CVE-2018-18342 in Chrome
Summary
by MITRE
Execution of user supplied Javascript during object deserialization can update object length leading to an out of bounds write in V8 in Google Chrome prior to 71.0.3578.80 allowed a remote attacker to execute arbitrary code inside a sandbox via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/18/2023
This vulnerability represents a critical sandbox escape flaw in Google Chrome's V8 JavaScript engine that existed prior to version 71.0.3578.80. The issue stems from improper handling of object length updates during the deserialization process of JavaScript objects, creating a pathway for remote code execution within the browser's sandboxed environment. The vulnerability specifically targets the interaction between JavaScript object manipulation and the underlying V8 engine's memory management systems, where user-supplied JavaScript code can manipulate object properties in ways that bypass normal security boundaries.
The technical flaw manifests when malicious JavaScript code is executed during object deserialization, allowing an attacker to manipulate the length property of objects in a manner that triggers an out-of-bounds write condition. This occurs because the V8 engine fails to properly validate or constrain length updates during deserialization, enabling attackers to write data beyond the allocated memory boundaries of JavaScript objects. The vulnerability is categorized under CWE-121 as a stack-based buffer overflow, though it specifically exploits heap memory management issues within the JavaScript engine's object model implementation. The attack vector requires a crafted HTML page that can be delivered through web-based exploitation, making it particularly dangerous for remote code execution scenarios.
The operational impact of this vulnerability is severe as it allows remote attackers to execute arbitrary code within Chrome's sandboxed environment, effectively bypassing the security model that isolates web content from the underlying operating system. This sandbox escape capability enables attackers to perform actions such as reading arbitrary files, executing system commands, or accessing sensitive user data without user consent. The vulnerability's exploitation potential is further amplified by its ability to work through standard web browsing channels, making it accessible to attackers without requiring special privileges or local access. According to ATT&CK framework, this represents a technique for privilege escalation and code injection within the browser context.
Mitigation strategies for this vulnerability primarily involve upgrading to Google Chrome version 71.0.3578.80 or later, which includes patches that properly validate object length updates during deserialization. Organizations should implement comprehensive patch management procedures to ensure all browser installations are updated promptly. Additional defensive measures include enabling Chrome's sandboxing features, configuring content security policies, and implementing web application firewalls to detect and block malicious payloads. The fix addresses the root cause by strengthening input validation and memory boundary checks during JavaScript object deserialization, preventing the manipulation of object lengths that could lead to memory corruption. Security teams should also monitor for exploitation attempts through network traffic analysis and browser-based security tools to detect potential attempts to leverage this vulnerability in the wild.