This program uses multithreading to scan a range of IP addresses (IPv4) to find telnet/ssh and web servers. It then brute forces credentials against the host and upon success, will detect the type of host and execute commands.
You can download it from the following link: https://packetstormsecurity.com/files/download/113138/TelnetScanner.cs.txt
Source: https://packetstormsecurity.com/files/113138/.NET-Mass-Telnet-SSH-Multithread-Scanner-Botnet-Builder.html