Passwords are perhaps the most sought after target of hackers. Intruding into email might lead to more passwords. For hacking inside a user’s computer, hackers use several techniques like using a Trojan Horse. Downloaded as legitimate software, the Trojan can permanently damage the operating system or can be used to steal passwords.
Apart from this, hackers can also initiate a man-in-the-middle attack when they are able to fool the user into establishing a link with a rouge entity rather than connecting to the legitimate server. The recent denial of service (DoS) attacks carried out on various websites which obstructed WikiLeaks operations were done using similar software which were installed in the computers of various users. While some of them downloaded it voluntarily, others were simply not aware that their computers had software that was being used against these websites.