CVE-2014-9912 in PHP
Summary
by MITRE
The get_icu_disp_value_src_php function in ext/intl/locale/locale_methods.c in PHP before 5.3.29, 5.4.x before 5.4.30, and 5.5.x before 5.5.14 does not properly restrict calls to the ICU uresbund.cpp component, which allows remote attackers to cause a denial of service (buffer overflow) or possibly have unspecified other impact via a locale_get_display_name call with a long first argument.
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Analysis
by VulDB Data Team • 10/27/2022
The vulnerability identified as CVE-2014-9912 represents a critical buffer overflow flaw within PHP's internationalization extension, specifically affecting versions prior to the patched releases. This issue resides in the get_icu_disp_value_src_php function located in ext/intl/locale/locale_methods.c, which interfaces with the ICU (International Components for Unicode) library's uresbund.cpp component. The vulnerability manifests when the locale_get_display_name function is invoked with an excessively long first argument, creating a scenario where input validation fails to properly constrain the data passed to the underlying ICU library.
The technical exploitation of this vulnerability occurs through improper input sanitization within PHP's internationalization framework. When a malicious user provides an unusually long string as the first parameter to locale_get_display_name, the function fails to adequately validate the input length before passing it to the ICU library's resource bundle handling component. This oversight allows the attacker to trigger a buffer overflow condition in the uresbund.cpp file, which is part of the ICU library responsible for managing locale data and resource bundles. The buffer overflow can potentially lead to memory corruption that may result in denial of service conditions or more severe consequences depending on the execution context.
From an operational impact perspective, this vulnerability poses significant risks to web applications that rely on PHP's internationalization capabilities and handle user-provided locale data. The vulnerability can be exploited remotely without authentication, making it particularly dangerous for publicly accessible web services. Attackers can leverage this flaw to cause service interruptions through denial of service attacks, potentially rendering web applications unavailable to legitimate users. The unspecified other impacts mentioned in the CVE description suggest that in certain circumstances, this vulnerability could potentially be escalated to achieve arbitrary code execution or other malicious outcomes, though this requires additional exploitation vectors.
The vulnerability aligns with CWE-121, which describes heap-based buffer overflow conditions, and represents a classic example of improper input validation in library interfaces. According to ATT&CK framework, this vulnerability maps to T1499.004, which covers network denial of service attacks, and potentially T1059, representing command and scripting interpreter techniques if exploitation leads to code execution. Organizations using affected PHP versions should prioritize immediate patching to mitigate this risk, as the vulnerability affects multiple major PHP release lines including 5.3, 5.4, and 5.5 series. The recommended mitigation strategy involves upgrading to PHP versions 5.3.29, 5.4.30, or 5.5.14 respectively, which contain the necessary fixes to properly constrain input parameters before passing them to the ICU library components. Additionally, implementing proper input validation at the application level and monitoring for unusual locale data patterns can serve as additional defensive measures against potential exploitation attempts.