CVE-2020-6419 in Chrome
Summary
by MITRE
Out of bounds write in V8 in Google Chrome prior to 81.0.4044.92 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/04/2020
The vulnerability identified as CVE-2020-6419 represents a critical out-of-bounds write flaw within the V8 JavaScript engine that powers Google Chrome and other Chromium-based browsers. This vulnerability exists in versions prior to 81.0.4044.92 and allows remote attackers to potentially exploit heap corruption through carefully crafted HTML pages. The issue stems from insufficient bounds checking in V8's memory management operations, specifically when handling certain JavaScript objects and arrays during execution. The flaw manifests when the JavaScript engine attempts to write data beyond the allocated memory boundaries of an object, creating a condition where arbitrary memory locations can be overwritten. This type of vulnerability is particularly dangerous because it can lead to complete system compromise when exploited effectively.
The technical implementation of this vulnerability involves the V8 engine's handling of array operations and memory allocation patterns. When processing malicious JavaScript code that manipulates arrays or objects with specific memory layouts, the engine fails to properly validate array indices against allocated memory bounds. This allows an attacker to craft HTML content that, when rendered by Chrome, triggers memory corruption by writing data to locations outside the intended array or object boundaries. The vulnerability falls under the CWE-787 category of out-of-bounds write conditions, which are classified as high severity due to their potential for arbitrary code execution. Attackers can leverage this flaw to overwrite critical memory structures including function pointers, return addresses, or other control data that govern program execution flow.
The operational impact of CVE-2020-6419 extends beyond simple memory corruption, as it provides a pathway for remote code execution in the context of the victim's browser. When successfully exploited, an attacker can gain control over the victim's browser process and potentially escalate privileges to compromise the entire system. The attack surface is broad since the vulnerability can be triggered through standard web browsing activities, making it particularly dangerous for end users who may unknowingly visit compromised websites. This vulnerability aligns with ATT&CK technique T1059.007 for JavaScript and T1203 for Exploitation for Client Execution, as it exploits the browser's JavaScript engine to execute malicious code. The remote nature of the exploit means that users need not download any files or perform any special actions beyond visiting a malicious website, making it an ideal candidate for drive-by attacks in phishing campaigns or compromised websites.
Mitigation strategies for CVE-2020-6419 primarily focus on immediate remediation through software updates and browser patching. Organizations should prioritize updating all Chrome installations to version 81.0.4044.92 or later, where the vulnerability has been addressed through enhanced bounds checking and memory validation mechanisms. Additional defensive measures include implementing web application firewalls to filter suspicious JavaScript content, enabling content security policies to restrict script execution, and deploying sandboxing technologies to limit the impact of potential exploitation. Security teams should also monitor network traffic for indicators of exploitation attempts and maintain updated threat intelligence feeds to identify compromised websites. The vulnerability demonstrates the importance of regular security updates and the critical nature of keeping browser engines current, as V8's memory management improvements in later versions include enhanced protections against similar out-of-bounds write conditions. Organizations should also consider implementing browser hardening configurations that disable unnecessary JavaScript features and restrict memory allocation patterns that could facilitate exploitation of such vulnerabilities.