Advisory ID: ngCERT-2025-050014
Probability: High
Damage: Critical
Platform(s): Web Application
SUMMARY
ngCERT is aware of a critical vulnerability referred to as the Directory Traversal vulnerability. Directory Traversal, also known as Path Traversal or directory climbing, is a web application server flaw that enables attackers to gain unauthorized access to files and directories on a server by manipulating file paths. This flaw arises from weak input validation, which allows attackers to navigate outside the designated directory structure. The severity of the impact can vary, however, it often results in significant consequences such as data breaches or unauthorised system access. Additionally, following best practices like regular vulnerability testing, code audits, and implementing access control is essential for preventing exploitation.
DESCRIPTION
Directory Traversal is a security vulnerability in web application servers caused by an HTTP exploit. It occurs due to weak input validation or insecure file-handling practices. This flaw allows an attacker to manipulate file paths, gaining access to directories and files outside the designated directory structure on a web server. Malicious attackers exploit this vulnerability by manipulating URL paths or parameters through the server’s file system by taking advantage of sequences like “../” (Unix) or “..\” (Windows) and retrieve sensitive information, such as configuration or password files, or other critical data. Directory Traversal can lead to the exposure of sensitive system or application details, unauthorized access to restricted files, and the potential for further attacks that compromise the server or other connected systems.
CONSEQUENCES
Falling prey to these attacks could potentially lead to:
- Authentication Bypass: Directory traversal can be used to bypass authentication mechanisms and gain unauthorized privileges.
- Data Exposure: Confidential information, such as configuration files or user data, may be exposed.
- Unauthorized Access: Attackers gain access to sensitive files and directories.
- Data Manipulation: Attackers can modify or delete critical files, leading to service disruptions.
SOLUTION/MITIGATION
ngCERT recommends the following:
- Minimize network exposure for all control system devices and ensure that they are not accessible from the Internet.
- Implement a location control system, networks and remote devices behind firewalls, and isolate them from the business network.
- When remote access is required, use secure methods, such as Virtual Private Networks (VPNs), recognizing that VPNs may have vulnerabilities and should be updated to the most current version. Also, recognize that a VPN is only as secure as the connected devices.
- Perform proper impact analysis and risk assessment before deploying defensive measures.
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