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Hack The Box: October

October -

Target enumeration:

OS: Linux


User: 29161ca87aa3d34929dc46efc40c89c0

Root: 6bcb9cff749c9318d2a6e71bbcf30318

Ports / Services / Software versions running

22/tcp open  ssh OpenSSH 6.6.1p1 Ubuntu 2ubuntu2.8 (Ubuntu Linux; protocol 2.0)80/tcp open  http Apache httpd 2.4.7 ((Ubuntu))Vulnerability Exploited:

Weak password on CMS

Privilege escalation:

Buffer overflow on /usr/local/bin/ovrflw

Exploiting the host:



Backend gives us a login page

Username enumeration gives us a user of admin so start burp and bruteforce the password with intruder.

Does not appear to be vulnerable to brute force so revert the box and try a stealthy approach.

Try common passwords such as password, october, admin etc.

Admin:admin gives you access to the CMS

Upload a php shell which will not work so rename it to shell.php5

Click on the public link and you will get a reverse shell

Checking suid files gives you:

The name suggests it is vulnerable to a buffer overflow. The machine has GDB installed but not peda so download the file locally to work on the buffer overflow.

Copy the file to /var/www/html/cms/storage/app/media

And download with wget locally

We will need peda to work on the buffer overflow:

git clone https://github.com/longld/peda.git

echo "source ~/peda/peda.py" >> ~/.gdbinit

Check the security of the file

Strcpy is interesting.

Fuzz the program

Run the program with r

Note the breakpoint

Query the offset

EIP offset is 112

Note the memory addresses on October and find memory address of /bin/sh

It is easier if you break it down in notepad

Bruteforce the memory addresses to bypass NX

After a few minutes you have a root shell so collect your flag