CVE-2024-49046: Windows 10 1507 Privilege Escalation Flaw

CVE-2024-49046 Overview

CVE-2024-49046 is an elevation of privilege vulnerability in the Windows Win32 Kernel Subsystem that affects a wide range of Microsoft Windows operating systems. This vulnerability allows an authenticated local attacker to escalate privileges on the affected system by exploiting a Time-of-Check Time-of-Use (TOCTOU) race condition (CWE-367). Successful exploitation could grant the attacker elevated privileges, potentially allowing them to execute arbitrary code with SYSTEM-level permissions.

Critical Impact

An attacker who successfully exploits this vulnerability could gain elevated privileges on the target system, potentially achieving full system control and the ability to install programs, view or modify data, or create new accounts with complete user rights.

Affected Products

• Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2) - x86, x64, and ARM64 architectures
• Microsoft Windows 11 (versions 22H2, 23H2, 24H2) - x64 and ARM64 architectures
• Microsoft Windows Server 2008, 2008 R2, 2012, 2012 R2, 2016, 2019, 2022, 2022 23H2, and 2025

Discovery Timeline

• November 12, 2024 - CVE-2024-49046 published to NVD
• November 18, 2024 - Last updated in NVD database

Technical Details for CVE-2024-49046

Vulnerability Analysis

This vulnerability exists within the Windows Win32 Kernel Subsystem, a core component responsible for managing system calls and interfacing between user-mode applications and the Windows kernel. The flaw is classified as CWE-367, which indicates a Time-of-Check Time-of-Use (TOCTOU) race condition vulnerability.

A TOCTOU vulnerability occurs when a system performs a security check on a resource, but the state of that resource changes between the time of the check and the time of use. In the context of the Win32 Kernel Subsystem, this could allow an attacker to manipulate security-relevant data or conditions after validation but before the operation completes, bypassing security controls intended to prevent privilege escalation.

The vulnerability requires local access and low privileges to exploit, meaning an attacker must first obtain the ability to execute low-privileged code on the target system. However, no user interaction is required once the attacker has local access.

Root Cause

The root cause of CVE-2024-49046 is a Time-of-Check Time-of-Use (TOCTOU) race condition in the Windows Win32 Kernel Subsystem. This occurs when the subsystem validates certain conditions or permissions and then acts on them, but the window between validation and action allows an attacker to alter the state being validated. This type of race condition is particularly dangerous in kernel-level code, as it can lead to privilege escalation from user mode to kernel mode.

Attack Vector

The attack vector for CVE-2024-49046 is local, requiring the attacker to have authenticated access to the target system with low-level privileges. The exploitation process involves:

1. An attacker with low-privilege access identifies a vulnerable code path in the Win32 Kernel Subsystem
2. The attacker crafts a race condition exploit that manipulates the state of a security-relevant resource between the time the kernel checks permissions and when it uses that resource
3. By winning the race condition, the attacker bypasses security checks and gains elevated privileges
4. The attacker achieves SYSTEM-level access, enabling full control over the compromised system

This vulnerability does not require any user interaction to exploit once the attacker has local access. The exploitation complexity is low, making it an attractive target for attackers who have already gained initial access to a system through other means.

Detection Methods for CVE-2024-49046

Indicators of Compromise

• Unusual process creation events from low-privilege accounts attempting to access kernel resources
• Suspicious timing patterns in system calls related to the Win32 Kernel Subsystem
• Unexpected privilege elevation events in Windows Security Event logs
• Abnormal behavior from processes that typically run with limited privileges

Detection Strategies

• Monitor Windows Security Event logs for Event ID 4672 (Special privileges assigned to new logon) from unexpected sources
• Implement behavioral analysis to detect rapid, repeated system calls that may indicate race condition exploitation attempts
• Deploy endpoint detection solutions capable of identifying privilege escalation attempts in kernel subsystems
• Monitor for unusual process token manipulation or impersonation activities

Monitoring Recommendations

• Enable detailed audit logging for privilege use and process creation events
• Configure SentinelOne agents to monitor kernel-level operations and flag suspicious privilege escalation patterns
• Implement real-time alerting for attempts to exploit known Windows kernel vulnerabilities
• Regularly review system integrity and process execution patterns for anomalies

How to Mitigate CVE-2024-49046

Immediate Actions Required

• Apply the Microsoft security update released in November 2024 as soon as possible
• Prioritize patching on systems where users have local access, as this is a local privilege escalation vulnerability
• Implement the principle of least privilege to minimize the impact of potential exploitation
• Review and restrict local user account permissions where possible

Patch Information

Microsoft has released security updates to address this vulnerability as part of their November 2024 Patch Tuesday release. Detailed patch information and download links are available through the Microsoft Security Response Center advisory. Organizations should deploy these patches using their standard update mechanisms, such as Windows Update, WSUS, or Microsoft Configuration Manager.

The patches address the TOCTOU race condition by implementing proper synchronization mechanisms in the affected Win32 Kernel Subsystem code paths.

Workarounds

• Restrict local access to systems to only essential personnel until patches can be applied
• Implement application whitelisting to prevent unauthorized code execution
• Use Windows Defender Credential Guard where available to help protect against credential theft that could enable local access
• Deploy SentinelOne's behavioral AI engine to detect and block exploitation attempts in real-time

# Verify Windows Update status and install latest security updates
# Run in elevated PowerShell
Get-WindowsUpdate -Install -AcceptAll -AutoReboot

# Check if the November 2024 cumulative update is installed
Get-HotFix | Where-Object {$_.InstalledOn -ge "2024-11-01"} | Format-Table -AutoSize

# Enable advanced audit policy for privilege use monitoring
auditpol /set /subcategory:"Sensitive Privilege Use" /success:enable /failure:enable