CVE-2007-4658 in PHP
Summary
by MITRE
The money_format function in PHP 5 before 5.2.4, and PHP 4 before 4.4.8, permits multiple (1) %i and (2) %n tokens, which has unknown impact and attack vectors, possibly related to a format string vulnerability.
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Analysis
by VulDB Data Team • 07/25/2019
The CVE-2007-4658 vulnerability resides in the money_format function implementation within PHP versions prior to 5.2.4 for PHP 5 and 4.4.8 for PHP 4. This function is designed to format monetary values according to locale-specific conventions, but it contains a critical flaw in its handling of format specifiers that can lead to unpredictable behavior and potential security implications. The vulnerability specifically manifests when the function encounters multiple instances of %i and %n tokens within the format string, creating a scenario where the standard format string processing mechanisms may be bypassed or manipulated.
The technical flaw stems from insufficient validation and processing of format specifiers within the money_format function, allowing for the presence of multiple identical tokens that could potentially be exploited to manipulate the function's behavior. This issue creates a condition where the format string parsing logic does not properly handle repeated tokens, leading to undefined behavior that could be leveraged by attackers to achieve unintended outcomes. The vulnerability is classified under CWE-134 which specifically addresses the use of format strings with user-supplied data, and it aligns with ATT&CK technique T1059.007 for format string vulnerabilities and command injection scenarios.
The operational impact of this vulnerability extends beyond simple formatting errors, as it could potentially enable attackers to manipulate memory layout or execute arbitrary code depending on the specific implementation details and system configuration. When user-supplied data is processed through the money_format function without proper sanitization, malicious input containing multiple %i or %n tokens could cause the application to behave unpredictably, potentially leading to information disclosure, denial of service, or even remote code execution in certain circumstances. The unknown impact and attack vectors mentioned in the original description highlight the complexity and potential severity of format string vulnerabilities in this context.
Mitigation strategies for CVE-2007-4658 require immediate patching of affected PHP installations to versions 5.2.4 or later for PHP 5, and 4.4.8 or later for PHP 4, as these releases contain the necessary fixes to properly handle format specifiers. Organizations should also implement strict input validation and sanitization measures when processing monetary data, avoiding direct use of user-supplied strings in format functions. Additionally, security monitoring should be enhanced to detect unusual patterns in monetary formatting operations that might indicate exploitation attempts. The vulnerability demonstrates the critical importance of proper format string handling in programming languages and underscores the need for comprehensive security testing of core library functions that process user input.