Dockerfile

FROM ubuntu:16.04

RUN dpkg --add-architecture i386
RUN apt-get -y update
RUN apt-get -y install libc6 libc6:i386
RUN apt-get -y install -y lib32z1 xinetd

RUN useradd -m ctf
WORKDIR /home/ctf

RUN cp -R /lib* /home/ctf
RUN cp -R /usr/lib* /home/ctf

RUN mkdir /home/ctf/dev
RUN mknod /home/ctf/dev/null c 1 3
RUN mknod /home/ctf/dev/zero c 1 5
RUN mknod /home/ctf/dev/random c 1 8
RUN mknod /home/ctf/dev/urandom c 1 9
RUN chmod 666 /home/ctf/dev/*

RUN mkdir /home/ctf/bin
RUN cp /bin/sh /home/ctf/bin
RUN cp /bin/ls /home/ctf/bin
RUN cp /bin/cat /home/ctf/bin

COPY ./ctf.xinetd /etc/xinetd.d/ctf
COPY ./start.sh /start.sh
RUN echo "Blocked by ctf_xinetd" > /etc/banner_fail

RUN chmod +x /start.sh

COPY ./bin/ /home/ctf/
RUN chown -R root:ctf /home/ctf
RUN chmod -R 750 /home/ctf
RUN chmod 740 /home/ctf/flag

CMD ["/start.sh"]
EXPOSE 9999