CVE-2022-25427
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on Tenda AC9 routers via a stack overflow in the openSchedWifi function. Attackers can exploit this by sending specially crafted requests to the schedendtime parameter, potentially gaining full control of affected devices. This affects all users running vulnerable firmware versions.
💻 Affected Systems
- Tenda AC9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise leading to persistent backdoor installation, network traffic interception, credential theft, and use as a pivot point for attacking other internal systems.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept traffic, or use the device as part of a botnet.
If Mitigated
Limited impact if network segmentation prevents lateral movement and external access is restricted.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware
Vendor Advisory: https://www.tendacn.com/en/
Restart Required: Yes
Instructions:
1. Visit Tenda support website. 2. Download latest firmware for AC9. 3. Log into router admin interface. 4. Navigate to System Tools > Firmware Upgrade. 5. Upload and install new firmware. 6. Reboot router.
🔧 Temporary Workarounds
Disable remote administration
allPrevents external attackers from accessing vulnerable interface
Network segmentation
allIsolate router management interface from untrusted networks
🧯 If You Can't Patch
- Replace vulnerable device with patched alternative
- Implement strict firewall rules blocking all external access to router management interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router admin interface under System Status or System ToolsCheck Version:
Login to router web interface and check System Status pageVerify Fix Applied:
Confirm firmware version is newer than v15.03.2.21 after patching📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to router management interface
- Multiple failed exploit attempts
- Unexpected configuration changes
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting command and control communication
SIEM Query:
source="router_logs" AND (uri="*/goform/openSchedWifi" OR uri="*/goform/*") AND method="POST"