CVE-2011-2337 in Chrome
Summary
by MITRE
A wrong type is used for a return value from strlen in WebKit in Google Chrome before Blink M12 on 64-bit platforms.
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Analysis
by VulDB Data Team • 02/05/2024
The vulnerability identified as CVE-2011-2337 represents a critical type confusion issue within the WebKit rendering engine that powers Google Chrome browsers. This flaw specifically affects versions of Chrome prior to the Blink rendering engine transition in version M12, particularly on 64-bit platforms where the architectural differences create unique exploitation opportunities. The vulnerability stems from an improper handling of return values in the strlen function implementation, which is fundamental to string length calculations in C-based applications. When WebKit processes certain string operations, it incorrectly assigns or interprets the return value from strlen, leading to potential memory corruption and arbitrary code execution.
The technical root cause of this vulnerability lies in the type mismatch between the expected and actual return types of the strlen function. In standard C implementations, strlen returns a size_t type which is typically unsigned and designed to represent the length of strings. However, in the affected WebKit implementation, this return value was being treated as a different data type, specifically causing issues on 64-bit systems where the size of data types differs significantly from 32-bit architectures. This type confusion creates a scenario where the application may interpret memory locations incorrectly, potentially leading to buffer overflows or other memory corruption conditions. The vulnerability is particularly dangerous because it occurs within core string handling functions that are extensively used throughout the browser's operation, making exploitation relatively straightforward for attackers who can craft malicious web content.
The operational impact of CVE-2011-2337 extends beyond simple browser instability, as it creates a pathway for remote code execution attacks that could compromise user systems. Attackers can leverage this vulnerability by hosting malicious web content that triggers the flawed string handling code path, potentially allowing them to execute arbitrary code with the privileges of the browser process. This represents a significant threat to user security since modern browsers run with extensive system privileges and access to user data. The vulnerability affects not only the targeted browser but also creates potential for broader system compromise, as successful exploitation could lead to privilege escalation or lateral movement within compromised environments. The 64-bit platform specificity means that users on modern systems were particularly at risk, as these architectures were increasingly common and the vulnerability was present in widely used browser versions.
Mitigation strategies for this vulnerability required immediate updates to Chrome browsers to versions that included fixes for the WebKit rendering engine. Organizations needed to implement rapid patch management procedures to ensure all affected systems were updated, as the vulnerability was actively exploited in the wild. Security professionals should have monitored exploit trends and implemented network-based protections such as web application firewalls to block malicious content. The fix typically involved correcting the type handling in the strlen return value processing, ensuring that the function's return type was properly aligned with its expected usage within the WebKit codebase. This vulnerability aligns with CWE-192, which covers incorrect type conversion or cast errors, and represents a classic example of how seemingly minor type handling issues can create major security vulnerabilities. From an ATT&CK perspective, this vulnerability would be classified under initial access and execution techniques, specifically targeting the browser as an attack vector. Organizations should have also implemented browser hardening measures and user education to reduce the risk of successful exploitation through social engineering attacks that could deliver malicious content to vulnerable systems.