[6] Nmap provides a number of features for probing computer networks, including host discovery and service and operating system detection.

Like any tool, it could potentially be used for black hat hacking,[37] as a precursor to attempts to gain unauthorized access to computer systems.

In 2003 Supreme Court of Finland has ruled that port scanning has amounted to an attempted computer break in, which was illegal under Finnish Penal code at the time:[39]In its ruling the Supreme Court stated that the defendant had systematically carried out port scanning operations to gather information for the purpose of unauthorised break-in to the bank's computer network.

[23] In later releases, Nmap's authors added clarifications and specific interpretations to the license where they felt the GPL was unclear or lacking.

[43][44] In The Matrix Reloaded, Trinity is seen using Nmap to access a power plant's computer system,[45] allowing Neo to "physically" break into a building.

The appearance of Nmap in the film was widely discussed on Internet forums and hailed as an unusually realistic example of hacking.

[46] Nmap and NmapFE were used in The Listening, a 2006 movie about a former NSA officer who defects and mounts a clandestine counter-listening station high in the Italian alps.

The command Nmap is widely used in the video game Hacknet, allowing to probe the network ports of a target system to hack it.