CVE-2007-2103 in forum
Summary
by MITRE
Multiple PHP remote file inclusion vulnerabilities in my little forum 1.7 allow remote attackers to execute arbitrary PHP code via a URL in the lang parameter to (1) admin.php and (2) timedifference.php.
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Analysis
by VulDB Data Team • 08/29/2018
The vulnerability described in CVE-2007-2103 represents a critical remote code execution flaw affecting my little forum version 1.7. This issue manifests through multiple remote file inclusion vulnerabilities that specifically target the lang parameter in two key administrative scripts. The vulnerability falls under the category of insecure direct object references and improper input validation, creating a pathway for malicious actors to inject and execute arbitrary PHP code on the target system. The affected files admin.php and timedifference.php demonstrate a fundamental failure in parameter sanitization, allowing attackers to manipulate the language selection mechanism into loading external malicious code.
The technical exploitation of this vulnerability occurs through the manipulation of the lang parameter which is used to determine which language file should be included in the application's execution context. When an attacker supplies a URL as the value for this parameter, the application's flawed input handling allows the system to treat this URL as a legitimate file path for inclusion. This creates a classic remote file inclusion (RFI) vulnerability where the attacker can specify any remote web server containing malicious PHP code, which then gets executed within the context of the web application. The vulnerability is particularly dangerous because it affects administrative scripts that typically run with elevated privileges, potentially allowing full system compromise. This flaw directly maps to CWE-88, which describes improper neutralization of special elements used in an expression, and CWE-94, which addresses execution of arbitrary code due to insufficient input validation.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with complete control over the affected web server. Once successfully exploited, an attacker could install backdoors, steal sensitive data, modify forum content, or use the compromised server as a launch point for further attacks against the internal network. The vulnerability affects the administrative functionality of the forum, potentially allowing attackers to modify user permissions, delete content, or even completely compromise the application's integrity. This type of vulnerability is particularly concerning in web applications where administrative functions are accessible to authenticated users, as it could enable privilege escalation attacks that leverage the administrative scripts. The attack surface is further expanded by the fact that these vulnerabilities exist in files that may be accessed by legitimate administrative functions, making detection more difficult.
Mitigation strategies for this vulnerability should focus on immediate input validation and parameter sanitization measures. The most effective approach involves implementing strict validation of all input parameters, particularly those used in file inclusion operations, ensuring that only predefined, whitelisted values are accepted. This aligns with the principle of least privilege and input validation practices recommended by the OWASP Top Ten. Administrators should also implement proper access controls and ensure that administrative scripts are not directly accessible to unauthenticated users. The application should be updated to a patched version that properly validates and sanitizes all input parameters before processing. Network-based mitigations such as web application firewalls can help detect and block malicious requests, while regular security audits and code reviews should be conducted to identify similar vulnerabilities in other parts of the application. Additionally, the principle of defense in depth should be applied by implementing proper logging and monitoring of administrative functions to detect unauthorized access attempts. This vulnerability exemplifies why secure coding practices are essential, particularly in applications that handle user input and perform dynamic file operations, as it demonstrates how seemingly minor input validation failures can lead to complete system compromise. The ATT&CK framework categorizes this as a technique for Command and Control through the use of remote file inclusion to establish persistent access to compromised systems.