What is Mimikatz?

Mimikatz is a tool that can be used to display cached credentials of a computer running the Microsoft Windows operating system by exploiting vulnerabilities. The software is freely available and can be downloaded from GitHub in a 32-bit or 64-bit version.

What is Mimikatz?

Mimikatz is a tool that developer Benjamin Delpy originally intended to expose vulnerabilities in the Windows operating system’s management of cached credentials. The software is freely available and can be downloaded from GitHub in a 32-bit or 64-bit version. The first version, written in C, dates back to 2007, while the current version 2.2.0 is from 2019.

With the help of the tool, passwords in plain text or password hashes can be read from the memory of a Windows client. Login data of highly privileged accounts of domain admins, Kerberos tickets, or golden tickets can also be exported, retrieved, or generated via Mimikatz. Methods used by the software include pass-the-hash or pass-the-ticket. The software is used by Windows administrators to check systems for vulnerabilities, by security experts for penetration tests, or by hackers.

Microsoft has repeatedly closed vulnerabilities discovered by Mimikatz in newer Windows versions. However, the software is continuously being developed further and masters the latest methods for determining login data. Many antivirus programs detect the tool and prevent it from being saved or executed.

What is Mimikatz Used For?

Mimikatz is primarily used for retrieving sensitive data from a computer’s memory, such as passwords, hashes, and authentication credentials. It can bypass standard security measures and gain unauthorized access to critical information, making it a significant threat to digital security. Attackers can employ Mimikatz to escalate privileges, impersonate users, and perform lateral movement across a network, potentially leading to data breaches and unauthorized access to sensitive systems. Due to its malicious potential, cybersecurity professionals and organizations must be vigilant in implementing effective defense strategies to detect and prevent Mimikatz-based attacks.

Mimikatz and Credential Theft

Mimikatz is directly related to credential theft as it is a powerful tool specifically designed to steal and manipulate credentials from Windows operating systems. Developed by Benjamin Delpy, Mimikatz has gained notoriety for its ability to exploit vulnerabilities in Windows memory to retrieve sensitive data, such as passwords, hashes, and authentication tokens.

When deployed by attackers, Mimikatz can effectively bypass security measures, gain unauthorized access to user credentials stored in memory, and extract them in plaintext or crackable forms. This means that even if passwords are encrypted or protected, Mimikatz can potentially reveal them in a readable format, compromising the security of user accounts and sensitive systems.

Once an attacker gains access to credentials using Mimikatz, they can use this information for various malicious purposes, including:

• Impersonating Legitimate Users: Attackers can use stolen credentials to impersonate legitimate users, gaining unauthorized access to sensitive data or systems.
• Privilege Escalation: With the right credentials, attackers can escalate privileges, giving them higher levels of access and control over a compromised system or network.
• Lateral Movement: Mimikatz enables attackers to move laterally across a network by using stolen credentials on other machines, potentially expanding the scope of the breach.
• Credential Reuse: If victims use the same credentials for multiple accounts, attackers can exploit this to access other online services or platforms, increasing the potential damage.

The Methods Supported by Mimikatz

The tool is capable of exploiting different Windows vulnerabilities and masters a variety of different methods to extract and display login credentials from a computer’s memory. One of these methods is Pass-the-Hash (PtH). It is a method that uses the password hash rather than the actual password to authenticate a user.

The method exploits a Windows vulnerability based on a static password hash that is always the same from session to session. Other methods that the tool can handle are:

• Pass-the-Ticket
• Over-Pass-the-Hash (Pass-the-Key)
• Kerberos Golden Ticket
• Kerberos Silver Ticket
• Pass-the-Cache

How Mimikatz Works

Mimikatz is a powerful tool used to capture and manipulate credentials from Windows operating systems. It exploits weaknesses in how Windows handles authentication data in memory and has become notorious for its ability to extract sensitive information from the memory of running processes. Here’s a detailed explanation of how Mimikatz works:

Capturing Credentials from Memory

When a user logs into a Windows system, their credentials (username and password) are processed and temporarily stored in memory for authentication purposes. Normally, this sensitive data should be protected and not directly accessible to users or applications. However, Mimikatz can exploit certain security flaws and access this information.

