CVE-2007-5100 in PhpBB Plus
Summary
by MITRE
Multiple PHP remote file inclusion vulnerabilities in phpBB Plus 1.53, and 1.53a before 20070922, when register_globals is enabled, allow remote attackers to execute arbitrary PHP code via a URL in the phpbb_root_path parameter to (1) language/lang_german/lang_admin_album.php, (2) language/lang_english/lang_main_album.php, and (3) language/lang_english/lang_admin_album.php, different vectors than CVE-2007-5009.
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Analysis
by VulDB Data Team • 08/17/2022
The vulnerability described in CVE-2007-5100 represents a critical remote file inclusion flaw affecting phpBB Plus versions 1.53 and 1.53a prior to the 20070922 patch release. This vulnerability specifically exploits the insecure handling of user-supplied input when the PHP configuration parameter register_globals is enabled, creating a pathway for remote attackers to execute arbitrary PHP code on vulnerable systems. The affected files demonstrate a pattern of improper input validation where the phpbb_root_path parameter is directly incorporated into file inclusion operations without adequate sanitization or validation measures.
The technical exploitation mechanism relies on the dangerous interaction between register_globals and user-controllable parameters within the application's codebase. When register_globals is enabled, PHP automatically creates global variables from GET, POST, and cookie data, effectively merging user input directly into the global namespace. This configuration, combined with the vulnerable file inclusion patterns in the album language administration files, allows attackers to inject malicious URLs that get evaluated as PHP code during the file inclusion process. The three specific files targeted include language/lang_german/lang_admin_album.php, language/lang_english/lang_main_album.php, and language/lang_english/lang_admin_album.php, each presenting distinct attack vectors that leverage the same underlying vulnerability.
This vulnerability falls under the CWE-88 category of Improper Neutralization of Argument Delimiters in a Command, specifically manifesting as a remote code execution vector through file inclusion mechanisms. The operational impact is severe as it provides attackers with complete control over the affected web server, enabling them to execute arbitrary commands, access sensitive data, and potentially establish persistent backdoors. The vulnerability differs from CVE-2007-5009 in its specific attack vectors and affected files, yet shares the same fundamental root cause of insecure file inclusion practices. Organizations running vulnerable versions of phpBB Plus face significant risk of compromise, particularly when the server configuration has register_globals enabled, which was common in older PHP installations and legacy systems.
The remediation approach requires immediate patching of the phpBB Plus application to the latest available version that addresses this vulnerability. Additionally, administrators should disable register_globals in their PHP configuration files, as this setting fundamentally undermines web application security by creating dangerous automatic variable creation from user input. Network-level mitigations such as web application firewalls can provide temporary protection by filtering suspicious URL patterns, though these measures should not replace proper code-level fixes. The vulnerability highlights the critical importance of input validation and proper secure coding practices, particularly in applications that handle user-supplied data for file operations. Organizations should also implement comprehensive security monitoring to detect potential exploitation attempts and conduct regular security audits to identify similar insecure coding patterns that may exist in other application components.