CVE-2014-8143 in Samba
Summary
by MITRE
Samba 4.0.x before 4.0.24, 4.1.x before 4.1.16, and 4.2.x before 4.2rc4, when an Active Directory Domain Controller (AD DC) is configured, allows remote authenticated users to set the LDB userAccountControl UF_SERVER_TRUST_ACCOUNT bit, and consequently gain privileges, by leveraging delegation of authority for user-account or computer-account creation.
If you want to get best quality of vulnerability data, you may have to visit VulDB.
Analysis
by VulDB Data Team • 03/05/2022
The vulnerability identified as CVE-2014-8143 represents a significant privilege escalation flaw within Samba's Active Directory Domain Controller implementation. This issue affects multiple versions of the Samba software including 4.0.x versions prior to 4.0.24, 4.1.x versions prior to 4.1.16, and 4.2.x versions prior to 4.2rc4. The flaw specifically targets environments where Samba operates as an Active Directory Domain Controller, making it particularly dangerous in enterprise network infrastructures where Active Directory services are critical for authentication and authorization.
The technical exploitation of this vulnerability stems from improper validation of userAccountControl flags during account creation processes. When legitimate users with appropriate permissions attempt to create user or computer accounts within the domain, the system fails to properly validate whether these users possess the authority to set the LDB userAccountControl UF_SERVER_TRUST_ACCOUNT bit. This bit, when properly set, grants accounts elevated privileges equivalent to server trust accounts, effectively allowing attackers to bypass normal access controls and gain unauthorized administrative capabilities within the domain environment.
The operational impact of CVE-2014-8143 extends beyond simple privilege escalation as it enables attackers to assume the identity of server trust accounts, which typically have extensive permissions within Active Directory environments. This vulnerability aligns with CWE-264, which categorizes "Permissions, Privileges, and Access Controls" as a critical concern in software security. The flaw essentially allows attackers to leverage legitimate delegation mechanisms to perform unauthorized actions that should only be available to domain administrators or privileged service accounts.
From an adversarial perspective, this vulnerability demonstrates the dangers of improper access control implementation in distributed authentication systems. Attackers can exploit the delegation of authority mechanism that is normally designed to enable legitimate administrative tasks to instead gain unauthorized access to privileged accounts. This represents a classic case of privilege escalation through improper authorization checks, where the system fails to validate that the requesting user has the appropriate permissions to set specific account control flags. The attack vector requires only remote authenticated access, meaning that an attacker with valid domain credentials can exploit this vulnerability without requiring physical access or additional authentication mechanisms.
The security implications of this vulnerability are particularly severe in enterprise environments where Samba serves as a critical component of Active Directory infrastructure. Organizations that have not updated their Samba installations to versions that address this vulnerability face significant risk of unauthorized privilege escalation attacks that could compromise entire domain environments. The mitigation strategy involves updating to patched versions of Samba, specifically versions 4.0.24, 4.1.16, and 4.2rc4 or later. Additionally, organizations should implement proper network segmentation and access controls to limit the impact of potential exploitation attempts, while monitoring for unauthorized account creation activities that might indicate attempted exploitation of this vulnerability. This vulnerability also highlights the importance of proper input validation and access control enforcement in distributed systems, aligning with ATT&CK technique T1078 for Valid Accounts and T1484 for Domain Policy Modification, which both relate to unauthorized access and privilege escalation within network environments.