Defence CTF Platform "Defender"

While lately there have been observed the growing popularity of cybersecurity competitions, Attack-Defence CTF — the second most common format — has no training solution, besides participating in such competitions. New participants find it complex to administer a server or run exploits on all other participants which creates an entry barrier to the format). This paper introduces a new training method for Attack-Defence CTF and a corresponding hosting system. The training format is not limited in time, does not require much computational resources, but can scale to accommodate a lot of participants. The system runs virtual machines for participants on-demand, which saves resources of organizers and mitigates the time-limited nature of Attack-Defence CTF. To defend their virtual machine, a participant could submit a new snapshot of their machine to the system. The system then turns the machine off and saves it to the cloud using object-storage (S3). The system runs attacks of each participant automatically, which require running virtual machines of other participants. This removes the burden of automating attacks from participants, which eases competition for beginner players. Skills learned in such training are applicable to Attack-Defence CTF, because exploiting and defending are done in a similar format.