CVE-2011-1460 in Chrome
Summary
by MITRE
WebKit in Google Chrome before Blink M11 contains a bad cast to RenderBlock when anonymous blocks are renderblocks.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 02/04/2024
The vulnerability identified as CVE-2011-1460 represents a critical type confusion issue within the WebKit rendering engine that powers Google Chrome browsers prior to the Blink rendering engine transition. This flaw exists in the handling of anonymous blocks within the rendering pipeline, specifically when the system attempts to cast objects to RenderBlock types during the document rendering process. The issue stems from improper type checking and validation mechanisms that fail to properly distinguish between different object types in the rendering hierarchy, creating a dangerous condition where memory corruption can occur through incorrect type casting operations.
The technical implementation of this vulnerability involves the WebKit engine's rendering subsystem where anonymous blocks - which are structural elements created automatically by the browser when dealing with malformed HTML or complex CSS layouts - are processed through a casting mechanism that does not adequately validate the target type. When the rendering engine encounters a scenario where anonymous blocks need to be converted or cast to RenderBlock objects, it performs an unsafe cast operation that bypasses normal type checking procedures. This type confusion allows attackers to manipulate the memory layout and potentially execute arbitrary code by carefully crafting HTML content that triggers the vulnerable code path.
The operational impact of CVE-2011-1460 extends beyond simple rendering failures, as it represents a potential remote code execution vulnerability that could be exploited by malicious actors. The vulnerability is particularly dangerous because it operates within the core rendering engine where all web content is processed, making it an attractive target for attackers seeking to compromise user systems. The flaw essentially allows for memory corruption that could lead to privilege escalation, browser sandbox bypassing, and ultimately full system compromise. This aligns with ATT&CK technique T1059.003 for remote code execution through browser exploits, and maps to CWE-121 for buffer overflow conditions that can occur due to improper memory management in type conversion scenarios.
Mitigation strategies for this vulnerability require immediate browser updates to versions that have implemented proper type validation and casting safeguards. The fix typically involves adding robust type checking mechanisms before any casting operations occur, ensuring that objects are properly validated against their expected types before conversion. Security researchers recommend that organizations implement network-level protections such as content security policies and sandboxing measures to limit the potential impact of exploitation attempts. Additionally, user education regarding safe browsing practices and the importance of keeping browser software updated remains critical in defending against this class of vulnerabilities. The vulnerability serves as a prime example of why proper memory management and type safety are essential in browser engine development, as highlighted in industry best practices for secure software development and the OWASP Top Ten security risks.