CVE-2021-34876
📋 TL;DR
CVE-2021-34876 is a buffer overflow vulnerability in Bentley View's JT file parser that allows remote code execution. Attackers can exploit it by tricking users into opening malicious JT files, potentially compromising affected systems. Users of Bentley View 10.15.0.75 are primarily affected.
💻 Affected Systems
- Bentley View
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with attacker gaining full control of the affected machine, data theft, ransomware deployment, and lateral movement within the network.
Likely Case
Local privilege escalation leading to data exfiltration, installation of backdoors, or use as an initial access vector for broader attacks.
If Mitigated
Limited impact with proper application sandboxing and user privilege restrictions, potentially resulting in application crash only.
🎯 Exploit Status
Exploitation requires user interaction but is technically straightforward once malicious file is opened. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 10.16.0.80 or later
Vendor Advisory: https://www.bentley.com/en/common-vulnerability-exposure/BE-2021-0005
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 JT file association
windowsRemove Bentley View as default handler for .jt files to prevent automatic exploitation
Control Panel > Default Programs > Associate a file type or protocol with a program > Select .jt > Change program > Choose another application
Application sandboxing
windowsRun Bentley View in restricted environment using application control solutions
🧯 If You Can't Patch
- Implement strict network segmentation to isolate Bentley View systems
- Deploy application whitelisting to prevent execution of unauthorized code
🔍 How to Verify
Check if Vulnerable:
Check Bentley View version in Help > About. If version is 10.15.0.75, system is vulnerable.Check Version:
wmic product where name="Bentley View" get versionVerify Fix Applied:
Verify version is 10.16.0.80 or later in Help > About menu.📡 Detection & Monitoring
Log Indicators:
- Application crashes with memory access violations
- Unusual process spawning from Bentley View executable
- Failed attempts to open corrupted JT files
Network Indicators:
- Downloads of JT files from untrusted sources
- Outbound connections from Bentley View to unknown IPs
SIEM Query:
source="windows" AND (process_name="BentleyView.exe" AND (event_id=1000 OR event_id=1001))