CVE-2018-6074 in Chrome
Summary
by MITRE
Failure to apply Mark-of-the-Web in Downloads in Google Chrome prior to 65.0.3325.146 allowed a remote attacker to bypass OS level controls via a crafted HTML page.
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Analysis
by VulDB Data Team • 06/06/2023
The vulnerability identified as CVE-2018-6074 represents a critical security flaw in Google Chrome's handling of downloaded files and their associated security markings. This issue specifically affects Chrome versions prior to 65.0.3325.146 and stems from the browser's failure to properly implement the Mark-of-the-Web (MOTW) mechanism when processing downloads. The MOTW is a Windows security feature designed to mark files downloaded from the internet with security attributes that inform the operating system about the file's origin and trust level. When this mechanism fails to apply correctly, it creates a pathway for attackers to circumvent the operating system's built-in security controls that would normally restrict execution of potentially malicious files downloaded from untrusted sources.
The technical implementation of this vulnerability exploits the gap between Chrome's download handling and the underlying operating system's security policies. When Chrome downloads files, it should apply the MOTW to indicate that the file originated from the internet and should be treated with appropriate security restrictions. However, due to this flaw, the browser failed to properly set these security markings, allowing downloaded files to bypass Windows' Protected View and other security measures that would normally prevent execution of potentially harmful content. Attackers could craft malicious HTML pages that, when downloaded by victims, would appear as trusted local files rather than internet-originated content, thereby evading the OS-level protections designed to prevent automatic execution of downloaded files.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it fundamentally undermines the security model of the operating system by allowing attackers to bypass multiple layers of protection. This flaw enables remote code execution scenarios where attackers can deliver malicious payloads that would normally be blocked by the OS, effectively neutralizing the security boundaries that separate trusted local content from potentially malicious internet downloads. The vulnerability is particularly dangerous because it operates at the intersection of browser security and operating system security controls, creating a scenario where a single browser flaw can compromise the entire system's defense-in-depth strategy. Security researchers have classified this issue as a significant risk to enterprise environments where users may download files from untrusted sources, as it essentially allows attackers to manipulate how the operating system treats downloaded content.
Mitigation strategies for CVE-2018-6074 primarily focus on immediate browser updates and system hardening measures. Organizations should prioritize updating all affected Chrome installations to version 65.0.3325.146 or later, which includes the necessary patches to properly implement the Mark-of-the-Web mechanism. Additionally, system administrators should implement enhanced monitoring of download activities and consider implementing additional security controls such as Application Control policies or endpoint protection solutions that can detect and block suspicious file execution patterns. The vulnerability demonstrates the importance of maintaining up-to-date software and highlights the critical nature of browser security features that interface with operating system security mechanisms. From a compliance perspective, this vulnerability aligns with various security frameworks including NIST SP 800-53 controls related to system and information integrity, as it represents a failure to maintain proper security boundaries between trusted and untrusted content sources. The issue also maps to ATT&CK technique T1059.001 for command and script interpreter, as it enables attackers to execute malicious code through compromised download mechanisms that bypass normal security controls.