Port/Network Scanner: Port scanner is an application designed to probe a server or host for open ports. Port scanning has legitimate uses in managing networks, but port scanning also can be malicious in nature if someone is looking for open ports to break into your computer. Network mapper (Nmap), an open source software is an example of port scanner.
Sniffer: A sniffer is an application that can capture network packets. Sniffers are also known as network protocol analyzers. While protocol analyzers are really network troubleshooting tools, they are also used by hackers for hacking network.
Cipher: A cipher (pronounced SAI-fuhr) is any method of encrypting text (concealing its readability and meaning). Cipher-text is encrypted text. Plain-text is what you have before encryption, and cipher-text is the encrypted result.
Telnet Client: Telnet is a protocol that allows you to connect to remote computers (called hosts) over a TCP/IP network (such as the Internet). Using telnet client software on your computer, you can make a connection to a telnet server (i.e., the remote host).
Anti-malware software: Anti-malware software protects against infections caused by many types of malware, including viruses, worms, Trojan horses, rootkits, spyware, key-loggers, ransomware and adware. Another popular software is anti-virus software. However, anti-virus software is targeted towards removing certain types of malware such as virus. Malware is a generic term given to any harmful software and includes virus.