A modified version of the Christchurch shooter manifesto circulating online includes a payload that overwrites the master boot record in Windows to show a custom message upon system reboot. Researchers at network protection company Blue Hexagon discovered a file that pretends to be the original 74-page manifesto of the shooter. They feel this document is being distributed as a vigilante attack against those who want to download the original document and to halt its spread. The modified document is also shorter than the original, which contains a subset of the pages, not the entire document.
Source: https://www.bleepingcomputer.com/news/security/vigilantes-counter-christchurch-manifesto-with-weaponized-version/