CVE-2018-6131 in Chrome
Summary
by MITRE
Object lifecycle issue in WebAssembly in Google Chrome prior to 67.0.3396.62 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 07/18/2024
The vulnerability identified as CVE-2018-6131 represents a critical object lifecycle management flaw within Google Chrome's WebAssembly implementation that existed prior to version 67.0.3396.62. This issue manifests as a heap corruption vulnerability that can be remotely exploited through maliciously crafted HTML pages, demonstrating the complex security challenges inherent in modern web browser implementations where low-level runtime environments interact with high-level web applications. The vulnerability specifically targets the way Chrome handles object references and memory management during WebAssembly execution, creating potential attack vectors that could be leveraged by remote adversaries to compromise system integrity.
The technical root cause of this vulnerability stems from improper handling of object references within Chrome's WebAssembly runtime environment, where objects are not correctly managed during their lifecycle phases. This object lifecycle issue creates conditions where memory allocated for WebAssembly objects can be accessed or modified inappropriately, leading to heap corruption that may allow attackers to execute arbitrary code. The flaw occurs during the interaction between JavaScript and WebAssembly components, where reference counting or garbage collection mechanisms fail to properly track object dependencies, particularly when objects are shared between different execution contexts or when objects are destroyed while still referenced elsewhere in the system. This type of vulnerability aligns with CWE-415 which describes improper handling of object lifecycle management, and specifically relates to memory safety issues in runtime environments.
From an operational impact perspective, this vulnerability presents a significant risk to web users as it requires no local privileges to exploit and can be triggered through simple web page navigation. Attackers can craft malicious HTML pages that, when loaded in affected Chrome versions, initiate the vulnerable code path and potentially achieve remote code execution on the target system. The exploitation process typically involves creating specific WebAssembly modules that trigger the object lifecycle race condition, followed by heap spraying or memory manipulation techniques to achieve reliable code execution. This vulnerability demonstrates the attack surface expansion that occurs when complex runtime environments like WebAssembly are integrated into web browsers, as these environments often operate with elevated privileges and can directly access system resources.
The mitigation strategies for CVE-2018-6131 primarily focus on updating Chrome to version 67.0.3396.62 or later, which includes patches that correct the object lifecycle management issues in the WebAssembly implementation. Organizations should also consider implementing additional security measures such as content security policies that restrict WebAssembly execution, browser hardening configurations, and network-level protections that can detect and block malicious WebAssembly content. Security teams should monitor for exploitation attempts through network traffic analysis and web application firewalls that can identify suspicious WebAssembly module loading patterns. This vulnerability also highlights the importance of continuous security testing for modern web browsers and runtime environments, as the complexity of these systems creates numerous potential attack surfaces that may not be immediately apparent during initial development and testing phases. The ATT&CK framework categorizes this vulnerability under techniques related to code injection and privilege escalation, emphasizing the need for comprehensive browser security controls that address both client-side and server-side attack vectors.