Once an attacker manages to hack and gain access to a target site or system, they typically work hard to maintain their access—as long as it can to help them achieve their goals.
You can think of it like having an annoying party-crasher at your pool party who decides to stick around uninvited, hiding out somewhere and using all of your stuff.
In a large majority of hacked sites, attackers often plant and place something called a backdoor.
Continue reading The Hacker Returns: A Backdoor Edition at Sucuri Blog.
Source: Sucuri
