CVE-2021-34925
📋 TL;DR
CVE-2021-34925 is a stack-based buffer overflow vulnerability in Bentley View's JT file parser that allows remote code execution. Attackers can exploit this by tricking users into opening malicious JT files or visiting malicious web pages. Users of affected Bentley View versions are vulnerable.
💻 Affected Systems
- Bentley View
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker executing arbitrary code with the same privileges as the Bentley View process, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Malware installation or data exfiltration when users open malicious JT files from untrusted sources.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially only application crash.
🎯 Exploit Status
Exploitation requires user interaction but the vulnerability itself is straightforward to exploit once malicious JT file is crafted.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Bentley View 10.16.0.80 and later
Vendor Advisory: https://www.bentley.com/en/common-vulnerability-exposure/BE-2021-0005
Restart Required: Yes
Instructions:
1. Download latest Bentley View from official Bentley website. 2. Run installer. 3. Restart system after installation completes.
🔧 Temporary Workarounds
Disable JT file association
windowsRemove file type association for .jt files to prevent automatic opening in Bentley View
Windows: Control Panel > Default Programs > Associate a file type or protocol with a program > Select .jt > Change program > Choose different application
Application sandboxing
allRun Bentley View in restricted environment or sandbox
🧯 If You Can't Patch
- Implement strict email filtering for JT file attachments
- Use application control to restrict Bentley View from accessing untrusted network locations
🔍 How to Verify
Check if Vulnerable:
Check Bentley View version in Help > About dialogCheck Version:
Windows: wmic product where name="Bentley View" get versionVerify Fix Applied:
Verify version is 10.16.0.80 or higher after update📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory access violations
- Unexpected process creation from Bentley View
Network Indicators:
- Downloads of JT files from suspicious sources
- Outbound connections from Bentley View to unknown IPs
SIEM Query:
Process Creation where Image contains "BentleyView.exe" and ParentImage not in ("explorer.exe", "cmd.exe")