CVE-2005-1047 in phpBB
Summary
by MITRE
Meilad File upload script (up.php) mod for phpBB 2.0.x does not properly limit the types of files that can be uploaded, which allows remote authenticated users to execute arbitrary commands by uploading PHP files, then directly requesting them from the uploads directory.
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Analysis
by VulDB Data Team • 05/31/2019
The vulnerability identified as CVE-2005-1047 affects the Meilad File upload script component within phpBB 2.0.x forums, representing a critical security flaw that enables authenticated attackers to achieve remote command execution through improper file type validation. This vulnerability resides in the up.php module which is part of the phpBB 2.0.x ecosystem, specifically targeting the file upload functionality that lacks proper input sanitization and validation mechanisms. The flaw stems from the absence of strict file type checking that would normally prevent the upload of executable scripts, particularly PHP files that could be executed by the web server. The vulnerability is classified under CWE-434 which addresses the insecure upload of executable files, and aligns with ATT&CK technique T1190 for exploiting vulnerabilities in web applications.
The technical exploitation of this vulnerability requires an authenticated user within the phpBB forum system, as the upload functionality is restricted to registered members. Attackers can bypass the intended file type restrictions by uploading PHP shell scripts or other malicious code files through the vulnerable up.php script. Once successfully uploaded to the server's file system, these files can be directly accessed by requesting them from the uploads directory, thereby enabling arbitrary command execution on the web server. The vulnerability is particularly dangerous because it leverages the legitimate file upload mechanism of the forum software, making it difficult to detect through standard security monitoring approaches. The lack of proper file extension validation, content type checking, or file signature verification creates an exploitable path where attackers can execute code with the privileges of the web server process.
The operational impact of CVE-2005-1047 extends beyond simple unauthorized access to include complete system compromise and potential data breaches. Successful exploitation allows attackers to establish persistent backdoors, escalate privileges, and gain access to sensitive forum data including user credentials, private messages, and potentially underlying database information. The vulnerability can be exploited to create a foothold for further attacks within the network, as compromised forum servers often serve as launching points for broader security breaches. Organizations running vulnerable phpBB installations face significant risk of reputational damage, regulatory compliance violations, and potential legal consequences due to data exposure. The vulnerability also demonstrates the importance of proper input validation and the principle of least privilege in web application security, as the flaw could have been prevented through basic security coding practices.
Mitigation strategies for CVE-2005-1047 require immediate action including the upgrade to patched versions of phpBB 2.0.x or the complete removal of the vulnerable Meilad File upload script module. Organizations should implement strict file type validation that checks both file extensions and MIME types against a whitelist of allowed formats, while also ensuring that uploaded files are not executable. Server-side configuration changes should include restricting write permissions to upload directories and implementing proper file access controls that prevent direct execution of uploaded files. Network-level protections such as web application firewalls and intrusion detection systems can help detect and block attempts to exploit this vulnerability. Security monitoring should include regular vulnerability scanning and file integrity checks to identify unauthorized file uploads. The remediation process must also include user access review and privilege management to ensure that only authorized personnel have upload capabilities, aligning with the security principle that authentication alone is insufficient without proper authorization controls. Organizations should also consider implementing automated patch management processes to ensure timely application of security updates and prevent similar vulnerabilities from arising in other components of their web infrastructure.