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Ringzer0CTF – Linux – Level1


Ringzer0CTF – Linux – Level1
Objective:
Get the flag…… I don’t know what else to put here


Solution:

Find Trinity password

User: morpheus
Password: VNZDDLq2x9qXCzVdABbR1HOtz
ssh challenges.ringzer0team.com port 10089

ok let’s start by connecting via ssh using the provided creds

 morpheus@lxc-sysadmin:~$


lets start by checking the home directory


morpheus@lxc-sysadmin:~$ ls -al
total 20
dr-x------ 2 morpheus morpheus 4096 Oct 17  2018 .
drwxr-xr-x 8 root     root     4096 May 30  2018 ..
lrwxrwxrwx 1 root     root        9 May 30  2018 .bash_history -> /dev/null
-r-x------ 1 morpheus morpheus  220 Aug 31  2015 .bash_logout
-r-x------ 1 morpheus morpheus 3771 Jun  2  2018 .bashrc
lrwxrwxrwx 1 root     root        9 Oct 17  2018 .mysql_history -> /dev/null
-r-x------ 1 morpheus morpheus  655 May 16  2017 .profile


Nothing there…

Lets look at the passwd file to see if trinity exists on the system, so we know if it’s a system account we are trying to gain or if there is something somewhere else


morpheus@lxc-sysadmin:~$ cat /etc/passwd      **********Edited for brevity*********


morpheus:x:1000:1001::/home/morpheus:/bin/bash
trinity:x:1001:1002::/home/trinity:/bin/bash
architect:x:1002:1003::/home/architect:/bin/bash
mysql:x:107:111:MySQL Server,,,:/nonexistent:/bin/false
oracle:x:1003:1004::/home/oracle:/bin/bash
neo:x:1004:1005::/home/neo:/bin/bash
cypher:x:1005:1006::/home/cypher:/bin/bash


ok there is a trinity account with the password stored in the shadow file
let’s see if Morpheus resused his password for root, to see if we can see the shadow file

morpheus@lxc-sysadmin:~$ su
Password:
su: Authentication failure
 

Nope

Ok lets see if trinity is logged in or if there are processes running under her login

Here is the man for PS to see process status

https://ss64.com/bash/ps.html



Let’s start with just ps

morpheus@lxc-sysadmin:~$ ps
  PID TTY          TIME CMD
27052 pts/5    00:00:00 bash
27153 pts/5    00:00:00 ps


That just shows us our running processes let’s see if ps has some switches we can throw to get more data

Lets add -x which gives us more information about the command that associated with process

morpheus@lxc-sysadmin:~$ ps -x
  PID TTY      STAT   TIME COMMAND
25437 ?        SN     0:00 sshd: morpheus@notty
27051 ?        RN     0:00 sshd: morpheus@pts/5
27052 pts/5    SNs    0:00 -bash


Ok but that still only shows the Morpheus processes
Lets add a to get processes from other users

morpheus@lxc-sysadmin:~$ ps -xa
  PID TTY      STAT   TIME COMMAND
    1 ?        Ss     0:04 /sbin/init
   38 ?        Ss     0:35 /lib/systemd/systemd-journald
   73 ?        Ss     0:05 /usr/sbin/cron -f
   75 ?        Ssl    0:08 /usr/sbin/rsyslogd -n
  156 ?        Ss     0:03 /usr/sbin/sshd -D
  159 ?        S      0:27 /bin/sh /root/files/backup.sh -u trinity -p Flag-7e0cfcf090a2fe53c97ea3edd3883d0d
  172 pts/1    Ss+    0:00 /sbin/agetty --noclear --keep-baud pts/1 115200 38400 9600 vt220
  175 ?        Ss+    0:00 /sbin/agetty --noclear --keep-baud console 115200 38400 9600 vt220
  176 pts/0    Ss+    0:00 /sbin/agetty --noclear --keep-baud pts/0 115200 38400 9600 vt220
  178 pts/3    Ss+    0:00 /sbin/agetty --noclear --keep-baud pts/3 115200 38400 9600 vt220
  181 pts/2    Ss+    0:00 /sbin/agetty --noclear --keep-baud pts/2 115200 38400 9600 vt220
  184 ?        Ssl   15:54 /usr/sbin/mysqld
13094 ?        SN     0:00 su neo -c /bin/monitor
13097 ?        SNs    0:00 /bin/monitor
24140 ?        SN     0:00 su cypher -c python /tmp/Gathering.py
24142 ?        SNs    0:00 python /tmp/Gathering.py
24146 ?        SN     0:00 sh -c grep -R password /
24147 ?        SN     0:00 grep -R password /
25420 ?        SNs    0:00 sshd: morpheus [priv]
25437 ?        SN     0:00 sshd: morpheus@notty
27044 ?        SNs    0:00 sshd: morpheus [priv]
27051 ?        SN     0:00 sshd: morpheus@pts/5
27052 pts/5    SNs    0:00 -bash
27202 ?        S      0:00 sleep 10
27204 pts/5    RN+    0:00 ps -xa


Aha there is a backup.sh running with trinity’s user/pass

  159 ?        S      0:27 /bin/sh /root/files/backup.sh -u trinity -p Flag-7e0cfcf090a2fe53c97ea3edd3883d0d





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