Malvertising

What the technique is

Adversaries may purchase online advertisements that can be abused to distribute malware to victims. Ads can be purchased to plant as well as favorably position artifacts in specific locations online, such as prominently placed within search engine results. These ads may make it more difficult for users to distinguish between actual search results and advertisements. Purchased ads may also target specific audiences using the advertising network’s capabilities, potentially further taking advantage of the trust inherently given to search engines and popular websites. Adversaries may purchase ads and other resources to help distribute artifacts containing malicious code to victims. Purchased ads may attempt to impersonate or spoof well-known brands. For example, these spoofed ads may trick victims into clicking the ad which could then send them to a malicious domain that may be a clone of official websites containing trojanized versions of the advertised software. Adversary’s efforts to create malicious domains and purchase advertisements may also be automated at scale to better resist cleanup efforts. Malvertising may be used to support Drive-by Target and Drive-by Compromise, potentially requiring limited interaction from the user if the ad contains code/exploits that infect the target system's web browser. […]

What MITRE says you would watch

• AN1968

  If infrastructure or patterns in the malicious web content related to malvertising have been previously identified, internet scanning may uncover when an adversary has staged malicious web content. Much of this activity will take place outside the visibility of the target organization, making detection of this behavior difficult. Detection efforts may be focused on other phases of the adversary lifecycle, such as Drive-by Compromise or Exploitation for Client Execution.