Hidden Authentication Bypass in Multiple Router Versions
Security Advisory
VU#213560
A critical hidden vulnerability exposed
// Hidden authentication function in tendaWebs binary
// Backdoor bypasses normal login verification
if (strcmp(password, "BACKDOOR_STRING") == 0) {
// Grants admin access without authentication
return AUTH_SUCCESS;
}
// Normal users must provide valid credentials
return verify_credentials(user, password);The firmware's web server binary contains hardcoded authentication bypass logic, allowing attackers to gain full administrative access.
Understanding the scope and protecting your network
AC15, AC18, AC6, AC9, and other Tenda router models affected across various firmware versions
Attackers can remotely access router admin panel, modify DNS settings, and intercept traffic
Compromised router puts all connected devices at risk of data theft and man-in-the-middle attacks
Tenda routers are popular consumer devices, potentially affecting millions of users globally
Identify if you have a Tenda router and check the model number and firmware version
If an update is available from Tenda, apply it immediately to patch the vulnerability
Isolate IoT devices on a separate network to limit potential damage from compromised routers
Evaluate replacing affected Tenda routers with alternatives from vendors with stronger security practices
Consumer router security remains a critical concern. Regular firmware updates and network monitoring are essential for protecting your digital infrastructure.