CVE-2011-3182 in PHP
Summary
by MITRE
PHP before 5.3.7 does not properly check the return values of the malloc, calloc, and realloc library functions, which allows context-dependent attackers to cause a denial of service (NULL pointer dereference and application crash) or trigger a buffer overflow by leveraging the ability to provide an arbitrary value for a function argument, related to (1) ext/curl/interface.c, (2) ext/date/lib/parse_date.c, (3) ext/date/lib/parse_iso_intervals.c, (4) ext/date/lib/parse_tz.c, (5) ext/date/lib/timelib.c, (6) ext/pdo_odbc/pdo_odbc.c, (7) ext/reflection/php_reflection.c, (8) ext/soap/php_sdl.c, (9) ext/xmlrpc/libxmlrpc/base64.c, (10) TSRM/tsrm_win32.c, and (11) the strtotime function.
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Analysis
by VulDB Data Team • 11/25/2024
The vulnerability described in CVE-2011-3182 represents a critical memory management flaw in PHP versions prior to 5.3.7 that stems from inadequate error handling in fundamental allocation functions. This issue affects core PHP components across multiple extensions and modules, creating a widespread attack surface that can be exploited to compromise system stability and application availability. The flaw manifests when PHP fails to properly validate the return values from malloc, calloc, and realloc system calls, which are essential for dynamic memory allocation in C-based applications. This oversight creates conditions where malicious input can lead to unpredictable memory states and system instability.
The technical implementation of this vulnerability involves several key attack vectors within PHP's core libraries and extensions. The affected files include ext/curl/interface.c which handles cURL operations, ext/date/lib components that manage date parsing functions, ext/pdo_odbc/pdo_odbc.c for database connectivity, ext/reflection/php_reflection.c for introspection capabilities, ext/soap/php_sdl.c for web services, ext/xmlrpc/libxmlrpc/base64.c for XML-RPC processing, TSRM/tsrm_win32.c for thread safety, and the strtotime function itself. These locations represent critical points in PHP's execution flow where memory allocation occurs during normal operation, making them prime targets for exploitation. The vulnerability specifically leverages the ability of attackers to provide arbitrary values that can cause these allocation functions to return NULL pointers or invalid memory addresses.
The operational impact of CVE-2011-3182 extends beyond simple denial of service to potentially enable more sophisticated attacks through buffer overflow conditions. When allocation functions fail to properly check return values, context-dependent attackers can craft inputs that cause NULL pointer dereferences, leading to application crashes and system instability. More critically, the vulnerability can trigger buffer overflows when invalid memory addresses are used, potentially allowing attackers to execute arbitrary code or escalate privileges. This vulnerability aligns with CWE-754, which describes improper check for a standard error condition, and represents a classic example of how memory management failures can create cascading security issues in application frameworks. The attack surface covers a broad range of PHP applications that rely on these core functions, from web applications to command-line tools and system utilities.
Mitigation strategies for this vulnerability require immediate patching of PHP installations to versions 5.3.7 or later where the memory allocation error handling has been corrected. System administrators should implement comprehensive monitoring for abnormal application behavior and memory allocation patterns that might indicate exploitation attempts. The remediation process must include thorough testing of patched environments to ensure no regression issues have been introduced. Organizations should also consider implementing input validation controls at multiple layers to reduce the effectiveness of potential exploitation attempts, though the primary defense remains the official PHP security patch. The vulnerability demonstrates the critical importance of proper error handling in system-level programming and highlights why memory safety should be a fundamental consideration in all software development practices. This issue serves as a reminder of the potential for seemingly minor implementation flaws to create significant security risks in widely deployed software components.