CVE-2023-33556
📋 TL;DR
This CVE describes a command injection vulnerability in TOTOLink A7100RU routers that allows attackers to execute arbitrary commands on the device. The vulnerability exists in the staticGw parameter of the /setting/setWanIeCfg endpoint. Anyone using the affected router model with the vulnerable firmware is at risk.
💻 Affected Systems
- TOTOLink A7100RU
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router allowing attackers to establish persistent access, intercept network traffic, pivot to internal networks, and potentially brick the device.
Likely Case
Attackers gain remote code execution on the router, enabling them to modify network settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact with proper network segmentation and firewall rules preventing external access to the management interface.
🎯 Exploit Status
Exploit details are publicly available on GitHub, making exploitation straightforward for attackers with access to the management interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check TOTOLink official website for firmware updates. If available, download and flash the latest firmware through the router's web interface.
🔧 Temporary Workarounds
Disable WAN Management Access
allPrevent external access to the router's management interface
Access router settings → Administration → Remote Management → Disable
Change Default Credentials
allUse strong, unique credentials for router administration
Access router settings → System Tools → Modify Login Password
🧯 If You Can't Patch
- Segment the router on a dedicated network VLAN with strict firewall rules
- Implement network monitoring for unusual traffic patterns or connection attempts to the router
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in web interface: System Tools → Firmware Upgrade → Current VersionCheck Version:
curl -s http://router-ip/ | grep -i firmware || Check web interface manuallyVerify Fix Applied:
Verify firmware version is newer than V7.4cu.2313_B20191024📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /setting/setWanIeCfg
- Commands with shell metacharacters in staticGw parameter
Network Indicators:
- Unexpected outbound connections from router
- Unusual traffic patterns from router IP
SIEM Query:
source="router_logs" AND uri="/setting/setWanIeCfg" AND (staticGw CONTAINS "|" OR staticGw CONTAINS ";" OR staticGw CONTAINS "`")