Over the past few months, [sucuri.net's] security operations group have identified and mitigated an increasing number of DDoS attacks tied to extortion attempts from different cyber crime groups, including DD4BC, Armada Collective and a few more unnamed ones. These DDoS extortion attempts [sucuri.net] are starting to exploit smaller websites that may be less able to defend themselves.
[A] ransom email is followed by a small scale DDoS attack that can last from 30 to 60 minutes. After 24 hours, if the ransom is not paid, the attacks increase and can last many hours.