CVE-2020-1571: Windows 10 Privilege Escalation Flaw

CVE-2020-1571 Overview

An elevation of privilege vulnerability exists in Windows Setup in the way it handles permissions. A locally authenticated attacker could exploit this flaw to run arbitrary code with elevated system privileges. After successfully exploiting the vulnerability, an attacker could then install programs; view, change, or delete data; or create new accounts with full user rights.

This vulnerability stems from improper permission handling within the Windows Setup component, classified as CWE-276 (Incorrect Default Permissions). The flaw allows attackers who already have local access to escalate their privileges to SYSTEM level, effectively gaining complete control over the affected Windows system.

Critical Impact

Local privilege escalation enabling complete system compromise with SYSTEM-level access, allowing attackers to install malicious programs, modify or delete critical data, and create new accounts with administrative privileges.

Affected Products

• Microsoft Windows 10 version 1803
• Microsoft Windows 10 version 1809
• Microsoft Windows 10 version 1903
• Microsoft Windows 10 version 1909
• Microsoft Windows 10 version 2004

Discovery Timeline

• 2020-08-17 - CVE-2020-1571 published to NVD
• 2026-02-23 - Last updated in NVD database

Technical Details for CVE-2020-1571

Vulnerability Analysis

The vulnerability resides in the Windows Setup component, which improperly handles permissions during system configuration operations. This incorrect default permissions flaw (CWE-276) creates a security gap that can be leveraged by locally authenticated users to bypass intended access controls.

When Windows Setup executes certain operations, it fails to properly validate and enforce permission boundaries. This allows a low-privileged local user to interact with the Setup component in ways that were not intended, ultimately leading to code execution in a privileged context.

The attack requires local access and a valid user account on the target system, but does not require any user interaction beyond the attacker's own actions. Once exploited, the attacker gains the highest level of system privileges, enabling unrestricted access to the compromised machine.

Root Cause

The root cause of CVE-2020-1571 is incorrect default permissions (CWE-276) in the Windows Setup component. The Setup process does not properly restrict access to certain resources or operations, allowing authenticated local users to escalate their privileges. This fundamental access control weakness enables attackers to bypass security boundaries that should prevent non-administrative users from executing code with elevated privileges.

Attack Vector

The attack vector for this vulnerability is local, requiring the attacker to have authenticated access to the target Windows 10 system. The exploitation path involves:

1. An attacker with low-level local access identifies the vulnerable Windows Setup component
2. The attacker leverages the improper permission handling to inject or execute arbitrary code
3. Due to the permission misconfiguration, this code executes with SYSTEM privileges
4. With elevated access, the attacker can perform any administrative action including installing backdoors, exfiltrating data, or establishing persistence

The vulnerability does not require user interaction and has low attack complexity once local access is obtained. No public exploit code has been identified for this vulnerability, and it is not listed in CISA's Known Exploited Vulnerabilities catalog.

Detection Methods for CVE-2020-1571

Indicators of Compromise

• Unexpected process execution originating from Windows Setup components with SYSTEM privileges
• Unusual child processes spawned by Setup-related executables
• New user accounts created without authorized administrative action
• Suspicious modifications to system files or registry keys following Setup component activity

Detection Strategies

• Monitor for unusual process creation events where the parent process is related to Windows Setup
• Implement Windows event log monitoring for privilege escalation attempts (Event ID 4672, 4673)
• Deploy endpoint detection solutions capable of identifying anomalous behavior patterns in system components
• Establish baseline behavior for Setup-related processes and alert on deviations

Monitoring Recommendations

• Enable detailed Windows Security event logging, particularly for process creation and privilege use
• Configure SentinelOne behavioral AI to detect privilege escalation attempts targeting Windows system components
• Monitor for unauthorized account creation events (Event ID 4720)
• Review system logs for any unexpected Windows Setup component execution outside of legitimate update scenarios

How to Mitigate CVE-2020-1571

Immediate Actions Required

• Apply the security update from Microsoft immediately to all affected Windows 10 systems
• Restrict local access to systems to only necessary personnel
• Audit existing user accounts for unauthorized privilege escalation
• Implement the principle of least privilege across all endpoints

Patch Information

Microsoft has released a security update that addresses the vulnerability by ensuring Windows Setup properly handles permissions. The official patch information is available through the Microsoft Security Advisory for CVE-2020-1571.

Organizations should deploy the appropriate security updates for their Windows 10 version:

• Windows 10 version 1803
• Windows 10 version 1809
• Windows 10 version 1903
• Windows 10 version 1909
• Windows 10 version 2004

Workarounds

• Limit local access to Windows 10 systems to only trusted and necessary users
• Implement application whitelisting to prevent unauthorized code execution
• Deploy endpoint protection solutions with behavioral detection capabilities such as SentinelOne
• Consider implementing network segmentation to limit the impact of any successful privilege escalation

# Review current security patch status
wmic qfe list brief /format:table

# Check Windows version for applicability
winver

# Review local user privileges
net localgroup administrators