CVE-2018-6140 in Chrome
Summary
by MITRE
Allowing the chrome.debugger API to attach to Web UI pages in DevTools in Google Chrome prior to 67.0.3396.62 allowed an attacker who convinced a user to install a malicious extension to execute arbitrary code via a crafted Chrome Extension.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/23/2023
The vulnerability described in CVE-2018-6140 represents a critical security flaw in Google Chrome's implementation of the chrome.debugger API within the DevTools environment. This issue affected Chrome versions prior to 67.0.3396.62 and fundamentally compromised the browser's security model by allowing unauthorized attachment to Web UI pages through the debugger interface. The vulnerability stems from insufficient access controls that permitted malicious extensions to exploit the debugger functionality to gain elevated privileges and execute arbitrary code within the browser context.
The technical flaw manifests through the chrome.debugger API's improper restriction of access to DevTools Web UI pages. When a malicious extension successfully convinced a user to install it, the extension could leverage the debugger capabilities to attach to sensitive browser interfaces. This attachment enabled the extension to manipulate the debugging process and ultimately execute arbitrary code with the privileges of the Chrome process. The vulnerability essentially created a backdoor through which attackers could bypass normal security boundaries that should have prevented such access to core browser components.
The operational impact of this vulnerability extends far beyond simple privilege escalation. Attackers could leverage this flaw to perform sophisticated attacks including but not limited to memory corruption exploitation, process injection, and code execution within the browser sandbox. The ability to attach to DevTools Web UI pages provided attackers with a powerful vector for bypassing Chrome's security mechanisms, potentially allowing them to access sensitive user data, manipulate browser functionality, or even escalate to system-level privileges. This vulnerability directly impacts the principle of least privilege and undermines the security architecture designed to isolate browser components.
The vulnerability aligns with CWE-284, which addresses improper access control, and represents a clear violation of the security principle that privileged operations should require proper authorization. From an ATT&CK framework perspective, this vulnerability maps to T1059.001 for command and scripting interpreter and T1068 for exploit for privilege escalation. The attack chain typically begins with social engineering to convince users to install malicious extensions, followed by exploitation of the debugger API to gain code execution capabilities. Organizations should prioritize immediate patching of affected Chrome versions and implement strict extension review processes to prevent installation of potentially malicious software. Additionally, browser security configurations should be reviewed to ensure proper sandboxing and access control mechanisms remain intact.