CVE-2021-31983: Microsoft Paint 3D RCE Vulnerability

CVE-2021-31983 Overview

CVE-2021-31983 is a Remote Code Execution (RCE) vulnerability affecting Microsoft Paint 3D, the 3D modeling and creative application bundled with Windows 10. This vulnerability allows an attacker to execute arbitrary code on a victim's system when a user opens a specially crafted malicious file within the Paint 3D application.

Critical Impact

Successful exploitation of this vulnerability could allow an attacker to execute arbitrary code in the context of the current user, potentially leading to complete system compromise, data theft, or installation of malware.

Affected Products

• Microsoft Paint 3D (all versions prior to security update)

Discovery Timeline

• 2021-06-08 - CVE CVE-2021-31983 published to NVD
• 2024-11-21 - Last updated in NVD database

Technical Details for CVE-2021-31983

Vulnerability Analysis

This Remote Code Execution vulnerability in Microsoft Paint 3D requires local access and user interaction to exploit. An attacker must convince a user to open a maliciously crafted file using the Paint 3D application. Once the victim opens the file, the attacker's code executes with the same privileges as the logged-in user.

The vulnerability has been assigned CWE category "NVD-CWE-noinfo," indicating that specific weakness enumeration details were not disclosed in the public advisory, likely to prevent exploitation details from becoming widely available before users could apply patches.

Root Cause

While Microsoft has not disclosed the specific technical root cause, the vulnerability exists within Paint 3D's file parsing functionality. The application fails to properly validate or sanitize input when processing certain file types, allowing specially crafted files to trigger arbitrary code execution during the parsing process.

Attack Vector

The attack vector for CVE-2021-31983 is local, requiring user interaction. The typical attack scenario involves:

1. An attacker creates a specially crafted 3D model file or project file compatible with Paint 3D
2. The malicious file is delivered to the victim via email attachment, malicious website download, or file-sharing service
3. The victim opens the file using Paint 3D
4. The vulnerability is triggered during file parsing, executing the attacker's code

The attack requires no privileges but does require the victim to actively open the malicious file. This is a common social engineering attack pattern where users are tricked into opening files that appear legitimate.

For technical implementation details, refer to the Zero Day Initiative Advisory ZDI-21-658.

Detection Methods for CVE-2021-31983

Indicators of Compromise

• Unusual Paint 3D process activity, such as PaintStudio.View.exe spawning unexpected child processes
• Paint 3D attempting to access system resources or files outside its normal scope
• Suspicious network connections initiated by Paint 3D processes
• Presence of malformed or suspicious .3mf, .fbx, .obj, .ply, .stl, or .glb files recently opened by users

Detection Strategies

• Monitor process execution chains for Paint 3D (PaintStudio.View.exe) spawning command shells, PowerShell, or other suspicious child processes
• Implement file scanning for potentially malicious 3D model files before they reach end users
• Deploy endpoint detection rules to alert on anomalous behavior from Windows Store applications
• Use behavioral analysis to detect code execution patterns inconsistent with normal Paint 3D operations

Monitoring Recommendations

• Enable Windows Event logging for application crash events related to Paint 3D
• Configure SentinelOne agents to monitor for exploitation attempts targeting Paint 3D processes
• Review endpoint telemetry for suspicious file downloads followed by Paint 3D execution
• Implement email attachment scanning for 3D model file formats commonly used by Paint 3D

How to Mitigate CVE-2021-31983

Immediate Actions Required

• Apply the latest security updates for Microsoft Paint 3D from the Microsoft Store
• Restrict execution of Paint 3D in high-security environments where 3D modeling is not required
• Educate users about the risks of opening 3D model files from untrusted sources
• Consider uninstalling Paint 3D on systems where it is not needed

Patch Information

Microsoft has released a security update addressing CVE-2021-31983. The patch is distributed through the Microsoft Store and should be applied immediately. Users should ensure that automatic updates are enabled for Microsoft Store applications.

For detailed patch information, refer to the Microsoft Security Advisory CVE-2021-31983.

Workarounds

• Uninstall Paint 3D if it is not required for business operations using Get-AppxPackage *Microsoft.MSPaint3D* | Remove-AppxPackage in PowerShell
• Block opening of 3D model file types from external sources via email filtering and web proxy policies
• Use application control policies to restrict Paint 3D execution to authorized users only
• Implement network segmentation to limit lateral movement if exploitation occurs

# PowerShell command to uninstall Paint 3D
Get-AppxPackage -Name "Microsoft.MSPaint3D" | Remove-AppxPackage

# Alternatively, for all users on the system
Get-AppxPackage -AllUsers -Name "Microsoft.MSPaint3D" | Remove-AppxPackage