Wild refers to a situation where a virus or worm has been released and is therefore able to infect computers during normal operation. Viruses and worms released into the wild are the only ones which cause mass damage.
Non-wild or "Zoo" viruses and worms are confined to laboratories or hobby computers and networks. Proof-of-concept viruses and worms, such as those created by ethical groups or writers like 29A or Gigabyte are also rarely released into the wild.
Reasons for Release
The reasons for releasing a virus or worm into the wild are as different as their creators. Many of the early worms and viruses like Morris and Joe Dellinger's virus were released because a part of an experiment required it. Others like Creeper and Elk-Cloner were released as pranks. The creator of Animal simply wanted to share a game he had coded and did not even think that what he was releasing was something that would be considered a precursor to more destructive code.
The Internet opened many more possibilities for using viruses and worms to spread messages, commit fraud on an international scale and even destroy the economic and military assets of foreign nations. Hazafi, Sadmind and many worms and viruses carried political messages. Dumaru and Sobig dropped trojans to steal information. Zhelatin created the powerful Storm botnet for relaying spam. Stuxnet has been confirmed as a weapon, while the Duqu and Flame trojans are suspected to be similar. For many programs, the reason they went wild in the first place is unknown as they have no message or criminal payload, as is the case with the Slammer worm.
Search Security, DEFINITION in the wild.