CVE-2009-2948 in Samba
Summary
by MITRE
mount.cifs in Samba 3.0 before 3.0.37, 3.2 before 3.2.15, 3.3 before 3.3.8 and 3.4 before 3.4.2, when mount.cifs is installed suid root, does not properly enforce permissions, which allows local users to read part of the credentials file and obtain the password by specifying the path to the credentials file and using the --verbose or -v option.
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Analysis
by VulDB Data Team • 02/03/2025
The vulnerability identified as CVE-2009-2948 represents a critical privilege escalation and credential disclosure issue within the Samba file sharing implementation, specifically affecting mount.cifs utility across multiple Samba versions. This flaw exists in the Samba software suite version 3.0.x prior to 3.0.37, 3.2.x prior to 3.2.15, 3.3.x prior to 3.3.8, and 3.4.x prior to 3.4.2, where the mount.cifs utility is installed with the setuid root bit set, creating a dangerous security boundary violation. The vulnerability stems from improper permission enforcement mechanisms within the mount.cifs utility, which is designed to mount CIFS/SMB shares from remote servers. When this utility operates with elevated privileges through the suid root setting, it should strictly enforce access controls to prevent unauthorized information disclosure. However, the implementation fails to properly validate or restrict file access permissions, allowing local users to exploit the verbose output functionality to extract partial credential information from the credentials file.
The technical exploitation of this vulnerability occurs through a specific attack vector involving the use of the --verbose or -v command line option in conjunction with explicit path specification to the credentials file. When the mount.cifs utility processes these options, it does not adequately sanitize or restrict the information it displays in verbose mode, inadvertently exposing portions of the credential data that contains the password. This vulnerability directly maps to CWE-200, which describes "Information Exposure" and specifically addresses situations where system information is disclosed to unauthorized users. The flaw demonstrates a classic case of insufficient output validation and privilege separation, where the elevated privileges granted through the suid bit are not properly enforced when processing user-provided input parameters. The attack requires local access to the system and knowledge of the credentials file path, but once executed, it provides attackers with partial password information that can be used for further exploitation.
The operational impact of this vulnerability extends beyond simple credential theft, as it enables attackers to potentially escalate privileges and gain unauthorized access to network resources. The exposure of partial credentials creates a significant risk for systems where Samba is used for enterprise file sharing, particularly in environments where users may have local shell access or where the mount.cifs utility is widely deployed. The vulnerability affects systems that rely on Samba for Windows file sharing compatibility and presents a substantial risk to organizations using these older Samba versions. Security practitioners should consider this issue in the context of the ATT&CK framework, specifically under the T1003 technique for Credential Dumping, where attackers attempt to extract passwords from memory or files. The vulnerability also relates to T1068 which covers privilege escalation techniques, as the ability to extract credentials can lead to further system compromise. Organizations should note that this vulnerability represents a failure in proper input validation and privilege separation, highlighting the importance of secure coding practices and the principle of least privilege in system design.
Mitigation strategies for CVE-2009-2948 involve immediate patching of affected Samba versions to the recommended secure releases, which include Samba 3.0.37, 3.2.15, 3.3.8, and 3.4.2 respectively. System administrators should also consider removing the suid bit from mount.cifs if the functionality is not critical, or implementing additional access controls to limit which users can invoke the utility with verbose options. The vulnerability demonstrates the critical importance of proper privilege management and input validation in security-sensitive utilities, particularly those designed to operate with elevated system privileges. Organizations should conduct comprehensive audits of their Samba installations to identify all affected systems and implement monitoring to detect potential exploitation attempts. The remediation process should include not only updating the software but also reviewing and hardening the configuration of file sharing services to prevent similar vulnerabilities in other components of the system infrastructure.