CVE-2007-4687 in Mac OS X
Summary
by MITRE
The remote_cmds component in Apple Mac OS X 10.4 through 10.4.10 contains a symbolic link from the tftpboot private directory to the root directory, which allows tftpd users to escape the private directory and access arbitrary files.
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Analysis
by VulDB Data Team • 06/07/2025
The vulnerability described in CVE-2007-4687 represents a critical directory traversal flaw within the remote_cmds component of Apple Mac OS X versions 10.4 through 10.4.10. This issue specifically affects the Trivial File Transfer Protocol daemon (tftpd) which operates within the tftpboot private directory structure. The fundamental problem arises from improper directory handling that creates a symbolic link pointing from the restricted tftpboot directory to the root directory, thereby undermining the intended security boundaries of the private filesystem space.
This technical flaw stems from inadequate path validation and directory isolation mechanisms within the tftpd implementation. When tftpd processes file transfer requests, it fails to properly constrain file access to the designated tftpboot directory, allowing authenticated users with tftpd privileges to traverse beyond the intended boundaries. The symbolic link creates an unintended path that bypasses normal access controls, enabling attackers to access arbitrary files on the system that should otherwise remain protected within the tftpboot private directory structure. This vulnerability directly maps to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as directory traversal or path traversal attacks.
The operational impact of this vulnerability is significant, as it provides unauthorized file access capabilities to users who can authenticate to the tftpd service. Attackers can leverage this flaw to read sensitive system files, configuration data, and potentially access other system resources that should be isolated within the tftpboot directory. The vulnerability affects the core security model of the operating system's network services, potentially exposing system integrity and confidentiality. From an attacker's perspective, this represents a privilege escalation opportunity that could lead to further system compromise, making it particularly dangerous in multi-user environments where tftpd services are enabled.
The security implications extend beyond simple file access, as this vulnerability can be exploited to gain information about the system's file structure and potentially identify other security weaknesses. Network-based attackers who can establish connections to the tftpd service can exploit this flaw without requiring local system access, making it particularly dangerous in networked environments. The vulnerability aligns with ATT&CK technique T1083, which covers directory and file system discovery, as it provides attackers with elevated access to system file structures that would normally be restricted. Organizations running affected Mac OS X versions face significant risk of data exposure and potential system compromise, particularly in environments where tftpd services are actively used for network file transfers.
Mitigation strategies should focus on immediate patch application for the affected Mac OS X versions, along with proper configuration of tftpd services to ensure they operate within properly restricted directories. System administrators should disable unnecessary tftpd services and implement proper access controls to limit who can access the tftpboot directory. Regular security audits should verify that symbolic links and directory structures properly isolate system resources. The vulnerability demonstrates the critical importance of proper privilege separation and access control implementation in network services, particularly those that handle file operations in restricted environments. Additionally, organizations should implement network monitoring to detect unusual file access patterns that might indicate exploitation attempts against this or similar directory traversal vulnerabilities.