CVE-2021-40410
📋 TL;DR
This CVE describes an OS command injection vulnerability in Reolink RLC-410W IP cameras. Attackers can execute arbitrary commands on the device by injecting malicious payloads into the DNS1 parameter of the SetLocal API. This affects users of Reolink RLC-410W cameras running vulnerable firmware versions.
💻 Affected Systems
- Reolink RLC-410W
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full device compromise allowing attackers to execute arbitrary commands, install malware, pivot to internal networks, or render the camera inoperable.
Likely Case
Attackers gain shell access to the camera, potentially enabling surveillance disruption, credential theft, or using the device as a foothold for lateral movement.
If Mitigated
Limited impact if cameras are isolated on separate VLANs with strict network segmentation and no internet exposure.
🎯 Exploit Status
Exploitation requires network access to the camera's API but no authentication. The vulnerability is well-documented in public advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version after v3.0.0.136_20121102
Vendor Advisory: https://talosintelligence.com/vulnerability_reports/TALOS-2021-1424
Restart Required: Yes
Instructions:
1. Log into Reolink web interface. 2. Navigate to System > Maintenance. 3. Check for firmware updates. 4. Download and install latest firmware. 5. Reboot camera after installation.
🔧 Temporary Workarounds
Network Segmentation
allIsolate cameras on separate VLAN with strict firewall rules
API Access Restriction
linuxBlock external access to camera management interfaces
iptables -A INPUT -p tcp --dport 80 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Segment cameras on isolated network with no internet access
- Implement strict firewall rules to block all inbound traffic to camera management interfaces
🔍 How to Verify
Check if Vulnerable:
Check firmware version in camera web interface under System > Device InformationCheck Version:
curl -s http://camera-ip/cgi-bin/api.cgi?cmd=GetDevInfo | grep -i versionVerify Fix Applied:
Verify firmware version is newer than v3.0.0.136_20121102 and test SetLocal API with sanitized inputs📡 Detection & Monitoring
Log Indicators:
- Unusual DNS configuration changes
- Suspicious command execution in system logs
- Multiple failed API authentication attempts
Network Indicators:
- Unusual outbound connections from camera
- DNS queries to malicious domains
- Unexpected traffic on non-standard ports
SIEM Query:
source="camera_logs" AND (dns1="*;*" OR dns1="*|*" OR dns1="*`*" OR dns1="*$(*")