CVE-2018-18345 in Chrome
Summary
by MITRE
Incorrect handling of blob URLS in Site Isolation in Google Chrome prior to 71.0.3578.80 allowed a remote attacker who had compromised the renderer process to bypass site isolation protections via a crafted HTML page.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/18/2023
The vulnerability identified as CVE-2018-18345 represents a critical flaw in Google Chrome's site isolation mechanism that was present in versions prior to 71.0.3578.80. This issue specifically targets the improper handling of blob URLs within the browser's security architecture, creating a pathway for remote attackers to circumvent fundamental isolation protections that separate different websites and their associated processes. The vulnerability falls under the category of process isolation bypass, where malicious actors can exploit weaknesses in the renderer process to gain unauthorized access to resources that should remain segregated between different origins.
The technical implementation of this vulnerability stems from how Chrome's site isolation feature manages blob URLs, which are special URLs that reference binary data stored in memory rather than traditional file system locations. When a renderer process is compromised, an attacker can craft a malicious HTML page that leverages the flawed blob URL handling to access memory segments or resources that should be isolated from the compromised process. This flaw essentially allows for a privilege escalation within the browser's security model, where the boundary protections that separate different websites become ineffective. The vulnerability is particularly dangerous because it operates at the intersection of browser security architecture and memory management, exploiting the trust relationship between different process compartments.
The operational impact of this vulnerability extends beyond simple information disclosure, as it enables attackers to potentially access sensitive data from other origins, execute arbitrary code in different browsing contexts, or perform cross-site scripting attacks that would normally be prevented by site isolation. Attackers could leverage this vulnerability to access cookies, local storage, or other origin-specific resources that should remain protected. The implications are significant for users who browse multiple sites simultaneously, as the compromise of one renderer process could lead to unauthorized access to data from other websites that were previously isolated. This vulnerability also demonstrates the complexity of modern browser security models and how subtle implementation flaws can create severe security implications.
Organizations and users should prioritize updating to Chrome version 71.0.3578.80 or later to address this vulnerability, as the fix involves correcting the blob URL handling logic within the site isolation framework. Security teams should also consider implementing additional monitoring for unusual renderer process behavior and ensure that browser updates are deployed promptly across all systems. The vulnerability aligns with CWE-276, which addresses improper privileges, and can be categorized under ATT&CK technique T1059 for execution through web-based attacks. Additionally, this issue highlights the importance of proper input validation and the need for comprehensive testing of security mechanisms that rely on process isolation and memory management to prevent unauthorized access patterns.