Adversaries may buy, lease, or rent a network of compromised systems that can be used during targeting. A botnet is a network of compromised systems that can be instructed to perform coordinated tasks.(Citation: Norton Botnet) Adversaries may purchase a subscription to use an existing botnet from a booter/stresser service. With a botnet at their disposal, adversaries may perform follow-on activity such as large-scale [Phishing](https://attack.mitre.org/techniques/T1566) or Distributed Denial of Service (DDoS).(Citation: Imperva DDoS for Hire)(Citation: Krebs-Anna)(Citation: Krebs-Bazaar)(Citation: Krebs-Booter)