CVE-2017-7494 in Samba
Summary
by MITRE
Samba since version 3.5.0 is vulnerable to remote code execution vulnerability, allowing a malicious client to upload a shared library to a writable share, and then cause the server to load and execute it.
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Analysis
by VulDB Data Team • 01/28/2025
The CVE-2017-7494 vulnerability represents a critical remote code execution flaw in the Samba file sharing service that has profound implications for network security infrastructure. This vulnerability affects Samba versions 3.5.0 and later, making it particularly concerning given the widespread deployment of Samba across enterprise environments and the critical role file sharing services play in organizational operations. The flaw stems from improper validation of share names during the SMB/CIFS protocol implementation, creating a pathway for malicious actors to execute arbitrary code on vulnerable systems.
The technical nature of this vulnerability lies in Samba's handling of writable shares and its dynamic library loading mechanism. When a malicious client connects to a writable share and uploads a shared library file with a specific naming convention, the server's processing logic fails to properly validate the file path, allowing the attacker to manipulate the library loading process. This creates a classic code injection scenario where the server loads and executes the attacker-controlled shared library with the privileges of the Samba service account. The vulnerability operates at the protocol level, making it particularly dangerous as it can be exploited without authentication in certain configurations, though it typically requires write access to a shared directory.
The operational impact of CVE-2017-7494 extends beyond simple remote code execution, as it can lead to complete system compromise and lateral movement within networks. Organizations running vulnerable Samba versions face significant risk of data breaches, system infiltration, and potential use as a foothold for broader attacks. The vulnerability's exploitation can result in persistent backdoors, data exfiltration, and the establishment of command and control channels. Security teams must consider this vulnerability as part of their threat modeling, particularly in environments where Samba serves as a critical file sharing service and where the service operates with elevated privileges.
Mitigation strategies for CVE-2017-7494 require immediate action including patching affected systems to Samba versions 4.6.4, 4.5.10, or 4.4.14, which contain the necessary fixes to prevent the vulnerable library loading behavior. Organizations should also implement network segmentation to limit access to Samba shares and disable unnecessary writable shares. The principle of least privilege should be enforced by configuring Samba shares with minimal required permissions and ensuring that the Samba service runs with reduced privileges. Additionally, monitoring for suspicious file uploads and unusual library loading patterns can help detect exploitation attempts. This vulnerability aligns with CWE-427 Uncontrolled Search Path Element and ATT&CK technique T1059 Command and Scripting Interpreter, highlighting the need for comprehensive defensive measures including network detection, endpoint protection, and regular security assessments to prevent successful exploitation.