CVE-2013-6640 in Chrome
Summary
by MITRE
The DehoistArrayIndex function in hydrogen-dehoist.cc (aka hydrogen.cc) in Google V8 before 3.22.24.7, as used in Google Chrome before 31.0.1650.63, allows remote attackers to cause a denial of service (out-of-bounds read) via JavaScript code that sets a variable to the value of an array element with a crafted index.
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Analysis
by VulDB Data Team • 06/02/2021
The vulnerability identified as CVE-2013-6640 represents a critical out-of-bounds read flaw within Google V8's JavaScript engine, specifically affecting the DehoistArrayIndex function in hydrogen-dehoist.cc. This issue manifests in Google Chrome versions prior to 31.0.1650.63 and V8 versions before 3.22.24.7, creating a significant security risk that can be exploited remotely by malicious actors. The vulnerability stems from inadequate bounds checking during array index processing, allowing attackers to manipulate JavaScript code execution through crafted array access patterns.
The technical flaw occurs when the DehoistArrayIndex function fails to properly validate array indices before accessing array elements, resulting in an out-of-bounds memory read condition. This particular function operates within V8's hydrogen optimization phase, which is responsible for intermediate code generation and optimization. When JavaScript code attempts to access an array element with a maliciously crafted index, the function does not adequately verify that the index falls within the valid bounds of the array, potentially causing the engine to read memory locations outside the intended array boundaries. This flaw falls under CWE-129, which specifically addresses insufficient validation of the length of input data, and more broadly relates to CWE-787, concerning out-of-bounds write operations.
The operational impact of this vulnerability extends beyond simple denial of service, as it can potentially lead to information disclosure or even arbitrary code execution in certain circumstances. Remote attackers can exploit this vulnerability by crafting JavaScript code that sets a variable to the value of an array element with a specially crafted index, which triggers the out-of-bounds read condition. This attack vector allows adversaries to potentially access sensitive memory regions, extract information from the process memory, or destabilize the browser's execution environment. The vulnerability demonstrates characteristics consistent with the attack pattern described in the MITRE ATT&CK framework under T1059.007 for JavaScript and T1499.004 for network denial of service, where attackers leverage browser engine vulnerabilities to compromise system availability and confidentiality.
Mitigation strategies for CVE-2013-6640 primarily focus on immediate patching of affected software versions, with Google releasing updates to both Chrome and V8 that implement proper bounds checking in the DehoistArrayIndex function. Organizations should prioritize updating to Chrome version 31.0.1650.63 or later and V8 version 3.22.24.7 or later, which contain the necessary fixes to prevent the out-of-bounds read condition. Additionally, implementing content security policies and sandboxing measures can provide defense-in-depth protection against exploitation attempts. The vulnerability highlights the importance of robust input validation and memory safety practices in JavaScript engine implementations, particularly during optimization phases where code transformations occur. Security teams should also monitor for similar patterns in other JavaScript engines and ensure comprehensive testing of array access operations in their environments.