CVE-2024-38047: Windows PowerShell Privilege Escalation

CVE-2024-38047 Overview

CVE-2024-38047 is a privilege escalation vulnerability affecting Windows PowerShell across multiple versions of Microsoft Windows operating systems. This vulnerability allows a local attacker with low-level privileges to elevate their access and gain high-level control over an affected system, potentially compromising confidentiality, integrity, and availability of critical data and system resources.

Critical Impact

Successful exploitation enables an authenticated local attacker to escalate privileges from a standard user to a higher privilege level, potentially gaining SYSTEM-level access and full control over the affected Windows system.

Affected Products

• Microsoft Windows 10 (versions 1607, 1809, 21H2, 22H2)
• Microsoft Windows 11 (versions 21H2, 22H2, 23H2)
• Microsoft Windows Server 2016
• Microsoft Windows Server 2019
• Microsoft Windows Server 2022
• Microsoft Windows Server 2022 23H2

Discovery Timeline

• 2024-07-09 - CVE-2024-38047 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2024-38047

Vulnerability Analysis

This elevation of privilege vulnerability exists in Windows PowerShell due to improper input validation (CWE-20). PowerShell is a task automation framework consisting of a command-line shell and associated scripting language built on the .NET framework. The vulnerability allows an authenticated attacker who has local access to the system to execute malicious operations that bypass normal security constraints.

The attack requires local access and low privileges to initiate, but successful exploitation yields high impact across all three security pillars—confidentiality, integrity, and availability. No user interaction is required for exploitation, making this vulnerability particularly concerning for enterprise environments where attackers may already have a foothold through compromised user accounts.

Root Cause

The underlying cause of CVE-2024-38047 is improper input validation (CWE-20) within the PowerShell component. When certain inputs are processed by PowerShell, the lack of proper validation allows an attacker to craft malicious inputs that manipulate the execution context, resulting in elevated privileges. This input validation flaw enables the bypass of intended security boundaries within the Windows operating system.

Attack Vector

The attack vector is local, meaning an attacker must have authenticated access to the target system to exploit this vulnerability. The attack complexity is low, requiring no specialized conditions or additional information gathering. A typical attack scenario involves:

1. An attacker gains initial access to a Windows system with standard user credentials
2. The attacker leverages the PowerShell vulnerability by providing crafted inputs
3. The improper input validation allows the attacker to escape the intended privilege boundary
4. The attacker achieves elevated privileges, potentially gaining SYSTEM-level access

No public proof-of-concept or exploit code has been identified for this vulnerability at this time.

Detection Methods for CVE-2024-38047

Indicators of Compromise

• Unusual PowerShell execution patterns from non-administrative accounts attempting privileged operations
• PowerShell processes spawning unexpected child processes with elevated privileges
• Anomalous Windows Event Log entries showing privilege escalation attempts (Event IDs 4672, 4673)
• Unexpected modifications to system files or registry keys originating from PowerShell processes

Detection Strategies

• Enable and monitor PowerShell Script Block Logging (Event ID 4104) to capture executed commands
• Configure Windows Defender ATP or SentinelOne to alert on suspicious PowerShell privilege escalation patterns
• Implement behavioral detection rules for PowerShell processes that spawn elevated child processes
• Deploy endpoint detection and response (EDR) solutions to monitor for anomalous privilege transitions

Monitoring Recommendations

• Enable PowerShell transcription and module logging across all Windows endpoints
• Configure SIEM correlation rules to detect privilege escalation patterns involving PowerShell
• Monitor for PowerShell executions from unexpected directories or with obfuscated command lines
• Implement Just Enough Administration (JEA) to restrict PowerShell capabilities for standard users

How to Mitigate CVE-2024-38047

Immediate Actions Required

• Apply the Microsoft security updates released in July 2024 Patch Tuesday immediately
• Prioritize patching domain controllers and servers with critical roles
• Conduct an inventory of all Windows systems to identify unpatched instances
• Implement network segmentation to limit lateral movement if exploitation occurs

Patch Information

Microsoft has released security updates to address CVE-2024-38047 as part of the July 2024 security updates. Detailed patch information and affected KB articles are available in the Microsoft Security Update Guide. Organizations should deploy these updates through their standard patch management processes, prioritizing internet-facing systems and critical infrastructure.

Workarounds

• Restrict PowerShell execution policies using Set-ExecutionPolicy to limit script execution
• Implement PowerShell Constrained Language Mode on high-value systems to restrict functionality
• Use AppLocker or Windows Defender Application Control (WDAC) to restrict PowerShell execution to authorized users
• Disable PowerShell v2 engine which may bypass modern security controls

# Disable PowerShell v2 Engine (recommended security hardening)
Disable-WindowsOptionalFeature -Online -FeatureName MicrosoftWindowsPowerShellV2Root

# Enable Constrained Language Mode via environment variable
[Environment]::SetEnvironmentVariable('__PSLockdownPolicy', '4', 'Machine')

# Verify PowerShell logging is enabled via Group Policy
# Computer Configuration > Administrative Templates > Windows Components > Windows PowerShell
# Enable "Turn on Script Block Logging"
# Enable "Turn on Module Logging"