CVE-1999-0495 in Host
Summary
by MITRE
A remote attacker can gain access to a file system using .. (dot dot) when accessing SMB shares.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability described in CVE-1999-0495 represents a classic path traversal issue affecting Server Message Block SMB protocol implementations. This security flaw allows remote attackers to access files and directories outside of the intended share boundaries by exploiting directory traversal sequences using the .. (dot dot) notation. The vulnerability specifically impacts SMB servers that do not properly validate path components when processing file access requests, creating a pathway for unauthorized access to system resources that should remain protected.
The technical implementation of this vulnerability stems from inadequate input validation within SMB protocol handling mechanisms. When an SMB client sends a request containing directory traversal sequences such as ..\..\\ or ../../../, the vulnerable server fails to properly sanitize these path components before processing file access operations. This allows attackers to navigate up directory trees and access files that are not intended to be reachable through normal SMB share access. The flaw exists at the application layer where SMB protocol handlers do not adequately enforce proper path resolution and validation, creating a direct pathway for privilege escalation and data exfiltration.
The operational impact of CVE-1999-0495 is substantial and multifaceted, affecting organizations with SMB-based file sharing infrastructure. Attackers can leverage this vulnerability to access sensitive system files, configuration data, and user documents that reside outside of designated share boundaries. This could lead to complete system compromise, data theft, and unauthorized administrative access to network resources. The vulnerability is particularly dangerous in enterprise environments where SMB shares are commonly used for file distribution and collaboration, as it allows attackers to bypass normal access controls and potentially gain access to critical system files, passwords, or other sensitive information stored on the server.
Mitigation strategies for this vulnerability should include immediate implementation of SMB protocol security patches and updates from vendors, along with network segmentation to limit SMB access to trusted environments. Organizations should implement proper SMB configuration settings that disable unnecessary file sharing features and enforce strict access controls. Network monitoring should be enhanced to detect suspicious SMB traffic patterns, particularly those involving directory traversal sequences. According to CWE standards, this vulnerability maps to CWE-22 Path Traversal, which is classified as a critical security weakness requiring immediate remediation. The ATT&CK framework categorizes this as a privilege escalation technique under the T1077.001 sub-technique for Windows file system access, making it a significant concern for enterprise security teams. Regular security audits of SMB implementations and comprehensive vulnerability assessments should be conducted to ensure proper protection against similar path traversal vulnerabilities in network infrastructure.