CVE-2019-5780 in Chrome
Summary
by MITRE
Insufficient restrictions on what can be done with Apple Events in Google Chrome on macOS prior to 72.0.3626.81 allowed a local attacker to execute JavaScript via Apple Events.
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Analysis
by VulDB Data Team • 06/27/2024
The vulnerability CVE-2019-5780 represents a critical security flaw in Google Chrome's handling of Apple Events on macOS systems. This issue stems from insufficient validation and restriction mechanisms that govern how Apple Events are processed within the browser environment. Apple Events are a macOS technology that allows applications to communicate with each other and automate tasks through event-based scripting. The vulnerability specifically affects Chrome versions prior to 72.0.3626.81, creating a significant attack surface that could be exploited by local adversaries.
The technical flaw manifests in Chrome's improper handling of Apple Events that contain JavaScript code. When a malicious Apple Event is received, the browser fails to adequately sanitize or restrict the execution context of the embedded JavaScript, allowing arbitrary code to be executed within the browser's JavaScript engine. This represents a classic case of insufficient input validation and privilege escalation, where a local attacker can leverage Apple Events to bypass normal security boundaries. The vulnerability is particularly concerning because it operates at the system level, utilizing macOS native event handling mechanisms that are typically considered trusted and secure.
From an operational impact perspective, this vulnerability creates a serious risk for macOS users running affected Chrome versions. A local attacker with access to the system can craft malicious Apple Events that, when processed by Chrome, execute arbitrary JavaScript code with the privileges of the browser process. This could potentially lead to full system compromise, as the executed JavaScript could leverage additional browser vulnerabilities or access sensitive user data. The attack vector is particularly stealthy since Apple Events are legitimate macOS features that are often used for legitimate automation purposes, making such attacks harder to detect through traditional security monitoring.
The vulnerability aligns with CWE-20, "Improper Input Validation," and CWE-78, "Improper Neutralization of Special Elements used in OS Command Injection," as it involves inadequate validation of external input and improper handling of system-level events. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 "Command and Scripting Interpreter: JavaScript' and T1068 'Exploitation for Privilege Escalation' as it enables JavaScript execution and potential privilege escalation through Apple Event manipulation. The attack chain typically involves crafting a malicious Apple Event containing JavaScript code, which is then processed by Chrome, leading to arbitrary code execution. Organizations should prioritize immediate patching of affected Chrome versions and implement monitoring for unusual Apple Event activity on systems where Chrome is installed. Additionally, security teams should consider implementing application whitelisting policies to restrict which applications can send Apple Events to the browser process, providing an additional layer of defense against such attacks.