CVE-2023-25395
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary commands on TOTOlink A7100RU routers via command injection in the 'ou' parameter. Attackers can gain full control of affected routers, potentially compromising network security. Only users of specific TOTOlink router models with vulnerable firmware are affected.
💻 Affected Systems
- TOTOlink A7100RU
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise leading to network takeover, credential theft, malware deployment, and use as pivot point for internal network attacks.
Likely Case
Router compromise allowing traffic interception, DNS manipulation, credential harvesting, and persistent backdoor installation.
If Mitigated
Limited impact if router is behind firewall with restricted WAN access and proper network segmentation.
🎯 Exploit Status
Simple HTTP POST request with crafted 'ou' parameter can trigger command execution; no authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Check TOTOlink website for firmware updates. If update exists: 1. Download latest firmware from vendor site 2. Access router admin interface 3. Navigate to firmware update section 4. Upload and apply new firmware 5. Reboot router.
🔧 Temporary Workarounds
Network Segmentation
allIsolate router management interface from untrusted networks
Access Control Lists
linuxRestrict access to router management interface to trusted IPs only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_IP -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
🧯 If You Can't Patch
- Replace vulnerable router with different model/brand
- Place router behind dedicated firewall with strict inbound rules
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface. If version matches V7.4cu.2313_B20191024, assume vulnerable.Check Version:
curl -s http://router-ip/ | grep -i firmware || Check router web interface System Status pageVerify Fix Applied:
Verify firmware version has changed from vulnerable version. Test with controlled command injection attempt (e.g., ping to controlled server).📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /setting/delStaticDhcpRules
- Commands with shell metacharacters in 'ou' parameter
- Unexpected process execution from web server
Network Indicators:
- HTTP requests with shell commands in parameters
- Outbound connections from router to unexpected destinations
- DNS queries for command-and-control domains
SIEM Query:
source="router_logs" AND uri="/setting/delStaticDhcpRules" AND (ou="*;*" OR ou="*|*" OR ou="*`*" OR ou="*$(*")