CVE-2012-2111 in Server
Summary
by MITRE
The (1) CreateAccount, (2) OpenAccount, (3) AddAccountRights, and (4) RemoveAccountRights LSA RPC procedures in smbd in Samba 3.4.x before 3.4.17, 3.5.x before 3.5.15, and 3.6.x before 3.6.5 do not properly restrict modifications to the privileges database, which allows remote authenticated users to obtain the "take ownership" privilege via an LSA connection.
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Analysis
by VulDB Data Team • 03/24/2021
The vulnerability identified as CVE-2012-2111 represents a critical privilege escalation flaw within the Samba implementation of Local Security Authority Remote Procedure Call (LSA RPC) procedures. This security weakness affects multiple Samba versions including 3.4.x prior to 3.4.17, 3.5.x prior to 3.5.15, and 3.6.x prior to 3.6.5, specifically impacting the CreateAccount, OpenAccount, AddAccountRights, and RemoveAccountRights functions. The flaw stems from inadequate validation of privilege modifications within the local security database, creating a pathway for authenticated attackers to manipulate security settings remotely. This vulnerability operates at the intersection of privilege management and remote code execution capabilities, as it allows attackers to escalate their privileges through manipulation of the underlying security database structure.
The technical implementation of this vulnerability lies in the insufficient input validation and privilege checking mechanisms within the LSA RPC interfaces. When authenticated users connect to the Samba server via LSA RPC connections, they can exploit the lack of proper access controls to modify account rights without appropriate authorization. The vulnerability specifically targets the privilege database modification process, where the system fails to verify whether the requesting user has sufficient privileges to perform operations such as granting "take ownership" rights. This flaw is categorized under CWE-264, which addresses permissions, privileges, and access control issues, and aligns with ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" through the manipulation of system-level access controls. The vulnerability's exploitation requires only authenticated access, making it particularly dangerous as it can be leveraged by users who already have legitimate access to the system but lack administrative privileges.
The operational impact of CVE-2012-2111 extends beyond simple privilege escalation to encompass potential full system compromise. An attacker who successfully exploits this vulnerability can obtain the "take ownership" privilege, which grants them the ability to modify or delete any file or directory on the system regardless of the original access controls. This capability enables attackers to bypass standard file system protections and potentially gain access to sensitive system information, modify critical system files, or establish persistent access through privilege escalation. The vulnerability's remote nature means that attackers can exploit it from external networks without requiring physical access to the system. The implications include unauthorized data access, system integrity compromise, and potential lateral movement within network environments where Samba servers serve as file sharing or authentication points. Organizations using affected Samba versions face increased risk of data breaches and system compromise, particularly in environments where Samba servers handle sensitive data or serve as domain controllers.
Mitigation strategies for CVE-2012-2111 primarily involve immediate patching of affected Samba installations to versions that address the privilege validation flaws. System administrators should prioritize updating all affected Samba servers to versions 3.4.17, 3.5.15, or 3.6.5 respectively, depending on their current version. Additionally, network segmentation and access control measures should be implemented to limit access to Samba services, particularly restricting LSA RPC connections to trusted network segments only. Monitoring for unauthorized access attempts to LSA RPC interfaces should be enabled, and security audits should verify that privilege assignments are properly configured and that only authorized users have access to administrative functions. The vulnerability highlights the importance of implementing principle of least privilege controls and regular security assessments of critical system components. Organizations should also consider implementing additional layers of security such as network access control lists, intrusion detection systems, and regular vulnerability scanning to detect and prevent exploitation attempts. The fix implemented in the patched versions addresses the root cause by strengthening the privilege validation mechanisms within the LSA RPC procedures, ensuring that only users with appropriate administrative credentials can modify account rights and security settings.