Malvertising is the use of online advertising

Online advertising

Online advertising is a form of promotion that uses the Internet and World Wide Web to deliver marketing messages to attract customers. Examples of online advertising include contextual ads on search engine results pages, banner ads, blogs, Rich Media Ads, Social network advertising, interstitial...

 to spread malware

Malware

Malware, short for malicious software, consists of programming that is designed to disrupt or deny operation, gather information that leads to loss of privacy or exploitation, or gain unauthorized access to system resources, or that otherwise exhibits abusive behavior...

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Because advertising content can be inserted into high-profile reputable websites, malvertising provides malefactors an opportunity to "push" their attacks at cautious web users who would not normally visit unknown external URLs, by exploiting the reputation of the website and the allegedly advertised brand

Brand

The American Marketing Association defines a brand as a "Name, term, design, symbol, or any other feature that identifies one seller's good or service as distinct from those of other sellers."...

s to convince them that they are visiting legitimate advertisements. In several cases, the victim need not follow the links presented. Instead, the malicous ad contains a drive-by download

Drive-by download

Drive-by download means three things, each concerning the unintended download of computer software from the Internet:# Downloads which a person authorized but without understanding the consequences Drive-by download means three things, each concerning the unintended download of computer software...

 by using flash

Adobe Flash

Adobe Flash is a multimedia platform used to add animation, video, and interactivity to web pages. Flash is frequently used for advertisements, games and flash animations for broadcast...

scripts.