Malvertising
Websites or web publishers unknowingly incorporate a corrupted or malicious advertisement into their page. Computers can become infected pre-click and post click. It is a misconception that infection only happens when visitors begin clicking on a malvertisement. "Examples of pre-click malware include being embedded in main scripts of the page or drive-by-downloads. Malware can also auto-run, as in the case of auto redirects, where the user is automatically taken to a different site, which could be malicious. Malware can also be found in the delivery of an ad – where a clean ad that has no malware pre or post click (in its build and design) can still be infected whilst being called. Malicious code can hide undetected and the user has no idea what's coming their way. A post-click malvertisement example: "the user clicks on the ad to visit the advertised site, and instead is directly infected or redirected to a malicious site. These sites trick users into copying viruses or spyware usually disguised as Flash files, which are very popular on the web." Redirection is often built into online advertising, and this spread of malware is often successful because users expect a redirection to happen when clicking on an advertisement. A redirection that is taking place only needs to be co-opted in order to infect a user's computer.
Ransomware
The converse of ransomware is a cryptovirology attack invented by Adam L. Young that threatens to publish stolen information from the victim's computer system rather than deny the victim access to it. In a leakware attack, malware exfiltrates sensitive host data either to the attacker or alternatively, to remote instances of the malware, and the attacker threatens to publish the victim's data unless a ransom is paid. The attack was presented at West Point in 2003 and was summarized in the book "Malicious Cryptography" as follows, "The attack differs from the extortion attack in the following way. In the extortion attack, the victim is denied access to its own valuable information and has to pay to get it back, where in the attack that is presented here the victim retains access to the information but its disclosure is at the discretion of the computer virus". The attack is rooted in game theory and was originally dubbed "non-zero sum games and survivable malware". The attack can yield monetary gain in cases where the malware acquires access to information that may damage the victim user or organization, e.g., reputational damage that could result from publishing proof that the attack itself was a success.