Zte F680 Exploit – Confirmed

However, like many ISP-provided hardware devices, the ZTE F680 has become a frequent target for security researchers and malicious actors alike. The term refers to a collection of vulnerabilities that allow an attacker to bypass authentication, gain root access, and potentially use the router as a pivot point for larger network attacks.

POST /cgi-bin/telnet.cgi HTTP/1.1 Host: 192.168.1.1 Cookie: language=english; enabled=1 Content-Length: 50 enable telnet=1&username=admin&password=admin zte f680 exploit

Security researcher Pierre Kim documented in 2021 that the ZTE F680’s firmware contains hardcoded RSA private keys for SSH, allowing anyone with the key to decrypt LAN traffic or impersonate the device. Let’s walk through a realistic exploit chain used by botnets (like Mirai variants) and red-teamers against the ZTE F680. Phase 1: Discovery & Fingerprinting The attacker scans for devices responding on port 80 or 443 with a specific HTTP title: ZTE F680 GPON ONT . The default login page often leaks the firmware version in the HTML source code. Phase 2: Authentication Bypass Using a simple Python script, the attacker sends a POST request to /cgi-bin/telnet.cgi with no session cookie. If the device is vulnerable, the response 200 OK appears, and Telnet is enabled on port 23. However, like many ISP-provided hardware devices, the ZTE

This results in Remote Code Execution (RCE) with root privileges, as the web server runs with high system privileges. While not a "software bug" per se, many ISPs never change the manufacturer default passwords. However, the ZTE F680 has a known hidden backdoor: the user account with password Zte521 (or variations like root / Zte521@hn ). These accounts bypass the standard login lockout policies, making brute-forcing trivial. Let’s walk through a realistic exploit chain used