CVE-2018-16088 in Chrome
Summary
by MITRE
A missing check for JS-simulated input events in Blink in Google Chrome prior to 69.0.3497.81 allowed a remote attacker to download arbitrary files with no user input via a crafted HTML page.
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Analysis
by VulDB Data Team • 08/02/2024
This vulnerability resides within the Blink rendering engine that powers Google Chrome and several other web browsers. The flaw represents a critical security gap in how the browser handles simulated input events, specifically those generated through JavaScript. The vulnerability stems from insufficient validation mechanisms that fail to properly distinguish between genuine user interactions and programmatically generated events. Attackers could exploit this weakness by crafting malicious HTML pages that simulate user actions to trigger file downloads without any actual user consent or interaction.
The technical implementation of this vulnerability allows remote attackers to bypass normal browser security controls that typically require explicit user engagement for file operations. When a malicious webpage loads, it can programmatically generate input events that appear to originate from legitimate user actions, thereby tricking the browser into executing file download operations automatically. This occurs because the browser's event handling system does not adequately verify the authenticity of input events before proceeding with potentially dangerous operations such as file downloads or system access. The vulnerability specifically affects Chrome versions prior to 69.0.3497.81, indicating that the fix involved implementing additional validation checks for JavaScript-generated events.
The operational impact of this vulnerability is severe as it enables automated malicious file downloads without user awareness or consent. Attackers could potentially deploy this exploit to deliver malware, steal sensitive data, or perform other malicious activities through seemingly benign web pages. The vulnerability is particularly dangerous because it operates entirely within the browser environment and does not require any special privileges or user interaction beyond visiting a malicious website. This makes it an attractive target for phishing campaigns, drive-by download attacks, and other forms of automated exploitation where attackers seek to maximize impact with minimal user engagement requirements.
The underlying cause of this vulnerability aligns with common software security weaknesses categorized under CWE-691, which deals with insufficient control flow protection and improper event handling. From an adversarial perspective, this flaw maps directly to techniques described in the ATT&CK framework under T1193 - Spearphishing Attachment, where attackers leverage browser-based exploits to deliver malicious payloads. The vulnerability demonstrates how inadequate input validation can lead to privilege escalation within the browser context, potentially allowing attackers to execute arbitrary code or access sensitive system resources. Security researchers identified that the fix required implementing stricter validation of event sources to ensure that only legitimate user-generated events could trigger sensitive operations like file downloads. Organizations should prioritize updating to Chrome version 69.0.3497.81 or later to remediate this vulnerability, while also implementing additional browser security measures such as content security policies and sandboxing techniques to further reduce the attack surface.