CVE-2021-41552
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on CommScope SURFboard SBG6950AC2 devices via command injection. It affects users of these specific cable modem/router devices running vulnerable firmware versions. Attackers can potentially take full control of the device.
💻 Affected Systems
- CommScope SURFboard SBG6950AC2
📦 What is this software?
Arris Surfboard Sbg10 Firmware by Commscope
Arris Surfboard Sbg6950ac2 Firmware by Commscope
View all CVEs affecting Arris Surfboard Sbg6950ac2 Firmware →
Arris Surfboard Sbg7400ac2 Firmware by Commscope
View all CVEs affecting Arris Surfboard Sbg7400ac2 Firmware →
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to intercept all network traffic, install persistent malware, pivot to internal networks, and use device as botnet node.
Likely Case
Device takeover leading to DNS hijacking, credential theft from network traffic, and denial of service to connected devices.
If Mitigated
Limited impact if device is behind firewall with restricted WAN access and network segmentation prevents lateral movement.
🎯 Exploit Status
Command injection vulnerabilities typically have low exploitation complexity, especially if unauthenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor for latest firmware
Vendor Advisory: https://arris.my.salesforce.com/sfc/p/#30000000kUAL/a/4Q000000Raud/cRx46eSijpwhTpoeWSgB1dQehSMwFrLV1gurcqI35QY
Restart Required: Yes
Instructions:
1. Log into device admin interface. 2. Navigate to firmware update section. 3. Download latest firmware from CommScope support site. 4. Upload and apply firmware update. 5. Reboot device.
🔧 Temporary Workarounds
Network Segmentation
allPlace device in isolated network segment to limit potential damage if compromised.
Access Restriction
allRestrict administrative access to trusted IP addresses only.
🧯 If You Can't Patch
- Replace vulnerable device with patched or different model
- Implement strict network monitoring and anomaly detection for device traffic
🔍 How to Verify
Check if Vulnerable:
Check firmware version in device admin interface under System Status or similar section.Check Version:
Login to device web interface and navigate to System Status pageVerify Fix Applied:
Verify firmware version has been updated to a version later than 9.1.103AA23.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Multiple failed login attempts followed by successful access
- Unexpected process execution
Network Indicators:
- Unusual outbound connections from device
- DNS queries to suspicious domains
- Unexpected port scans originating from device
SIEM Query:
source="router_logs" AND ("command injection" OR "unauthorized access" OR "shell execution")