CVE-2021-27381
📋 TL;DR
This vulnerability in Solid Edge CAD software allows attackers to execute arbitrary code by exploiting improper validation of PAR files. Users of Solid Edge SE2020 and SE2021 before specific maintenance packs are affected. The out-of-bounds read can lead to remote code execution in the current process context.
💻 Affected Systems
- Solid Edge SE2020
- Solid Edge SE2021
📦 What is this software?
Solid Edge by Siemens
Solid Edge by Siemens
Solid Edge by Siemens
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local privilege escalation or arbitrary code execution when a user opens a malicious PAR file, potentially compromising the workstation.
If Mitigated
Limited impact with proper file validation and user awareness, potentially only causing application crashes.
🎯 Exploit Status
Exploitation requires user interaction to open a malicious PAR file. No public exploit code is known at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Solid Edge SE2020 Maintenance Pack 13 (SE2020MP13) or later, Solid Edge SE2021 Maintenance Pack 3 (SE2021MP3) or later
Vendor Advisory: https://cert-portal.siemens.com/productcert/pdf/ssa-715184.pdf
Restart Required: Yes
Instructions:
1. Download the appropriate maintenance pack from Siemens support portal. 2. Close all Solid Edge applications. 3. Run the maintenance pack installer. 4. Restart the system.
🔧 Temporary Workarounds
Block PAR file execution
windowsPrevent Solid Edge from opening PAR files via group policy or application restrictions
Use Windows Group Policy to block .par file associations with Solid Edge
User awareness training
allEducate users to avoid opening PAR files from untrusted sources
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized Solid Edge execution
- Use network segmentation to isolate CAD workstations from critical systems
🔍 How to Verify
Check if Vulnerable:
Check Solid Edge version in Help > About Solid Edge. If version is SE2020 before MP13 or SE2021 before MP3, system is vulnerable.Check Version:
In Solid Edge: Help > About Solid EdgeVerify Fix Applied:
Verify version shows SE2020MP13 or later, or SE2021MP3 or later in Help > About Solid Edge.📡 Detection & Monitoring
Log Indicators:
- Application crashes in Solid Edge when opening PAR files
- Unexpected process creation from sedge.exe
Network Indicators:
- Downloads of PAR files from untrusted sources
- Unusual outbound connections from CAD workstations
SIEM Query:
Process Creation: sedge.exe AND File Extension: .par