CVE-2009-2787 in reputation
Summary
by MITRE
Directory traversal vulnerability in include/reputation/rep_profile.php in the Reputation plugin 2.2.4, 2.2.3, 2.0.4, and earlier for PunBB, when register_globals is enabled and magic_quotes_gpc is disabled, allows remote attackers to include and execute arbitrary local files via a .. (dot dot) in the pun_user[language] parameter.
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Analysis
by VulDB Data Team • 12/07/2024
The vulnerability described in CVE-2009-2787 represents a critical directory traversal flaw within the PunBB Reputation plugin version 2.2.4, 2.2.3, 2.0.4, and earlier versions. This weakness exists in the rep_profile.php file and specifically targets the pun_user[language] parameter handling. The vulnerability is particularly dangerous because it can be exploited when the web server has register_globals enabled and magic_quotes_gpc disabled, creating an environment where user input is directly incorporated into the global namespace without proper sanitization. The flaw allows remote attackers to manipulate file inclusion paths by injecting .. (dot dot) sequences into the parameter, effectively enabling them to traverse the directory structure and access arbitrary local files on the server.
The technical exploitation of this vulnerability occurs through the manipulation of the pun_user[language] parameter, which is processed without adequate validation or sanitization. When register_globals is enabled, user-supplied input becomes directly accessible as global variables, while the absence of magic_quotes_gpc means that special characters are not automatically escaped, creating a perfect storm for path traversal attacks. Attackers can construct malicious payloads that leverage the .. sequences to navigate upward through the directory hierarchy, potentially accessing sensitive files such as configuration files, database credentials, or system files that should remain protected. This vulnerability directly maps to CWE-22, which defines the weakness as improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
The operational impact of this vulnerability is severe and multifaceted, as it can lead to complete system compromise when exploited successfully. An attacker who successfully exploits this vulnerability can execute arbitrary code on the target system, potentially gaining administrative privileges or accessing confidential data. The attack surface extends beyond simple file reading to include full system compromise, especially when combined with other vulnerabilities or when the server configuration allows for code execution. This type of vulnerability can be leveraged for data exfiltration, privilege escalation, or as a stepping stone for further attacks within the network infrastructure. According to the ATT&CK framework, this vulnerability corresponds to T1059.007 for Command and Scripting Interpreter and T1068 for Exploitation for Privilege Escalation, as it enables an attacker to execute arbitrary commands and potentially elevate their privileges within the system.
Mitigation strategies for this vulnerability must address both the immediate code-level issues and the broader server configuration problems. The primary fix involves implementing proper input validation and sanitization for all user-supplied parameters, particularly those used in file inclusion operations. Developers should avoid using user input directly in file path constructions and instead implement whitelisting mechanisms that restrict file access to predetermined, safe values. Server administrators should disable register_globals and enable magic_quotes_gpc to prevent the injection of malicious parameters into the global namespace. Additionally, proper access controls and file permissions should be implemented to restrict access to sensitive system files. The vulnerability also highlights the importance of keeping software components updated, as newer versions of PunBB and its plugins have addressed this specific weakness through improved input validation and secure coding practices. Organizations should conduct regular security assessments and implement security monitoring to detect potential exploitation attempts and ensure that vulnerable systems are promptly patched and updated.