CVE-2009-2224 in AN Guestbook
Summary
by MITRE
Directory traversal vulnerability in ang/shared/flags.php in AN Guestbook 0.7.8, when register_globals is enabled, allows remote attackers to read arbitrary files via a .. (dot dot) in the g_lang parameter.
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Analysis
by VulDB Data Team • 12/01/2024
The vulnerability identified as CVE-2009-2224 represents a critical directory traversal flaw within the AN Guestbook 0.7.8 web application. This weakness specifically resides in the ang/shared/flags.php component where the application fails to properly sanitize user input parameters. The vulnerability becomes exploitable when the PHP configuration setting register_globals is enabled, creating a dangerous condition where user-supplied data can directly influence the application's internal variable scope. The affected parameter g_lang serves as the attack vector, allowing malicious actors to manipulate file inclusion paths through the use of .. (dot dot) sequences in the parameter value.
The technical implementation of this vulnerability stems from inadequate input validation and improper file handling mechanisms within the guestbook application. When register_globals is enabled, the application's configuration creates an environment where external parameters can be directly injected into the script's global namespace. This configuration flaw, combined with the lack of proper sanitization for the g_lang parameter, enables attackers to traverse the file system hierarchy by appending directory traversal sequences to the parameter value. The vulnerability essentially allows an attacker to bypass normal file access controls and potentially read sensitive files that should remain protected from unauthorized access.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with the capability to access arbitrary files on the server hosting the vulnerable application. This could potentially expose sensitive configuration files, database credentials, application source code, or other confidential data that might be stored within the web server's file system. The attack scenario typically involves an attacker constructing a malicious URL with the g_lang parameter containing directory traversal sequences, which when processed by the vulnerable script, results in unauthorized file access. This type of vulnerability aligns with CWE-22, which specifically addresses improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks.
Security professionals should note that this vulnerability demonstrates the critical importance of proper input validation and the dangerous implications of legacy PHP configurations such as register_globals. The ATT&CK framework categorizes this vulnerability under privilege escalation and defense evasion techniques, as attackers can leverage it to gain deeper system access. Organizations should immediately disable register_globals in their PHP configurations and implement proper parameter sanitization to prevent exploitation. Additionally, the vulnerability highlights the need for regular security assessments of web applications, particularly legacy systems that may contain deprecated configurations or unpatched code. The remediation process involves either patching the application to properly validate input parameters or disabling the vulnerable functionality entirely while ensuring that proper access controls are in place to prevent unauthorized file access.