This module exploits a shell command injection in the way "delegates"
(commands for converting files) are processed in ImageMagick versions
<= 7.0.1-0 and <= 6.9.3-9 (legacy).
Since ImageMagick uses file magic to detect file format, you can create
a .png (for example) which is actually a crafted SVG (for example) that
triggers the command injection.
Tested on Linux, BSD, and OS X. You'll want to choose your payload
carefully due to portability concerns. Use cmd/unix/generic if need be.