CVE-2016-1665 in Chrome
Summary
by MITRE
The JSGenericLowering class in compiler/js-generic-lowering.cc in Google V8, as used in Google Chrome before 50.0.2661.94, mishandles comparison operators, which allows remote attackers to obtain sensitive information via crafted JavaScript code.
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Analysis
by VulDB Data Team • 08/19/2022
The vulnerability identified as CVE-2016-1665 resides within the JSGenericLowering class of Google V8 JavaScript engine, which serves as the core runtime for Google Chrome browser and Node.js environments. This flaw manifests in the compiler's handling of comparison operators during the JavaScript code compilation process, specifically in the js-generic-lowering.cc source file. The issue represents a critical security weakness that enables remote attackers to exploit the JavaScript engine's internal representation of comparison operations, potentially leading to information disclosure vulnerabilities.
The technical nature of this vulnerability stems from improper handling of comparison operators within V8's intermediate representation lowering phase, where the compiler translates high-level JavaScript constructs into lower-level machine instructions. When JavaScript code containing specific comparison operations is processed through this flawed component, the compiler fails to properly account for certain edge cases in the operand handling, creating opportunities for attackers to craft malicious JavaScript code that can manipulate the compiler's internal state. This mismanagement occurs during the compilation phase rather than execution, making it particularly dangerous as it can be exploited before the code reaches runtime.
The operational impact of this vulnerability extends beyond simple information disclosure, as it provides attackers with a means to potentially extract sensitive data from the browser's memory or internal structures. Remote attackers can leverage this weakness by crafting JavaScript code that triggers specific patterns in comparison operations, allowing them to observe memory contents or internal state information that should remain confidential. The vulnerability affects Google Chrome versions prior to 50.0.2661.94, representing a significant portion of users who were exposed to this risk. This flaw can be exploited in various attack scenarios including cross-site scripting attacks, where attackers can use the information leakage to further compromise user sessions or system integrity.
The vulnerability aligns with CWE-200, which addresses "Information Exposure," and demonstrates characteristics consistent with the ATT&CK technique T1059.007 for "Command and Scripting Interpreter: JavaScript," as it exploits the JavaScript engine's compilation process to achieve information disclosure. Organizations and users affected by this vulnerability should prioritize immediate patching of their Chrome installations to mitigate the risk. The recommended mitigation strategy involves updating to Chrome version 50.0.2661.94 or later, which contains the necessary fixes to properly handle comparison operators within the JSGenericLowering class. Additionally, administrators should monitor for any potential exploitation attempts and implement proper input validation for JavaScript code execution, particularly in environments where untrusted code is executed. Security researchers and developers should also consider the implications of similar flaws in other JavaScript engine components and review their code for similar patterns in operator handling during compilation phases.