Mimikatz’s primary technique for credential theft is known as “LSASS (Local Security Authority Subsystem Service) Dump.” LSASS is a critical system process responsible for handling authentication requests. Mimikatz injects code into the LSASS process to extract the plaintext credentials from memory. It effectively acts as a “pass-the-ticket” tool, capturing tickets and keys related to the user’s authentication.

Retrieving Password Hashes

In addition to extracting plaintext credentials, Mimikatz can also retrieve password hashes from the LSASS process. Passwords are usually stored in hashed form, which means they are converted into fixed-length values using cryptographic algorithms. Windows uses these password hashes for authentication instead of storing the actual plaintext passwords.

Mimikatz utilizes a technique called “Pass-the-Hash” to retrieve these password hashes from LSASS. With the hashes in hand, attackers can use various techniques to crack them offline, revealing the original plaintext passwords. This presents a significant security risk, as attackers can use these cracked passwords to gain unauthorized access to other systems with the same credentials.

Performing Pass-the-Hash Attacks

Once Mimikatz obtains the password hashes, it enables attackers to perform “Pass-the-Hash” attacks. In a Pass-the-Hash attack, attackers use the captured password hashes to authenticate themselves directly without needing to know the actual plaintext passwords. This way, they can bypass authentication mechanisms, making it difficult for security tools to detect unauthorized access.

With Pass-the-Hash, attackers can escalate privileges, move laterally across the network, and gain access to sensitive resources without needing to crack the password hashes. This technique is particularly dangerous as it leverages the inherent design of Windows authentication protocols and can be challenging to detect using traditional security measures.

The Necessary Steps to Use the Tool and Some Sample Commands

First, Mimikatz must be run in the appropriate 32- or 64-bit version on the Windows machine. For most actions, the software requires administrator rights. After starting the executable program with administrator rights, one gets a console display. These commands can be entered in interactive mode, which is executed in real-time. Commands are for example:

• privilege::debug – for displaying the privileges
• log logfile.log – to record the output in the logfile.log file
• sekurlsa::logonpasswords – output the credentials found in the computer memory in plain text using the “sekursla” module

Notable Features of Mimikatz

Mimikatz is particularly concerning for cybersecurity professionals due to its potential to exploit weak security configurations and vulnerabilities in Windows systems. Here are some notable Mimikatz features:

Support for Various Operating Systems

Mimikatz is designed to work with various versions of the Windows operating system. It is known for its compatibility across different Windows platforms, including Windows 7, Windows 8, Windows 10, and Windows Server editions. This wide range of support makes it a versatile tool for attackers targeting Windows-based environments.

Interacting with LSASS Memory

One of the most powerful capabilities of Mimikatz is its ability to interact with the LSASS (Local Security Authority Subsystem Service) memory. By injecting code into the LSASS process, Mimikatz can access sensitive authentication data stored in memory, such as plaintext credentials and password hashes.

Extraction of Kerberos Tickets

Mimikatz can extract Kerberos tickets from the LSASS memory. Kerberos is the authentication protocol used in Windows domains for secure authentication. By capturing Kerberos tickets, attackers can impersonate legitimate users and gain unauthorized access to various services and resources on the network.

Retrieving Clear Text Passwords

Mimikatz is capable of retrieving clear text passwords from memory. As users log in or authenticate, Windows temporarily stores their plaintext passwords in memory for authentication purposes. Mimikatz can exploit this behavior and extract these clear text passwords, exposing them to attackers.

Impact on Windows Security

Mimikatz’s capabilities pose significant threats to Windows security. Its ability to bypass standard security measures and access sensitive information from memory can lead to serious security breaches. The tool is often used to perform lateral movement within a network, escalate privileges, and gain unauthorized access to critical systems and data.

