Hackvent 2019: Hidden 3

Challenge

HV19.H3 Hidden Three

Not each quote is compl

Solution

During the Day 11 challenge HV19.11 Frolicsome Santa Jokes API, we decide to do some novice penetration testing on the server whale.hacking-lab.com.

We attempt many things including a port scan with nmap with default settings:

nmap whale.hacking-lab.com

We find some open ports:

PORT     STATE  SERVICE
17/tcp   open   qotd
22/tcp   open   ssh
80/tcp   closed http
443/tcp  closed https
2222/tcp closed EtherNet/IP-1
4444/tcp closed krb524
5555/tcp closed freeciv

Port 17 seems very interesting as it is an uncommon port. We do some research and discover it belongs to the Quote of the Day protocol.

We try to get the quote of the day using this command:

nc whale.hacking-lab.com 17 < /dev/null

Unfortunately, this spits out a single character r which did not make much sense. However, recall the clue that Not each quote is compl. Thus we have to wait until a new letter is given to us! As it turns out a new letter which belongs to the final flag is given to us every hour. As a result, we write a little cron job which logs the date and QOTD result every 15 minutes (to be safe) and decide to check back on it later.

Cron job:

0,15,30,45 * * * * (date;nc whale.hacking-lab.com 17 < /dev/null) >> /home/mo/hackvent/h3.txt

After waiting a full day and checking back our log file looks like this:

Wed Dec 11 22:45:00 AEDT 2019
r
Wed Dec 11 23:00:00 AEDT 2019
_
Wed Dec 11 23:15:00 AEDT 2019
_Wed Dec 11 23:30:01 AEDT 2019
_
Wed Dec 11 23:45:01 AEDT 2019
_
Thu Dec 12 00:00:01 AEDT 2019
D
Thu Dec 12 00:15:01 AEDT 2019
D
Thu Dec 12 00:30:01 AEDT 2019
D
Thu Dec 12 00:45:02 AEDT 2019
D
Thu Dec 12 01:00:01 AEDT 2019
A
Thu Dec 12 01:15:01 AEDT 2019
A
Thu Dec 12 01:30:01 AEDT 2019
A
Thu Dec 12 01:45:01 AEDT 2019
A
Thu Dec 12 02:00:01 AEDT 2019
I
Thu Dec 12 02:15:01 AEDT 2019
I
Thu Dec 12 02:30:01 AEDT 2019
I
Thu Dec 12 02:45:01 AEDT 2019
I
Thu Dec 12 03:00:01 AEDT 2019
L
Thu Dec 12 03:15:01 AEDT 2019
L
Thu Dec 12 03:30:01 AEDT 2019
L
Thu Dec 12 03:45:01 AEDT 2019
L
Thu Dec 12 04:00:01 AEDT 2019
Y
Thu Dec 12 04:15:01 AEDT 2019
Y
Thu Dec 12 04:30:01 AEDT 2019
Y
Thu Dec 12 04:45:01 AEDT 2019
Y
Thu Dec 12 05:00:02 AEDT 2019
_
Thu Dec 12 05:15:01 AEDT 2019
_
Thu Dec 12 05:30:02 AEDT 2019
_
Thu Dec 12 05:45:01 AEDT 2019
_
Thu Dec 12 06:00:01 AEDT 2019
f
Thu Dec 12 06:15:01 AEDT 2019
f
Thu Dec 12 06:30:01 AEDT 2019
f
Thu Dec 12 06:45:01 AEDT 2019
f
Thu Dec 12 07:00:01 AEDT 2019
l
Thu Dec 12 07:15:01 AEDT 2019
l
Thu Dec 12 07:30:01 AEDT 2019
l
Thu Dec 12 07:45:01 AEDT 2019
l
Thu Dec 12 08:00:01 AEDT 2019
4
Thu Dec 12 08:15:01 AEDT 2019
4
Thu Dec 12 08:30:01 AEDT 2019
4
Thu Dec 12 08:45:01 AEDT 2019
4
Thu Dec 12 09:00:01 AEDT 2019
g
Thu Dec 12 09:15:01 AEDT 2019
g
Thu Dec 12 09:30:01 AEDT 2019
g
Thu Dec 12 09:45:01 AEDT 2019
g
Thu Dec 12 10:00:01 AEDT 2019
}
Thu Dec 12 10:15:01 AEDT 2019
}
Thu Dec 12 10:30:01 AEDT 2019
}
Thu Dec 12 10:45:01 AEDT 2019
}
Thu Dec 12 11:00:01 AEDT 2019
H
Thu Dec 12 11:15:01 AEDT 2019
H
Thu Dec 12 11:30:01 AEDT 2019
H
Thu Dec 12 11:45:01 AEDT 2019
H
Thu Dec 12 12:00:01 AEDT 2019
V
Thu Dec 12 12:15:01 AEDT 2019
V
Thu Dec 12 12:30:01 AEDT 2019
V
Thu Dec 12 12:45:01 AEDT 2019
V
Thu Dec 12 13:00:01 AEDT 2019
1
Thu Dec 12 13:15:01 AEDT 2019
1
Thu Dec 12 13:30:01 AEDT 2019
1
Thu Dec 12 13:45:01 AEDT 2019
1
Thu Dec 12 14:00:01 AEDT 2019
9
Thu Dec 12 14:15:01 AEDT 2019
9
Thu Dec 12 14:30:01 AEDT 2019
9
Thu Dec 12 14:45:01 AEDT 2019
9
Thu Dec 12 15:00:01 AEDT 2019
{
Thu Dec 12 15:15:01 AEDT 2019
{
Thu Dec 12 15:30:01 AEDT 2019
{
Thu Dec 12 15:45:01 AEDT 2019
{
Thu Dec 12 16:00:01 AEDT 2019
a
Thu Dec 12 16:15:01 AEDT 2019
a
Thu Dec 12 16:30:01 AEDT 2019
a
Thu Dec 12 16:45:01 AEDT 2019
a
Thu Dec 12 17:00:01 AEDT 2019
n
Thu Dec 12 17:15:01 AEDT 2019
n
Thu Dec 12 17:30:02 AEDT 2019
n
Thu Dec 12 17:45:01 AEDT 2019
n
Thu Dec 12 18:00:01 AEDT 2019
0
Thu Dec 12 18:15:01 AEDT 2019
0
Thu Dec 12 18:30:01 AEDT 2019
0
Thu Dec 12 18:45:01 AEDT 2019
0
Thu Dec 12 19:00:02 AEDT 2019
t
Thu Dec 12 19:15:01 AEDT 2019
t
Thu Dec 12 19:30:01 AEDT 2019
t
Thu Dec 12 19:45:01 AEDT 2019
t
Thu Dec 12 20:00:01 AEDT 2019
h
Thu Dec 12 20:15:01 AEDT 2019
h
Thu Dec 12 20:30:02 AEDT 2019
h
Thu Dec 12 20:45:01 AEDT 2019
h
Thu Dec 12 21:00:01 AEDT 2019
e
Thu Dec 12 21:15:01 AEDT 2019
e
Thu Dec 12 21:30:01 AEDT 2019
e
Thu Dec 12 21:45:01 AEDT 2019
e
Thu Dec 12 22:00:01 AEDT 2019
r
Thu Dec 12 22:15:01 AEDT 2019
r
Thu Dec 12 22:30:02 AEDT 2019
r

Putting all this together gives us our flag!

Flag:

HV19{an0ther_DAILY_fl4g}