CVE-2021-30577 in Chrome
Summary
by MITRE • 08/04/2021
Insufficient policy enforcement in Installer in Google Chrome prior to 92.0.4515.107 allowed a remote attacker to perform local privilege escalation via a crafted file.
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Analysis
by VulDB Data Team • 08/07/2021
The vulnerability identified as CVE-2021-30577 represents a critical security flaw in Google Chrome's installer component that existed prior to version 92.0.4515.107. This issue stems from insufficient policy enforcement mechanisms within the installer system, creating a pathway for remote attackers to execute local privilege escalation attacks. The vulnerability specifically targets the installer's ability to validate and enforce security policies during the installation process, allowing malicious actors to manipulate the installation flow and gain elevated system privileges. The flaw demonstrates a fundamental weakness in the security architecture of Chrome's installation mechanism, where proper access controls and validation checks were not adequately implemented to prevent unauthorized privilege elevation.
Technical exploitation of this vulnerability occurs when a remote attacker crafts a malicious file that the installer processes without proper validation. The installer component fails to enforce appropriate security policies that would normally prevent execution of untrusted code or modification of system resources during installation. This weakness enables attackers to manipulate the installation process in ways that would normally be blocked by proper policy enforcement. The vulnerability operates at the intersection of software installation security and privilege management, where the installer's failure to validate file integrity and execution permissions creates an attack surface that can be leveraged for privilege escalation. The flaw essentially allows an attacker to bypass normal security boundaries that should prevent a remote user from gaining local administrative privileges through the installation process.
The operational impact of CVE-2021-30577 extends beyond simple privilege escalation, as it represents a significant compromise of system integrity and user security. Successful exploitation enables attackers to gain elevated privileges that would typically require local system access or administrative credentials, effectively allowing remote code execution with system-level privileges. This vulnerability particularly affects systems where Chrome is frequently updated or where automatic installation features are enabled, as these scenarios provide more opportunities for exploitation. The remote nature of the attack means that users need not have physical access to the target system, making the vulnerability particularly dangerous in enterprise environments where multiple users may be running vulnerable versions of Chrome. The vulnerability also impacts the overall trust model of the browser installation process, potentially allowing attackers to install malicious software or modify system configurations without proper authorization.
Mitigation strategies for CVE-2021-30577 primarily focus on immediate patching of affected Chrome versions, with users upgrading to version 92.0.4515.107 or later. Organizations should implement strict update policies and ensure that all Chrome installations are kept current with security patches. Network administrators should monitor for exploitation attempts and consider implementing additional security controls such as application whitelisting to prevent execution of unauthorized installer components. The vulnerability aligns with CWE-284, which describes improper access control in software systems, and represents a clear violation of the principle of least privilege. From an ATT&CK framework perspective, this vulnerability maps to privilege escalation techniques where adversaries leverage software vulnerabilities to gain elevated system access, specifically targeting the installer component as an attack vector. Additional defensive measures include implementing secure installation practices, monitoring for unusual installation activity, and maintaining comprehensive system integrity checks to detect potential exploitation attempts.