CVE-2023-40799
📋 TL;DR
CVE-2023-40799 is a critical buffer overflow vulnerability in Tenda AC23 routers that allows remote attackers to execute arbitrary code or cause denial of service. The vulnerability exists in the sub_450A4C function and affects users running firmware version Vv16.03.07.45_cn.
💻 Affected Systems
- Tenda AC23
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full control of the router, enabling network traffic interception, credential theft, and lateral movement into connected networks.
Likely Case
Remote code execution leading to router compromise, allowing attackers to modify DNS settings, intercept traffic, or create persistent backdoors.
If Mitigated
If network segmentation and proper firewall rules are in place, impact may be limited to the router itself without compromising internal networks.
🎯 Exploit Status
Public GitHub repository contains vulnerability details and proof-of-concept code. The high CVSS score and buffer overflow nature make weaponization likely.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: No official vendor advisory found
Restart Required: Yes
Instructions:
1. Check Tenda's official website for firmware updates. 2. If available, download the latest firmware. 3. Access router admin interface. 4. Navigate to firmware upgrade section. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable Remote Management
allPrevent external access to router management interface
Access router admin panel -> System Tools -> Remote Management -> Disable
Network Segmentation
allIsolate router management interface to separate VLAN
🧯 If You Can't Patch
- Replace affected router with different model or vendor
- Implement strict firewall rules to block all external access to router management interface
🔍 How to Verify
Check if Vulnerable:
Access router admin interface and check firmware version. If version is Vv16.03.07.45_cn, device is vulnerable.Check Version:
Check router web interface or use: curl -s http://router-ip/login/AuthVerify Fix Applied:
After firmware update, verify version has changed from Vv16.03.07.45_cn to a newer version.📡 Detection & Monitoring
Log Indicators:
- Unusual buffer overflow errors in router logs
- Multiple failed authentication attempts followed by successful access
- Unexpected firmware modification timestamps
Network Indicators:
- Unusual outbound connections from router
- DNS queries to suspicious domains
- Port scanning originating from router
SIEM Query:
source="router_logs" AND ("buffer overflow" OR "segmentation fault" OR "memory violation")