CVE-2018-6149 in Chrome
Summary
by MITRE
Type confusion in JavaScript in Google Chrome prior to 67.0.3396.87 allowed a remote attacker to perform an out of bounds memory write via a crafted HTML page.
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Analysis
by VulDB Data Team • 02/19/2020
The vulnerability identified as CVE-2018-6149 represents a critical type confusion flaw within Google Chrome's JavaScript engine that existed prior to version 67.0.3396.87. This issue stems from improper handling of object types during JavaScript execution, creating conditions where the browser's memory management system could be manipulated to execute unauthorized memory operations. The vulnerability specifically affects the V8 JavaScript engine used by Chrome, which is responsible for interpreting and executing JavaScript code in web pages. Type confusion vulnerabilities occur when a program incorrectly handles data types, leading to situations where memory allocated for one type of data structure is accessed as another type, potentially resulting in memory corruption.
The technical exploitation of this vulnerability requires a remote attacker to craft a malicious HTML page containing specifically designed JavaScript code that triggers the type confusion within the V8 engine. When Chrome processes this crafted page, the JavaScript engine fails to properly validate type consistency during object operations, allowing an attacker to manipulate memory pointers and execute arbitrary code. The flaw manifests as an out-of-bounds memory write condition, where the attacker can write data beyond the allocated memory boundaries of legitimate objects. This type of memory corruption can be leveraged to overwrite critical memory locations, potentially leading to complete system compromise. The vulnerability's classification aligns with CWE-476 which describes null pointer dereference conditions and CWE-121 which addresses stack-based buffer overflow conditions, though the specific manifestation involves type confusion rather than traditional buffer overflows.
The operational impact of CVE-2018-6149 extends beyond simple remote code execution, as it provides attackers with a sophisticated means of bypassing modern security mitigations such as address space layout randomization and data execution prevention. Successful exploitation can enable attackers to gain full control over affected systems, potentially leading to data theft, system compromise, or use as a foothold for further attacks within a network environment. The vulnerability's remote nature makes it particularly dangerous as it requires no user interaction beyond visiting a malicious website, making it an attractive target for automated attacks and exploit kits. Organizations using older versions of Chrome were exposed to significant risk, as the vulnerability could be exploited through standard web browsing activities without any user awareness or explicit action required from the victim.
Mitigation strategies for CVE-2018-6149 primarily focus on immediate remediation through software updates, with Google releasing Chrome version 67.0.3396.87 to address the vulnerability. System administrators should prioritize patching affected systems and implementing automated update mechanisms to prevent exploitation. Additional defensive measures include deploying web application firewalls, implementing strict content security policies, and utilizing sandboxing technologies that limit the impact of potential exploitation. The vulnerability demonstrates the importance of regular security updates and proper memory management practices in browser engines, aligning with ATT&CK technique T1059.007 for JavaScript-based attacks and T1070.004 for obfuscated files and information. Organizations should also consider implementing monitoring solutions that can detect anomalous JavaScript behavior patterns indicative of type confusion exploitation attempts, as well as maintaining comprehensive incident response procedures to address potential compromise scenarios.