The Cerber Ransomware is buried in ads on bad or malicious websites. If you click an infected ad, the ransomware will encrypt all of the data on your drive and demand up to $1,000 to get it back.
According to security firm TrendMicro:
Emergency Flash Player Patch for Adobe Flash
Currently, all servers hosting these malvertisements are now inaccessible. Some reports mentioned that CERBER is being peddled in the Russian underground market as ransomware-as-service (RaaS). This not only proves the suggestion presented by the configuration file’s code above, but also confirms that we will be seeing more of CERBER in the near future.