CVE-2011-1153 in PHP
Summary
by MITRE
Multiple format string vulnerabilities in phar_object.c in the phar extension in PHP 5.3.5 and earlier allow context-dependent attackers to obtain sensitive information from process memory, cause a denial of service (memory corruption), or possibly execute arbitrary code via format string specifiers in an argument to a class method, leading to an incorrect zend_throw_exception_ex call.
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Analysis
by VulDB Data Team • 10/19/2021
The vulnerability described in CVE-2011-1153 represents a critical format string vulnerability within PHP's phar extension, specifically in the phar_object.c file. This flaw affects PHP versions 5.3.5 and earlier, making it a significant concern for systems running outdated PHP implementations. The vulnerability stems from improper handling of format string specifiers in method arguments, creating opportunities for attackers to manipulate memory access patterns and potentially exploit the underlying system.
The technical implementation of this vulnerability occurs through incorrect zend_throw_exception_ex function calls that fail to properly sanitize input parameters. When attackers provide malicious format string specifiers as arguments to phar class methods, the system processes these inputs without adequate validation, leading to format string exploitation. This type of vulnerability falls under CWE-134, which specifically addresses the use of format strings with user-supplied data, a well-documented weakness in software security practices. The improper handling of format strings creates a pathway for attackers to read arbitrary memory locations, potentially exposing sensitive process information such as stack contents, heap data, or credential material.
The operational impact of this vulnerability extends beyond simple information disclosure to encompass potential system compromise. Attackers can leverage the format string vulnerabilities to cause memory corruption, leading to denial of service conditions that may crash the web server or application processes. More critically, the vulnerability could enable arbitrary code execution, allowing malicious actors to gain unauthorized access to systems running vulnerable PHP implementations. This capability aligns with ATT&CK technique T1059.007, which covers the use of command and scripting interpreter for execution, as attackers could potentially inject and execute malicious code through the compromised PHP environment. The vulnerability's context-dependent nature means that exploitation requires specific conditions and knowledge of the target system's memory layout, but once achieved, the impact can be severe.
Mitigation strategies for CVE-2011-1153 primarily focus on immediate PHP version upgrades to patched releases, as the vulnerability has been addressed in subsequent PHP versions through proper format string handling and input validation. Organizations should implement comprehensive patch management procedures to ensure all PHP installations are updated promptly. Additionally, developers should adopt secure coding practices that prevent format string vulnerabilities by using safe string formatting functions and validating all user inputs before processing. The implementation of proper input sanitization and parameter validation can significantly reduce the attack surface for similar vulnerabilities. System administrators should also consider implementing network segmentation and monitoring to detect potential exploitation attempts, as the vulnerability may manifest through unusual memory access patterns or application crashes that could indicate active exploitation.