(1) Gaining access to a restricted communications channel by using the session another user already established. Piggybacking can be defeated by logging out before walking away from a workstation or terminal or by initiating a screensaver that requires re-authentication when resuming.
Piggybacking also refers to someone allowing another person to follow right after them into a restricted area. Also known as "tailgating," this may be done on purpose by a disgruntled employee or just out of carelessness. See
replay attack,
hijacking and
cryptojacking.
(2) Using a Wi-Fi hotspot of neighbors who have not secured their network. See
Wi-Fi piggybacking and
Wi-Fi hotspot.
(3) Embedding the names of popular brands or companies into the hidden metadata of a Web page in order to rank high up on a search engine's results page. See
meta tag.