CVE-2023-41558
📋 TL;DR
CVE-2023-41558 is a critical stack overflow vulnerability in Tenda AC7 routers that allows remote attackers to execute arbitrary code by sending specially crafted requests to the /goform/SetSysTimeCfg endpoint. This affects all users running Tenda AC7 V1.0 firmware version 15.03.06.44. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- Tenda AC7 V1.0
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full control of the router, enabling traffic interception, credential theft, lateral movement to internal networks, and persistent backdoor installation.
Likely Case
Remote code execution leading to router compromise, allowing attackers to modify DNS settings, intercept traffic, or join the device to a botnet.
If Mitigated
If network segmentation and proper firewall rules are in place, impact may be limited to the router itself without lateral movement to other systems.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. Exploitation requires sending a crafted HTTP POST request with malicious timeZone parameter.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates. 2. If update available, download and install via router web interface. 3. Reboot router after installation. 4. Verify firmware version has changed from 15.03.06.44.
🔧 Temporary Workarounds
Disable Web Management Interface
allDisable the router's web management interface to prevent access to vulnerable endpoint
Access router settings → System Tools → Remote Management → Disable
Restrict Web Interface Access
allLimit web interface access to specific trusted IP addresses only
Access router settings → System Tools → Remote Management → Set allowed IP range
🧯 If You Can't Patch
- Isolate router on separate VLAN with strict firewall rules blocking all inbound traffic
- Replace vulnerable router with different model or manufacturer
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface: Login → System Tools → Firmware Upgrade → Current Version should show 15.03.06.44Check Version:
curl -s http://router-ip/goform/getStatus | grep version (if API accessible)Verify Fix Applied:
Verify firmware version has changed from 15.03.06.44 to a newer version📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to /goform/SetSysTimeCfg with unusually long timeZone parameter
- Router reboot events or configuration changes
Network Indicators:
- Unusual outbound connections from router IP
- DNS changes or unexpected traffic redirection
SIEM Query:
source="router_logs" AND url="/goform/SetSysTimeCfg" AND parameter="timeZone" AND length(parameter_value) > 100