CVE-2020-29026 in GateManager
Summary
by MITRE • 02/16/2021
A directory traversal vulnerability exists in the file upload function of the GateManager that allows an authenticated attacker with administrative permissions to read and write arbitrary files in the Linux file system. This issue affects: GateManager all versions prior to 9.2c.
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Analysis
by VulDB Data Team • 03/01/2021
The directory traversal vulnerability identified as CVE-2020-29026 represents a critical security flaw within the GateManager application ecosystem that fundamentally undermines file system integrity and access controls. This vulnerability specifically targets the file upload functionality of the GateManager system, which serves as a critical component in network access control and authentication management. The flaw exists in all versions of GateManager prior to 9.2c, indicating a prolonged period during which organizations using this software were exposed to significant risk. The vulnerability's impact is particularly severe because it requires only administrative authentication credentials to exploit, meaning that a single compromised administrative account could provide full system compromise. This weakness directly violates fundamental security principles of least privilege and access control, as legitimate administrative users can leverage this vulnerability to bypass normal file system restrictions and gain unauthorized access to critical system files.
The technical implementation of this vulnerability stems from inadequate input validation within the file upload mechanism of GateManager. When an authenticated administrative user attempts to upload files through the system, the application fails to properly sanitize or validate file paths and names, allowing attackers to manipulate the upload process to traverse directories beyond the intended upload location. This type of vulnerability maps directly to CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw typically occurs when user-supplied data is directly incorporated into file system operations without proper validation or sanitization, creating opportunities for attackers to manipulate file paths through sequences such as "../" or similar directory navigation patterns. The vulnerability operates at the application layer, specifically within the file handling and processing components that should enforce strict boundary checks and path validation.
The operational impact of this vulnerability extends far beyond simple unauthorized file access, creating a comprehensive attack surface that can lead to complete system compromise and data exfiltration. An attacker with administrative privileges can leverage this vulnerability to read sensitive system files including configuration files, database credentials, application source code, and system logs that may contain authentication tokens or other sensitive information. Additionally, the ability to write arbitrary files allows for persistent backdoor installation, privilege escalation, and potential lateral movement within the network environment. This vulnerability creates opportunities for attackers to establish persistent access, modify system binaries, or inject malicious code that can remain undetected for extended periods. The attack vector is particularly concerning because it requires minimal privilege escalation beyond existing administrative access, making it an attractive target for both internal and external attackers seeking to maintain long-term access to network infrastructure. The vulnerability's exploitation directly aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1078.004 for Valid Accounts, as it leverages legitimate administrative accounts to execute malicious file operations.
Organizations affected by this vulnerability should immediately implement multiple layers of mitigation strategies to protect their systems and infrastructure. The primary and most critical mitigation involves upgrading to GateManager version 9.2c or later, which contains the necessary patches to address the directory traversal flaw. System administrators should also implement additional security controls including restrictive file upload policies, comprehensive input validation mechanisms, and strict file path normalization procedures. Network segmentation and access control measures should be enhanced to limit the scope of potential impact even if an attacker successfully exploits the vulnerability. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities within the broader application ecosystem. The implementation of file integrity monitoring solutions can help detect unauthorized file modifications, while logging and monitoring systems should be configured to alert on suspicious file system access patterns. Security awareness training for administrative users should emphasize the importance of maintaining secure administrative accounts and recognizing potential signs of compromise. Additionally, organizations should consider implementing web application firewalls and runtime application self-protection mechanisms to provide additional defense-in-depth measures against similar path traversal attacks.