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.
AutoRun
AutoRun malware has been extended to use hard drives, picture frames and other digital devices. Care in dealing with external devices is a security priority. The prevalence of malware infection by means of AutoRun and USB flash drive was documented in a 2011 Microsoft study analyzing data from more than 600 million systems worldwide in the first half of 2011. The study found that 26 percent of all malware infections of Windows system were due to USB flash drives exploiting the AutoRun feature in Microsoft Windows. That finding was in line with other statistics, such as the monthly reporting of most commonly detected malware by antivirus company ESET, which lists abuse of autorun.inf as first among the top ten threats in 2011.