CVE-2022-21970: Microsoft Edge Privilege Escalation Flaw

CVE-2022-21970 Overview

CVE-2022-21970 is an Elevation of Privilege vulnerability affecting Microsoft Edge (Chromium-based). This vulnerability allows attackers to elevate their privileges on a system through the browser, potentially gaining unauthorized access to sensitive resources or executing actions with higher-level permissions than intended.

Critical Impact

Successful exploitation of this vulnerability could allow an attacker to gain elevated privileges on the affected system, potentially leading to complete compromise of confidentiality, integrity, and availability of the targeted environment.

Affected Products

• Microsoft Edge (Chromium-based)

Discovery Timeline

• 2022-01-11 - CVE-2022-21970 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-21970

Vulnerability Analysis

This Elevation of Privilege vulnerability in Microsoft Edge (Chromium-based) is classified under CWE-269 (Improper Privilege Management). The vulnerability requires local access and user interaction to exploit, meaning an attacker would need to convince a user to perform specific actions or access malicious content through the browser. Upon successful exploitation, the attacker could gain elevated privileges that allow unauthorized access to system resources and capabilities beyond the browser's intended security boundaries.

Root Cause

The root cause of CVE-2022-21970 is improper privilege management (CWE-269) within the Microsoft Edge browser. This class of vulnerability occurs when an application does not properly restrict the allocation or management of privileges, allowing attackers to bypass security controls and assume higher-level permissions. In the context of a browser, this could involve flaws in how the application handles process isolation, permission boundaries, or user context switching.

Attack Vector

The attack vector for this vulnerability is local, requiring the attacker to have some form of access to the target system. Successful exploitation requires user interaction—the victim must take some action, such as clicking a link, opening a malicious file, or visiting a compromised website through Microsoft Edge. Once triggered, the vulnerability enables privilege escalation without requiring prior authentication, though the scope remains unchanged (the attack does not extend beyond the original security boundary).

The exploitation mechanism involves leveraging the improper privilege management flaw to execute operations with elevated permissions. Technical details are available in the Microsoft Security Advisory.

Detection Methods for CVE-2022-21970

Indicators of Compromise

• Unexpected privilege escalation events associated with Microsoft Edge processes
• Unusual child process spawning from msedge.exe with elevated permissions
• Anomalous registry modifications or file system changes initiated by browser processes
• Windows Event Log entries indicating privilege escalation attempts

Detection Strategies

• Monitor for unusual process behavior from Microsoft Edge, particularly processes running with elevated privileges
• Implement endpoint detection rules to identify privilege escalation patterns associated with browser exploitation
• Deploy behavior-based detection for suspicious browser process activities that attempt to access protected system resources
• Review Windows Security Event logs for privilege escalation indicators (Event IDs 4672, 4673, 4674)

Monitoring Recommendations

• Enable detailed logging for Microsoft Edge and associated Chromium processes
• Configure SIEM alerts for privilege escalation patterns originating from browser applications
• Monitor endpoint telemetry for browser processes attempting to access sensitive system directories or registry keys
• Implement user behavior analytics to detect anomalous browser activity patterns

How to Mitigate CVE-2022-21970

Immediate Actions Required

• Update Microsoft Edge to the latest version immediately
• Enable automatic updates for Microsoft Edge to ensure timely security patches
• Review and restrict user permissions on sensitive systems where elevation of privilege poses significant risk
• Implement application control policies to limit browser capabilities on high-security endpoints

Patch Information

Microsoft has addressed this vulnerability through security updates for Microsoft Edge (Chromium-based). Organizations should apply the latest browser updates as soon as possible. Detailed patch information is available in the Microsoft CVE-2022-21970 Update Guide.

Workarounds

• Restrict local access to systems where Microsoft Edge is installed on sensitive endpoints
• Implement the principle of least privilege for user accounts to minimize the impact of privilege escalation
• Consider using browser isolation solutions to contain potential exploitation attempts
• Deploy endpoint protection solutions with behavior-based detection capabilities to identify exploitation attempts

# Verify Microsoft Edge version and check for updates
# Open Edge and navigate to edge://settings/help
# Or use PowerShell to check the installed version
Get-ItemProperty -Path "HKLM:\SOFTWARE\Microsoft\Edge" | Select-Object Version