CVE-2010-4409 in PHP
Summary
by MITRE
Integer overflow in the NumberFormatter::getSymbol (aka numfmt_get_symbol) function in PHP 5.3.3 and earlier allows context-dependent attackers to cause a denial of service (application crash) via an invalid argument.
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Analysis
by VulDB Data Team • 01/26/2025
The vulnerability identified as CVE-2010-4409 represents a critical integer overflow flaw within PHP's internationalization component, specifically affecting versions 5.3.3 and earlier. This issue resides in the NumberFormatter::getSymbol function, which is part of the php_intl extension responsible for handling locale-specific number formatting operations. The vulnerability manifests when the function processes invalid arguments, creating a condition where integer arithmetic operations exceed their maximum representable values, leading to unpredictable behavior and system instability.
The technical exploitation of this vulnerability occurs through careful manipulation of input parameters passed to the NumberFormatter::getSymbol function, which is commonly used in applications that require proper number formatting for different locales. When an attacker provides crafted invalid arguments, the integer overflow causes memory corruption that can result in application crashes or complete denial of service conditions. This flaw operates at the intersection of software security and internationalization handling, demonstrating how seemingly benign formatting functions can become attack vectors when proper input validation is lacking.
From an operational impact perspective, this vulnerability poses significant risks to web applications that rely on PHP's internationalization capabilities for handling user data, financial calculations, or any scenario requiring locale-aware number formatting. The denial of service condition can affect entire application availability, particularly in high-traffic environments where multiple concurrent requests might trigger the overflow condition. Security researchers have classified this issue as a medium to high severity vulnerability due to its potential for causing system instability and the relative ease with which attackers can craft malicious inputs.
The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions, and represents a classic example of how integer arithmetic errors can be exploited in application-level code. From an attack framework perspective, this flaw can be categorized under the MITRE ATT&CK technique T1499.004 for network denial of service, as it enables attackers to disrupt service availability. Organizations utilizing affected PHP versions should prioritize immediate patching and implement input validation measures to prevent malicious arguments from reaching the vulnerable function, while also considering runtime monitoring to detect potential exploitation attempts.
This vulnerability highlights the importance of robust input validation in internationalization libraries and demonstrates the critical nature of proper integer handling in software development practices. The impact extends beyond simple application crashes to potentially enable more sophisticated attacks if combined with other vulnerabilities in the same codebase. System administrators and security teams should conduct comprehensive vulnerability assessments to identify all instances where NumberFormatter functions are used, ensuring that proper error handling and input sanitization are implemented throughout the application stack.