CVE-2021-47799
📋 TL;DR
Visual Tools DVR VX16 version 4.2.28 contains a local privilege escalation vulnerability in its Sudo configuration. Attackers with local access can exploit unsafe Sudo settings to gain root privileges by using mount commands to bind a shell. This affects systems running the vulnerable DVR software version.
💻 Affected Systems
- Visual Tools DVR VX16
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root access, allowing attackers to install persistent malware, exfiltrate all data, disable security controls, and pivot to other systems.
Likely Case
Local attackers gaining root privileges to modify system configurations, access sensitive DVR recordings, and maintain persistence on the system.
If Mitigated
Limited impact with proper access controls and monitoring, though local privilege escalation remains possible if vulnerable software is present.
🎯 Exploit Status
Exploit requires local user access. The exploit is publicly available on Exploit-DB (ID 50104) and demonstrates simple command execution to gain root.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://visual-tools.com/
Restart Required: No
Instructions:
Check vendor website for security updates. If no patch is available, apply workarounds immediately.
🔧 Temporary Workarounds
Secure Sudo Configuration
linuxModify the Sudo configuration to remove unsafe mount command permissions for non-root users
sudo visudo
Remove or restrict mount command permissions for DVR users in sudoers file
Restrict Local Access
allLimit local user access to DVR systems to authorized personnel only
🧯 If You Can't Patch
- Isolate affected DVR systems on separate network segments with strict access controls
- Implement strict user access controls and monitor for suspicious privilege escalation attempts
🔍 How to Verify
Check if Vulnerable:
Check if Visual Tools DVR VX16 version 4.2.28 is installed and review sudoers configuration for unsafe mount command permissionsCheck Version:
Check DVR software version through administration interface or package managerVerify Fix Applied:
Verify sudoers configuration no longer allows non-root users to execute mount commands with dangerous options📡 Detection & Monitoring
Log Indicators:
- Sudo command executions for mount with bind options
- Unexpected privilege escalation attempts
- Root shell spawns from non-root users
Network Indicators:
- Unusual outbound connections from DVR system after local access
SIEM Query:
source="sudo" AND command="mount" AND options="*bind*"