CVE-2022-24548: Microsoft Defender DoS Vulnerability

CVE-2022-24548 Overview

CVE-2022-24548 is a Denial of Service vulnerability affecting the Microsoft Malware Protection Engine, which is a core component of Microsoft Defender. This vulnerability allows an attacker to disrupt the normal functioning of the security software, potentially leaving systems unprotected during an attack window.

Critical Impact

Successful exploitation could disable Microsoft Defender's malware protection capabilities, leaving the system vulnerable to other attacks while the security software is in a degraded state.

Affected Products

• Microsoft Malware Protection Engine
• Microsoft Defender (all platforms utilizing the affected engine)
• Windows Security components dependent on the Malware Protection Engine

Discovery Timeline

• 2022-04-15 - CVE-2022-24548 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2022-24548

Vulnerability Analysis

This Denial of Service vulnerability exists within the Microsoft Malware Protection Engine, which is responsible for scanning and detecting malware across Microsoft security products. The vulnerability requires local access and user interaction to exploit, meaning an attacker would need to craft a malicious file that, when scanned by the Malware Protection Engine, causes the service to crash or become unresponsive.

The attack scenario typically involves delivering a specially crafted file to the target system. When Microsoft Defender automatically scans the file—or when a user initiates a manual scan—the malformed content triggers the vulnerability, resulting in a denial of service condition. This could temporarily disable real-time protection features.

Root Cause

The specific technical root cause has not been publicly disclosed by Microsoft (classified as NVD-CWE-noinfo). However, denial of service vulnerabilities in antivirus engines typically arise from improper handling of malformed file structures, parsing errors when processing specially crafted archives, or resource exhaustion conditions triggered by complex or recursive file patterns.

Attack Vector

The attack vector is local, requiring the attacker to either have direct access to the system or to deliver a malicious file that will be scanned by the Malware Protection Engine. User interaction is required for exploitation, typically in the form of opening, downloading, or manually scanning the malicious file. The vulnerability does not require elevated privileges to trigger.

The exploitation mechanism involves crafting a file specifically designed to cause the Malware Protection Engine to malfunction. When the engine processes this file during routine scanning operations, it encounters a condition that leads to service disruption. For detailed technical information, refer to the Microsoft Security Update for CVE-2022-24548.

Detection Methods for CVE-2022-24548

Indicators of Compromise

• Unexpected crashes or restarts of the MsMpEng.exe process (Microsoft Malware Protection Engine)
• Windows Security Center alerts indicating that real-time protection is disabled or not functioning
• Event log entries showing Malware Protection Engine service failures or unexpected terminations
• Presence of suspicious files with unusual structures in recently accessed directories

Detection Strategies

• Monitor Windows Event Logs for Event ID 1001 (Application Error) related to MsMpEng.exe
• Configure alerts for Windows Defender service state changes using Windows Event ID 5007
• Implement file integrity monitoring to detect delivery of potential exploit files
• Deploy endpoint detection solutions to monitor for abnormal behavior patterns in security services

Monitoring Recommendations

• Enable verbose logging for Microsoft Defender to capture detailed scanning activity
• Set up automated alerts when the Malware Protection Engine service stops unexpectedly
• Monitor system resource utilization for anomalies during file scanning operations
• Regularly verify that real-time protection remains active across managed endpoints

How to Mitigate CVE-2022-24548

Immediate Actions Required

• Verify that Microsoft Defender definitions and engine are updated to the latest version
• Enable automatic updates for the Microsoft Malware Protection Engine if not already configured
• Review security policies to ensure real-time protection cannot be easily disabled
• Implement network-level controls to prevent delivery of malicious files

Patch Information

Microsoft has addressed this vulnerability through automatic updates to the Malware Protection Engine. The fix is distributed through Windows Update and Microsoft Defender definition updates. Organizations should verify that their systems are receiving updates and that the Malware Protection Engine version is current.

To check your current engine version, open Windows Security > Settings > About, and verify the Engine version. The vulnerability affects versions prior to the security update released in April 2022. For complete patch details, see the Microsoft Security Update for CVE-2022-24548.

Workarounds

• Ensure automatic updates are enabled for Microsoft Defender to receive the latest engine version
• Configure email gateways and web proxies to scan attachments before they reach endpoints
• Implement application whitelisting to prevent execution of suspicious files
• Deploy network-based malware scanning as a secondary layer of protection

# Verify Microsoft Defender Engine version via PowerShell
Get-MpComputerStatus | Select-Object AMEngineVersion, AMProductVersion, AntispywareEnabled, RealTimeProtectionEnabled

# Force a definition and engine update
Update-MpSignature -UpdateSource MicrosoftUpdateServer

# Verify real-time protection status
Get-MpPreference | Select-Object DisableRealtimeMonitoring