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Incorrect Privilege AssignmentWeakness · CWE-266

CVE-2020-25720

HIGH · 7.5 CVSS v3.1 Published 2024-11-17
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
81/100
Remediation priority · High
Remotely reachable Zero-click

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
A vulnerability was found in Samba where a delegated administrator with permission to create objects in Active Directory can write to all attributes of the newly created object, including security-sensitive attributes, even after the object's creation. This issue occurs because the administrator owns the object due to the lack of an Access Control List (ACL) at the time of creation and later being recognized as the 'creator owner.' The retained significant rights of the delegated administrator may not be well understood, potentially leading to unintended privilege escalation or security risks.

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 · high confidence

A vulnerability in Samba's Active Directory implementation allows delegated administrators who create objects to retain full write access to all attributes of those objects due to missing ACL application at creation time, making them the 'creator owner' with excessive privileges and enabling potential privilege escalation.

MitigationImplement proper default security descriptors and ACL inheritance for newly created objects in Samba AD to prevent delegated administrators from retaining excessive write access to security-sensitive attributes.

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

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
Network
Complexity
High
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

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 Samba installation and version
    Run 'samba --version' or check the package manager for the installed Samba version
    Affected if Samba version is 4.0.0 through 4.13.17, 4.14.0 through 4.14.12, or 4.15.0 through 4.15.5 (or any version before 4.13.17, 4.14.12, or 4.15.5)
  2. Confirm Samba is running as an Active Directory Domain Controller
    Check smb.conf for 'server role = active directory domain controller' or run 'samba-tool domain level show'
    Affected if Samba is configured as an AD DC and the version is within the affected range
  3. Identify delegated administrators in the AD domain
    Run 'samba-tool user list' and cross-reference with administrative group memberships using 'wbinfo --group-info <groupname>' or LDAP queries against the AD schema
    Affected if Delegated administrator accounts exist who were granted Create Child permissions
  4. Examine ACLs on objects created by delegated administrators
    Use 'ldbsearch' or Windows RSAT tools to query the ntSecurityDescriptor attribute on specific AD objects, comparing the owner and DACL against expected default security descriptors
    Affected if The creator owner has write access to security-sensitive attributes (such as userPassword, member, or ntPwdHistory) beyond what the default schema should allow
  5. Check for ACL inheritance issues on organizational units
    Query the 'ntSecurityDescriptor' attribute on OUs where delegated admins created objects, looking for cases where the 'owner' attribute differs from the expected domain admin or the DACL grants explicit write permissions to the creator
    Affected if ACL inheritance is disabled or the security descriptor was not properly applied at object creation time, leaving the creator with retained write access

A system is affected if Samba AD DC is running a version before 4.13.17, 4.14.12, or 4.15.5 and delegated administrators who created AD objects retain excessive write access to those objects' security-sensitive attributes.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement proper default security descriptors and ACL inheritance for newly created objects in Samba AD to prevent delegated administrators from retaining excessive write access to security-sensitive attributes.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing3.0 h
  • Review / QA2.0 h
11.0 hours of engineering $1,930
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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-2020-25720 in production — separate from our analysis above.

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