Source: cve@mitre.org
Directory traversal vulnerability in Phorum 3.0.7 allows remote Phorum administrators to read arbitrary files via ".." (dot dot) sequences in the default .langfile name field in the Master Settings administrative function, which causes the file to be displayed in admin.php3.
Phorum 3.0.7 suffers from a critical directory traversal vulnerability, allowing remote attackers with administrative privileges to read arbitrary files on the server. This flaw enables attackers to potentially access sensitive information, including configuration files and user credentials, leading to complete system compromise.
Step 1: Access Admin Interface: The attacker must first authenticate as a Phorum administrator. This typically involves knowing the administrator username and password.
Step 2: Navigate to Master Settings: The attacker accesses the Master Settings administrative function within Phorum's admin interface (admin.php3).
Step 3: Craft Malicious Payload: The attacker crafts a malicious value for the .langfile parameter. This value includes .. sequences to traverse the directory structure and target a specific file (e.g., /etc/passwd or a configuration file).
Step 4: Submit Payload: The attacker submits the crafted .langfile value through the admin interface.
Step 5: File Retrieval: The server, due to the lack of input validation, processes the malicious .langfile value. The server attempts to open the file specified by the crafted path. The contents of the targeted file are then displayed within the admin.php3 interface, allowing the attacker to read the file's contents.
The vulnerability stems from insufficient input validation within the Phorum 3.0.7 Master Settings administrative function. Specifically, the software fails to properly sanitize the .langfile parameter, which is used to specify the language file to load. By injecting a crafted value containing .. (dot-dot) sequences, an attacker can traverse the directory structure and access files outside of the intended scope. The root cause is a lack of proper path normalization and input validation before the file is opened and read. The application trusts the user-supplied input without verifying that it resides within the expected directory.
While no specific APTs are directly linked to this CVE, the ease of exploitation makes it attractive to a wide range of attackers, including those seeking initial access. The vulnerability could be used as a stepping stone for further attacks. Not listed on CISA KEV.
Network traffic analysis: Examine HTTP requests to admin.php3 for suspicious .langfile parameter values containing .. sequences.
File system monitoring: Monitor file access logs for unexpected access to sensitive files (e.g., /etc/passwd, configuration files) by the web server process.
Web server logs: Analyze web server access logs for requests to admin.php3 with unusual parameters or file access patterns.
Intrusion Detection Systems (IDS): Implement IDS rules to detect attempts to exploit this vulnerability based on the malicious payload.
Upgrade to a patched version of Phorum (if available).
Implement input validation: Ensure that the .langfile parameter is properly sanitized and validated to prevent directory traversal. This includes checking for .. sequences and ensuring the path is within the expected directory.
Restrict administrative access: Limit access to the Phorum administrative interface to trusted IP addresses or networks.
Apply the principle of least privilege: Ensure the web server process has minimal necessary permissions.
Regularly audit and monitor web server logs for suspicious activity.
Implement a Web Application Firewall (WAF): A WAF can help to filter malicious requests and prevent exploitation attempts.