CVE-2025-6939
📋 TL;DR
A critical buffer overflow vulnerability in TOTOLINK A3002RU routers allows remote attackers to execute arbitrary code by sending specially crafted HTTP POST requests to the /boafrm/formWlSiteSurvey endpoint. This affects TOTOLINK A3002RU routers running firmware version 3.0.0-B20230809.1615. Attackers can exploit this without authentication to potentially take full control of affected devices.
💻 Affected Systems
- TOTOLINK A3002RU
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, lateral movement to internal networks, persistent backdoor installation, and botnet recruitment.
Likely Case
Remote code execution allowing attackers to modify router settings, intercept network traffic, or use the device as a pivot point for further attacks.
If Mitigated
Denial of service or limited information disclosure if exploit attempts are blocked by network controls.
🎯 Exploit Status
Public exploit code is available on GitHub. The vulnerability requires no authentication and has straightforward exploitation steps.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.totolink.net/
Restart Required: Yes
Instructions:
1. Check TOTOLINK website for firmware updates. 2. Download latest firmware for A3002RU. 3. Access router web interface. 4. Navigate to firmware upgrade section. 5. Upload new firmware file. 6. Wait for reboot and verify version.
🔧 Temporary Workarounds
Disable Web Management Interface
allDisable the router's web management interface to prevent HTTP-based exploitation.
Access router CLI via SSH/Telnet
Navigate to web interface settings
Disable HTTP/HTTPS management
Network Segmentation
allIsolate affected routers in separate VLANs with strict firewall rules.
Configure firewall to block external access to router management ports
Create separate VLAN for router management
🧯 If You Can't Patch
- Block external access to router management ports (80, 443, 8080) at network perimeter
- Implement strict network segmentation to limit router exposure to trusted networks only
🔍 How to Verify
Check if Vulnerable:
Check router firmware version via web interface at System Status > Firmware Version. If version is 3.0.0-B20230809.1615, device is vulnerable.Check Version:
curl -s http://router-ip/boafrm/formSysCmd | grep FirmwareVerify Fix Applied:
After firmware update, verify version has changed from 3.0.0-B20230809.1615 to a newer version.📡 Detection & Monitoring
Log Indicators:
- Multiple POST requests to /boafrm/formWlSiteSurvey
- Unusual buffer overflow errors in router logs
- Failed authentication attempts followed by POST requests
Network Indicators:
- HTTP POST requests to /boafrm/formWlSiteSurvey with long submit-url parameters
- Unusual outbound connections from router after exploitation
SIEM Query:
source="router_logs" AND (uri="/boafrm/formWlSiteSurvey" OR message="buffer overflow")