TFTP

TFTP (Trivial File Transfer Protocol) runs on UDP port 69 and provides a minimal file transfer service with no authentication. Nmap identifies it as tftp. It is commonly used for PXE boot images, firmware updates, and network device configurations.

TFTP has no access control by design. If a TFTP server is exposed, any file within the configured root directory can be downloaded, and in some cases uploaded. This often includes router and switch configuration files containing credentials, SNMP community strings, and network topology details.

Use a TFTP client or nmap --script tftp-enum to check for accessible files. Try common filenames like configuration backups, boot images, and running-config dumps. If write access is enabled, file upload can lead to further compromise.