CVE-2011-1285 in Chrome
Summary
by MITRE
The regular-expression functionality in Google Chrome before 10.0.648.127 does not properly implement reentrancy, which allows remote attackers to cause a denial of service (memory corruption) or possibly have unspecified other impact via unknown vectors.
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Analysis
by VulDB Data Team • 10/19/2021
The vulnerability identified as CVE-2011-1285 represents a critical flaw in Google Chrome's regular expression engine that stems from improper reentrancy handling within the browser's JavaScript execution environment. This issue affects Chrome versions prior to 10.0.648.127 and demonstrates a fundamental weakness in how the browser processes regular expression patterns, particularly when these patterns are invoked recursively or in nested contexts. The flaw manifests in the underlying V8 JavaScript engine's implementation of regular expression matching, where the reentrancy protection mechanisms fail to properly handle concurrent or nested regular expression operations.
The technical implementation of this vulnerability involves the browser's regular expression engine not properly managing the execution context when regular expression operations are reentered during pattern matching. This reentrancy issue occurs when a regular expression pattern contains constructs that trigger recursive evaluation or when multiple regular expression operations are processed simultaneously. The improper handling of these scenarios leads to memory corruption within the JavaScript engine's memory management system, creating a condition where the browser's memory layout becomes inconsistent. This memory corruption can result in unpredictable behavior including crashes, data corruption, or potentially more severe consequences if the memory corruption affects critical system components.
From an operational perspective, this vulnerability presents significant risk to users of affected Chrome versions as remote attackers can exploit it through web content without requiring user interaction. The attack vector typically involves visiting a malicious website that contains specially crafted regular expression patterns designed to trigger the reentrancy condition. The impact extends beyond simple denial of service, as the memory corruption could potentially be leveraged for more sophisticated attacks depending on the specific memory layout and execution context. This vulnerability aligns with CWE-691, which specifically addresses inadequate protection against reentrancy, and demonstrates how improper control flow management can lead to memory safety issues in interpreted languages.
The exploitation of this vulnerability requires an attacker to craft JavaScript code containing regular expression patterns that can trigger the reentrancy condition within Chrome's V8 engine. Attackers may use techniques such as nested quantifiers, backreferences, or complex pattern combinations that force the engine into recursive evaluation states. The vulnerability's impact can be categorized under the ATT&CK technique T1059.007 for JavaScript execution and T1499.004 for network denial of service. Organizations and users are advised to immediately update to Chrome version 10.0.648.127 or later, which includes patches addressing the reentrancy handling in the regular expression engine. Additional mitigations include implementing web application firewalls that can detect and block suspicious regular expression patterns, disabling JavaScript in untrusted environments, and maintaining comprehensive monitoring for unusual browser behavior or memory usage patterns that might indicate exploitation attempts.