Source: security@qnapsecurity.com.tw
A path traversal vulnerability has been reported to affect Qfiling. The remote attackers can then exploit the vulnerability to read the contents of unexpected files or system data. We have already fixed the vulnerability in the following version: Qfiling 3.13.1 and later
Qfiling is vulnerable to a path traversal attack, allowing attackers to read sensitive files and potentially gain unauthorized access to the system. This vulnerability could lead to data breaches and compromise the integrity of the affected device. Immediate patching is crucial to mitigate the risk.
Step 1: Craft Malicious Request: The attacker crafts a malicious request to the Qfiling application, likely through a web interface or API endpoint. This request includes a specially crafted file path designed to exploit the path traversal vulnerability. The path will contain sequences like ../ to move up the directory structure.
Step 2: Input Injection: The malicious file path is injected into a parameter or field of the request that is used to specify a file to be accessed or processed by Qfiling.
Step 3: Path Traversal: The Qfiling application receives the request and, due to insufficient input validation, processes the malicious file path. The application likely concatenates the attacker-controlled path with a base directory without proper sanitization.
Step 4: File Access: The application attempts to access the file specified by the manipulated path. Because the path traversal sequences allow the attacker to navigate outside the intended directory, the application will access the attacker-specified file.
Step 5: Data Exfiltration: The application reads the contents of the unauthorized file and either displays it to the attacker (if the access is through a web interface) or allows the attacker to download the file. This could include sensitive system files, configuration files, or user data.
The vulnerability stems from insufficient input validation within the Qfiling application when handling file paths. Specifically, the application fails to properly sanitize user-supplied input used to access files. This allows an attacker to craft a malicious path containing directory traversal sequences (e.g., ../) to navigate outside the intended directory and access arbitrary files on the server. The root cause is a lack of proper input sanitization and path normalization before accessing the file system. The application likely uses a function that directly concatenates user-controlled input with a base directory path, without checking for or removing path traversal characters. This allows an attacker to specify a path that, when combined with the base directory, resolves to a location outside the intended scope.
While no specific APTs are directly linked to this CVE at this time, path traversal vulnerabilities are commonly exploited by various threat actors. The impact of this vulnerability (data exfiltration) makes it attractive to both financially motivated and state-sponsored actors. This vulnerability is not currently listed on the CISA KEV.
Monitor web server logs for suspicious HTTP requests containing path traversal sequences (e.g., ../).
Analyze network traffic for unusual file access patterns or data exfiltration attempts.
Implement file integrity monitoring to detect unauthorized changes to critical system files.
Review Qfiling application logs for error messages or suspicious activity related to file access.
Use intrusion detection systems (IDS) and intrusion prevention systems (IPS) with signatures designed to detect path traversal attempts.
Upgrade to Qfiling version 3.13.1 or later.
Implement robust input validation to sanitize all user-supplied file paths, ensuring that they do not contain path traversal sequences.
Use a secure file path normalization function to resolve relative paths and prevent access outside the intended directory.
Restrict file access permissions to the minimum necessary for the application to function.
Regularly update all software and firmware to patch known vulnerabilities.
Implement a web application firewall (WAF) to filter malicious requests.
Conduct regular security audits and penetration testing to identify and address vulnerabilities.