CVE-2022-25435
📋 TL;DR
CVE-2022-25435 is a critical stack overflow vulnerability in Tenda AC9 routers that allows remote attackers to execute arbitrary code by sending specially crafted requests to the SetStaticRoutecfg function. This affects users of Tenda AC9 routers running vulnerable firmware versions. Successful exploitation could lead to complete device compromise.
💻 Affected Systems
- Tenda AC9
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote unauthenticated attacker gains full control of the router, enabling traffic interception, credential theft, network pivoting, and persistent backdoor installation.
Likely Case
Attacker executes arbitrary code with root privileges, potentially creating botnet nodes, intercepting network traffic, or disabling the router.
If Mitigated
With proper network segmentation and firewall rules, impact is limited to the router itself without lateral movement to other network devices.
🎯 Exploit Status
Public proof-of-concept code exists in GitHub repositories. The vulnerability requires no authentication and has straightforward exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Tenda website for latest firmware > v15.03.2.21
Vendor Advisory: https://www.tendacn.com/en/
Restart Required: Yes
Instructions:
1. Visit Tenda official 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 Management
allPrevent external access to router admin interface
Network Segmentation
allIsolate router management interface to trusted network segment
🧯 If You Can't Patch
- Replace affected router with patched or different model
- Implement strict firewall rules blocking all external access to router management interface
🔍 How to Verify
Check if Vulnerable:
Check router firmware version in admin interface under System Status or System ToolsCheck Version:
No CLI command - check via web interface at http://router_ipVerify Fix Applied:
Verify firmware version is newer than v15.03.2.21 after patching📡 Detection & Monitoring
Log Indicators:
- Unusual POST requests to /goform/SetStaticRoutecfg
- Multiple failed exploitation attempts
- Unexpected router reboots
Network Indicators:
- Unusual outbound connections from router
- Traffic patterns suggesting router compromise
SIEM Query:
source="router_logs" AND (uri="/goform/SetStaticRoutecfg" OR message="stack overflow")