CVE-2023-27076
📋 TL;DR
This critical command injection vulnerability in Tenda G103 routers allows attackers to execute arbitrary system commands by manipulating the language parameter. Attackers can gain complete control of affected routers, potentially compromising all network traffic. Anyone using Tenda G103 routers with vulnerable firmware is affected.
💻 Affected Systems
- Tenda G103
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise leading to full network traffic interception, credential theft, lateral movement to connected devices, and persistent backdoor installation.
Likely Case
Router takeover allowing DNS hijacking, credential harvesting, and use as pivot point for attacks on internal network devices.
If Mitigated
Limited impact if router is behind firewall with strict inbound rules and network segmentation prevents lateral movement.
🎯 Exploit Status
Public exploit details available in GitHub repository. Simple HTTP request with crafted language parameter can trigger exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: No
Instructions:
Check Tenda official website for firmware updates. If no patch available, consider replacing router with supported model.
🔧 Temporary Workarounds
Disable WAN Management
allPrevent external access to router management interface
Access router admin panel > Security > Remote Management > Disable
Network Segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace router with supported model that receives security updates
- Place router behind dedicated firewall with strict inbound rules blocking all unnecessary ports
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin panel. If version is exactly 1.0.0.5, device is vulnerable.Check Version:
Login to router admin interface and check System Status or Firmware Update sectionVerify Fix Applied:
Verify firmware version has been updated to a version higher than 1.0.0.5📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to language parameter
- Unexpected system command execution in router logs
- Failed authentication attempts followed by successful exploitation
Network Indicators:
- HTTP POST requests with shell metacharacters in language parameter
- Outbound connections from router to suspicious IPs
- DNS queries to malicious domains
SIEM Query:
source="router_logs" AND ("language=" AND ("|" OR ";" OR "$" OR "`"))