The [Windigo](https://attack.mitre.org/groups/G0124) group has been operating since at least 2011, compromising thousands of Linux and Unix servers using the [Ebury](https://attack.mitre.org/software/S0377) SSH backdoor to create a spam botnet. Despite law enforcement intervention against the creators, [Windigo](https://attack.mitre.org/groups/G0124) operators continued updating [Ebury](https://attack.mitre.org/software/S0377) through 2019.(Citation: ESET Windigo Mar 2014)(Citation: CERN Windigo June 2019)