Media sites, including the New York Times, have become the latest targets of attackers who make their living by poisoning online ads and redirecting unsuspecting visitors to malicious Web pages or trying to trick them into downloading malware. Over the weekend attackers were able to buy ads on The Times main site and use the ads in a scareware scheme designed to plant malware on users PCs. The incident is a major embarrassment for the Times, which addressed the attack in a story on Tuesday. Many online ads are sold through third-party vendors and delivered by ad-syndication networks.
Source: https://threatpost.com/nytimes-scareware-attack-shows-weakness-ad-networks-091509/72290/