Downloaders are malware that can download other malware. Upatre is another famous downloader that is known to download other malware.

We have talked about botnets in Chapter 1, Malware from Fun to Profit. A botnet is a herd of computers that have been compromised and they are controlled by using a C&C server. Botnets can be given a command to download ransomware and other malware. This helps in a mass distribution of ransomware. The Necrus botnet was known to spread scarab and Locky ransomware.