Though in 2004, the QAZ virus was assessed as being at a low Level 2 threat by Symantec Security Response, the virus (known as W32.HLLW.Qaz.A) was discovered in China in July 2000. The QAZ virus spread over a network through a back door, enabling a remote user to set up a connection to take control over someoneÂ’s computer using port 7597. Because this virus could not be spread to machines outside the network, it may have been initially sent by email. The virus, originally called Qaz.Trojan, was renamed W32.HLLW.Qaz.A on August 10, 2000.

See Also: Back or Trap Door; Electronic Mail or Email; Network; Port and Port Numbers.