treat remediation as urgent. Federal remediation due by 3 May 2022. Known ransomware use
FedoraOperating system · Fedoraproject

CVE-2020-1472

MEDIUM · 5.5 CVSS v3.1 Published 2020-08-17
Patch available
A vendor patch is available. No clean upgrade release — apply the published patch.
See remediation →
96/100
Remediation priority · Urgent
In the wild Ransomware High EPSS Public exploit Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
An elevation of privilege vulnerability exists when an attacker establishes a vulnerable Netlogon secure channel connection to a domain controller, using the Netlogon Remote Protocol (MS-NRPC). An attacker who successfully exploited the vulnerability could run a specially crafted application on a device on the network. To exploit the vulnerability, an unauthenticated attacker would be required to use MS-NRPC to connect to a domain controller to obtain domain administrator access. Microsoft is addressing the vulnerability in a phased two-part rollout. These updates address the vulnerability by modifying how Netlogon handles the usage of Netlogon secure channels. For guidelines on how to manage the changes required for this vulnerability and more information on the phased rollout, see How to manage the changes in Netlogon secure channel connections associated with CVE-2020-1472 (updated September 28, 2020). When the second phase of Windows updates become available in Q1 2021, customers will be notified via a revision to this security vulnerability. If you wish to be notified when these updates are released, we recommend that you register for the security notifications mailer to be alerted of content changes to this advisory. See Microsoft Technical Security Notifications.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

CVE-2020-1472 is an elevation of privilege vulnerability in the Netlogon Remote Protocol (MS-NRPC) that allows unauthenticated attackers to establish vulnerable Netlogon secure channel connections to domain controllers and potentially gain domain administrator access. Microsoft is addressing this through a phased two-part rollout that modifies how Netlogon handles secure channel connections.

MitigationApply Microsoft's phased Windows updates for CVE-2020-1472, which modify Netlogon secure channel handling. Organizations should review Microsoft's guidance on managing Netlogon secure channel connection changes and prepare for the second-phase enforcement updates planned for Q1 2021.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
FedoraOperating system
Affected:= 31= 32= 33
Ubuntu LinuxOperating system
Affected:= 14.04= 16.04= 18.04= 20.04
Debian LinuxOperating system
Affected:= 9.0
Windows Server 1903Operating system
Affected:all versions
Windows Server 1909Operating system
Affected:all versions
Windows Server 2004Operating system
Affected:all versions
Windows Server 2008Operating system
Affected:= r2
Windows Server 2012Operating system
Affected:all versions= r2

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if the system is a domain controller or AD member
    For Windows: check System Information or run 'netdom query /domain:YOUR_DOMAIN dc' to list domain controllers. For Linux: check if Samba is configured as an Active Directory domain controller (smb.conf with 'server role = active directory domain controller').
    Affected if The system is a Windows domain controller or a Linux system running Samba as an AD domain controller.
  2. Verify if the Netlogon service (MS-NRPC) is listening or accessible
    For Windows: run 'nltest /dbflag:0x20810000' to check Netlogon debug flags or use PowerShell to query the Netlogon service status. For Linux: check if Samba's Netlogon server is enabled (look for 'netlogon' share in smb.conf).
    Affected if The Netlogon service is running and accepting connections on the system.
  3. Confirm the Windows Server version matches the affected range
    Run 'winver' or check System Properties to identify the exact Windows Server version (1903, 1909, 2004, 2008 R2, 2012, 2012 R2). Compare against the listed affected versions in the CVE description.
    Affected if The Windows Server version is 1903, 1909, 2004, 2008 R2, 2012, or 2012 R2 and the system is a domain controller.
  4. Check if the security update for CVE-2020-1472 is installed
    On Windows: open 'View installed updates' in Control Panel or run 'wmic qfe list' to list installed hotfixes. Look for KB4557222 or later related security updates for Netlogon.
    Affected if The specific CVE-2020-1472 security update is NOT installed on the domain controller.
  5. For Linux, verify Samba version if acting as AD DC
    On Fedora/Ubuntu/Debian: run 'smbd --version' or check the installed Samba package version (rpm -q samba or dpkg -l samba). Compare against versions that include the CVE fix.
    Affected if The Linux system runs Samba as an AD domain controller and the Samba version predates the CVE fix.

A system is affected if it is a domain controller (Windows or Samba-based Linux) running a vulnerable version of Netlogon/MS-NRPC without the CVE-2020-1472 security update installed.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Patch available Apply the vendor patch
Vendor patch portal.msrc.microsoft.com →
Interim mitigation

Apply Microsoft's phased Windows updates for CVE-2020-1472, which modify Netlogon secure channel handling. Organizations should review Microsoft's guidance on managing Netlogon secure channel connection changes and prepare for the second-phase enforcement updates planned for Q1 2021.

Recommended fix High confidence

Microsoft security updates KB4571694/KB4571703/KB4571744 (or later) for Windows Server; Samba packages with CVE-2020-1472 fixes for Linux distributions

  1. For Windows servers: Apply the Microsoft security update for CVE-2020-1472 (August 2020 Update or later) corresponding to your Windows Server version (KB4571694, KB4571703, KB4571744, or similar depending on OS)
  2. For Linux systems (Fedora, Ubuntu, Debian) running Samba: Run distribution-specific package update commands (e.g., 'dnf update' for Fedora, 'apt-get update && apt-get upgrade' for Ubuntu/Debian) to obtain Samba security patches
  3. Verify the Netlogon secure channel enforcement is enabled by checking that the registry key 'RequireStrictKeyDistribution' is set to 1 on domain controllers, or apply Group Policy settings to enforce machine account password changes
  4. After applying updates, restart affected servers to ensure patches take effect
  5. For Phase 2 (enforcement mode, Q1 2021): Ensure all non-compliant devices are identified and remediated before the enforcement phase begins - Microsoft provides scripts to audit compliance
Caveat Ensure applications relying on vulnerable Netlogon implementations are updated; non-compliant devices may lose domain connectivity after Phase 2 enforcement begins in 2021

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Fedora Exploited in the wild — priority engagement
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
22.0 hours of engineering $3,860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-1472 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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