Nibbles (Linux) Write-up - LinEnum & How to call a bash shell with sudo priv

I've done this box a long time ago while following a TCM's video, but I decided to give it a go again with fresh perspective.

Nmap Scan Result:

Nmap scan report for
Host is up (0.11s latency).
Not shown: 65532 closed tcp ports (conn-refused)
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)
58848/tcp filtered unknown
Service Info: OS: Linux; CPE: cpe:/o:linux:linux_kernel

Let's do web enumeration first.

Visiting the IP, I found the nibbleblog directory which took me to a blog site.

Started the gobuster from the directory:

gobuster dir -u -w /usr/share/wordlists/dirbuster/directory-list-2.3-medium.txt







Version was found in:

Version: v4.0.3

Codename: Coffee Release date: 2014-04-01

Site: Blog: Help & Support: Documentation:


"Unrestricted file upload vulnerability in the My Image plugin in Nibbleblog before 4.0.5 allows remote administrators to execute arbitrary code by uploading a file with an executable extension, then accessing it via a direct request to the file in content/private/plugins/my_image/image.php."

Found admin.php page and attempted login with Username:admin password: nibbles ---> successful

Found a directory where I can upload a reverse shell script.

Uploaded a reverse shell and got the shell back.

can't access tty though.

"bash -i" to make it interactive.

or python3 pty option

By typing sudo -l reveals that /home/nibbler/personal/stuff/ can be ran as root without password

so I have unzipped the file (unzip and removed the current shell file.

Created a new file with vim:

bash -i 

We utilized the Sudo functionality to run a script to call the bash with root privilege.

Running Linux Exploit Suggester

host it on python simplehttp server and download it from the nibble server with

curl -o IP/

We'll try the RationalLove

Get the exploit and upload it again.

We need to compile the c file with gcc -o FILE_NAME Rationallove.c

For some reason, I had to execute it twice to get it work, but it worked!

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