What is Drive-by Web Skimming?

In drive-by web skimming, a threat actor compromises third- or fourth-party code with malware, with the hope that multiple organizations use this code and infect their websites and web applications inadvertently. Modern web applications load an average of over 20 third- and fourth-party scripts as part of the user experience. Compromising one of these third- or fourth-party elements with malicious JavaScript allows an attacker to compromise multiple websites simultaneously.