CVE-2023-40801
📋 TL;DR
CVE-2023-40801 is a stack overflow vulnerability in Tenda AC23 routers caused by improper input validation in the sub_451784 function. Attackers can exploit this to execute arbitrary code with root privileges on affected devices. This affects Tenda AC23 router users running vulnerable firmware versions.
💻 Affected Systems
- Tenda AC23
📦 What is this software?
Ac23 by Tenda
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the router with root access, allowing attackers to intercept traffic, modify DNS settings, install persistent malware, and pivot to internal networks.
Likely Case
Remote code execution leading to router takeover, enabling attackers to create backdoors, steal credentials, or launch attacks against internal devices.
If Mitigated
Limited impact if the router is behind a firewall with strict inbound rules and network segmentation is properly implemented.
🎯 Exploit Status
Public proof-of-concept code is available on GitHub. The vulnerability requires no authentication and has straightforward exploitation due to the stack overflow nature.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. Download the latest firmware for AC23. 3. Access router admin panel. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install the new firmware. 6. Reboot the router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevents external exploitation by disabling remote administration features
Network Segmentation
allPlace router in isolated network segment to limit lateral movement if compromised
🧯 If You Can't Patch
- Replace affected Tenda AC23 router with a different model from a vendor with better security track record
- Implement strict firewall rules to block all inbound traffic to the router except essential management from trusted IPs
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin panel. If version is v16.03.07.45_cn or earlier, assume vulnerable.Check Version:
Login to router admin panel and check System Status or Firmware Version pageVerify Fix Applied:
Verify firmware version has been updated to a version later than v16.03.07.45_cn. Check Tenda security advisories for confirmation.📡 Detection & Monitoring
Log Indicators:
- Unusual process execution on router
- Unexpected firmware modification attempts
- Multiple failed exploit attempts in logs
Network Indicators:
- Unusual outbound connections from router
- DNS hijacking patterns
- Traffic redirection to suspicious IPs
SIEM Query:
source="router_logs" AND ("sub_451784" OR "stack overflow" OR "buffer overflow")