CVE-2021-4199
📋 TL;DR
This vulnerability allows a local attacker to escalate privileges to SYSTEM by exploiting incorrect permissions in BDReinit.exe, Bitdefender's crash handling component. It affects multiple Bitdefender security products for Windows. Successful exploitation gives an attacker complete control over the affected system.
💻 Affected Systems
- Bitdefender Total Security
- Bitdefender Internet Security
- Bitdefender Antivirus Plus
- Bitdefender Endpoint Security Tools for Windows
📦 What is this software?
Antivirus Plus by Bitdefender
Internet Security by Bitdefender
Total Security by Bitdefender
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with SYSTEM privileges, allowing installation of persistent malware, credential theft, and lateral movement across the network.
Likely Case
Local privilege escalation from a standard user account to SYSTEM, enabling full administrative control of the local machine.
If Mitigated
Limited impact if proper access controls and least privilege principles are already implemented, though SYSTEM access remains a significant risk.
🎯 Exploit Status
Exploitation requires local access but is considered low complexity. While no public PoC exists, the vulnerability details are public and weaponization is likely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Total Security/Internet Security/Antivirus Plus: 26.0.10.45 or later; Endpoint Security Tools: 7.4.3.146 or later
Vendor Advisory: https://www.bitdefender.com/support/security-advisories/incorrect-permission-assignment-for-critical-resource-vulnerability-in-bdreinit-exe-va-10017/
Restart Required: Yes
Instructions:
1. Open Bitdefender interface. 2. Check for updates in the Update section. 3. Install all available updates. 4. Restart the computer when prompted. 5. Verify the version matches or exceeds the patched versions.
🔧 Temporary Workarounds
Restrict BDReinit.exe permissions
windowsManually adjust permissions on BDReinit.exe to prevent unauthorized access
icacls "C:\Program Files\Bitdefender\Bitdefender Security\bdreinit.exe" /inheritance:r /grant:r "SYSTEM:(F)" /grant:r "Administrators:(F)" /deny "Users:(M)" /deny "Everyone:(M)"
🧯 If You Can't Patch
- Implement strict least privilege principles and limit local user access to affected systems
- Monitor for suspicious process creation events related to BDReinit.exe and privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check Bitdefender version in the application interface or via 'wmic product get name,version' and compare against vulnerable versionsCheck Version:
wmic product where "name like '%Bitdefender%'" get name,versionVerify Fix Applied:
Verify the installed version is 26.0.10.45 or later for consumer products, or 7.4.3.146 or later for Endpoint Security Tools📡 Detection & Monitoring
Log Indicators:
- Unusual process creation events for BDReinit.exe
- Privilege escalation attempts from standard user to SYSTEM
- Multiple crash reports from Bitdefender components
Network Indicators:
- None - this is a local privilege escalation vulnerability
SIEM Query:
Process creation where (process_name contains 'bdreinit.exe' AND parent_process not in ('bdservicehost.exe', 'bdagent.exe')) OR (privilege_escalation from user to SYSTEM)🔗 References
- https://www.bitdefender.com/support/security-advisories/incorrect-permission-assignment-for-critical-resource-vulnerability-in-bdreinit-exe-va-10017/
- https://www.zerodayinitiative.com/advisories/ZDI-22-484/
- https://www.bitdefender.com/support/security-advisories/incorrect-permission-assignment-for-critical-resource-vulnerability-in-bdreinit-exe-va-10017/
- https://www.zerodayinitiative.com/advisories/ZDI-22-484/
