CVE-2022-25556
📋 TL;DR
Tenda AX12 routers running firmware v22.03.01.21 contain a stack overflow vulnerability in the sub_42E328 function. Attackers can exploit this via the list parameter to cause a Denial of Service (DoS), potentially crashing the device. This affects all users of the vulnerable firmware version.
💻 Affected Systems
- Tenda AX12
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash requiring physical reboot, potentially disrupting all network services and connectivity for connected devices.
Likely Case
Router becomes unresponsive, requiring manual reboot to restore functionality, causing temporary network outage.
If Mitigated
If properly segmented and firewalled, impact limited to router management interface with minimal network disruption.
🎯 Exploit Status
Proof-of-concept code is publicly available in GitHub repositories. Exploitation requires network access to the router's management interface.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not publicly available
Restart Required: Yes
Instructions:
1. Check Tenda website for firmware updates
2. If update available, download and install via web interface
3. Reboot router after installation
🔧 Temporary Workarounds
Disable remote management
allPrevent external access to router management interface
Access router web interface > Advanced > System Tools > Remote Management > Disable
Restrict management interface access
allLimit management interface to trusted IP addresses only
Access router web interface > Advanced > Security > Access Control > Add trusted IP ranges
🧯 If You Can't Patch
- Replace router with different model or vendor
- Isolate router on separate network segment with strict firewall rules
🔍 How to Verify
Check if Vulnerable:
Check firmware version in router web interface: Login > Advanced > System Status > Firmware VersionCheck Version:
Check via web interface or SSH if enabled: cat /proc/versionVerify Fix Applied:
Verify firmware version is no longer v22.03.01.21 after update📡 Detection & Monitoring
Log Indicators:
- Multiple malformed requests to /goform/ endpoint
- Router crash/reboot events in system logs
Network Indicators:
- Unusual HTTP POST requests with long list parameters to router IP
- Sudden loss of router responsiveness
SIEM Query:
source="router_logs" AND ("sub_42E328" OR "list parameter overflow" OR "router crash")