CVE-2021-34907
📋 TL;DR
CVE-2021-34907 is a heap-based buffer overflow vulnerability in Bentley View's BMP file parser that allows remote code execution. Attackers can exploit this by tricking users into opening malicious BMP files or visiting malicious web pages. Users of affected Bentley View versions are at risk.
💻 Affected Systems
- Bentley View
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining the same privileges as the current user, potentially leading to data theft, ransomware deployment, or lateral movement within the network.
Likely Case
Local privilege escalation or malware installation on the victim's system, potentially leading to data exfiltration or persistence mechanisms.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially only causing application crashes.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) but no authentication. The vulnerability was discovered by Zero Day Initiative (ZDI-CAN-14880).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Bentley View 10.16.0.80 or later
Vendor Advisory: https://www.bentley.com/en/common-vulnerability-exposure/BE-2021-0002
Restart Required: Yes
Instructions:
1. Download latest Bentley View version from official Bentley website. 2. Run installer with administrative privileges. 3. Restart system after installation completes.
🔧 Temporary Workarounds
Disable BMP file association
windowsRemove Bentley View as default handler for BMP files to prevent automatic exploitation
Control Panel > Default Programs > Set Associations > Find .bmp > Change program to non-Bentley application
Application restriction policies
windowsUse AppLocker or similar to restrict Bentley View from opening untrusted files
🧯 If You Can't Patch
- Implement network segmentation to isolate Bentley View systems from critical assets
- Deploy endpoint detection and response (EDR) solutions to monitor for exploitation attempts
🔍 How to Verify
Check if Vulnerable:
Check Bentley View version in Help > About dialog. If version is 10.15.0.75 or earlier, system is vulnerable.Check Version:
Not applicable - check via GUI in Help > AboutVerify Fix Applied:
Verify version is 10.16.0.80 or later in Help > About dialog after patching.📡 Detection & Monitoring
Log Indicators:
- Application crashes of Bentley View with memory access violations
- Unusual process creation from Bentley View executable
Network Indicators:
- Downloads of BMP files from untrusted sources followed by Bentley View execution
SIEM Query:
Process Creation where Image contains 'BentleyView.exe' AND Parent Process contains 'explorer.exe' AND Command Line contains '.bmp'