Given its potent nature, defending against Mimikatz requires a comprehensive security strategy that includes regular updates, strong authentication mechanisms, monitoring for suspicious activities, and proactive security measures to detect and mitigate potential threats posed by this dangerous tool. Organizations must remain vigilant and implement effective security measures to protect against Mimikatz-based attacks and safeguard their valuable data and systems.

High-Profile Hacking Incidents Involving Mimikatz

there have been several high-profile hacking incidents involving the use of Mimikatz or case studies demonstrating its exploitation. Here are some notable examples:

Snowden’s NSA Leaks (2013)

In 2013, Edward Snowden, a former NSA contractor, leaked classified documents to the media, exposing the extensive surveillance activities of the United States National Security Agency (NSA). According to the leaked documents, Mimikatz was one of the tools used by the NSA to gather intelligence and access sensitive data from various sources.

Bangladesh Bank Cyber Heist (2016)

In February 2016, cybercriminals launched a sophisticated attack on Bangladesh Bank, attempting to steal $1 billion. They managed to compromise the bank’s SWIFT messaging system and initiated fraudulent money transfers to accounts in the Philippines. While the attackers used various methods, including phishing and malware, Mimikatz was reportedly used to harvest credentials and escalate privileges within the bank’s network.

Citycomp Data Breach (2019)

In 2019, Citycomp, a German IT service provider, experienced a data breach that exposed customer data from various well-known companies. The attackers allegedly used Mimikatz to obtain credentials and move laterally across the company’s network, leading to the exfiltration of sensitive information.

How to Detect and Mitigate Mimikatz Attacks

Challenges in Detecting Mimikatz Activities

Detecting Mimikatz activities can be challenging due to its ability to operate in memory and evade traditional antivirus and security measures. As Mimikatz does not typically rely on writing files to disk, it leaves minimal traces, making it harder to identify in post-attack investigations. Additionally, its legitimate use in security research and testing tools might cause false positives when detecting its presence.

Strategies to Detect Mimikatz Usage

Behavioral Analysis

Implement behavioral analysis tools that can detect anomalous behavior, such as processes injecting code into LSASS memory or accessing sensitive areas of the system. These tools can flag suspicious activities associated with Mimikatz usage.

Memory Analysis

Conduct memory analysis to identify unusual patterns, such as unauthorized access to LSASS memory or specific API calls related to Mimikatz. Tools like Volatility can assist in memory forensics and uncovering signs of Mimikatz exploitation.

SIEM and Logging

Enable comprehensive logging and integrate logs into a Security Information and Event Management (SIEM) system. Monitor for unusual login activities, failed authentication attempts, and other suspicious events that might indicate Mimikatz usage.

Network Monitoring

Implement network traffic monitoring and analyze patterns indicative of lateral movement or credential harvesting. Unusual network connections or unusual protocols being used could be a sign of Mimikatz-based attacks.

Best Practices for Mitigating Mimikatz Attacks

Regular Patching and Updates

Keep systems, applications, and security software up-to-date to address known vulnerabilities that Mimikatz could exploit.

Least Privilege

Follow the principle of least privilege and restrict user permissions to minimize the potential damage if credentials are compromised.

Multi-Factor Authentication (MFA)

Implement MFA to add an extra layer of security beyond passwords, making it harder for attackers to gain unauthorized access even with stolen credentials.

Strong Password Policies

Enforce strong password policies, including the use of complex and unique passwords, to reduce the success rate of brute force attacks.

Employee Training

Educate employees about phishing and social engineering techniques to reduce the risk of initial access to systems by attackers.

Role of Endpoint Protection and Detection Systems

Endpoint protection and detection systems play a crucial role in detecting and mitigating Mimikatz attacks. These solutions can leverage techniques such as heuristics, behavior analysis, and signature-based detection to identify known and unknown variants of Mimikatz. Some advanced endpoint protection solutions can even spot Mimikatz-like behavior, aiding in early detection and response.

Also, these systems can integrate with centralized management platforms and security operations centers, allowing security teams to respond promptly to potential threats. Continuous monitoring and analysis of endpoint activities can help identify and stop Mimikatz-based attacks before significant damage occurs.

Ethical Use of Mimikatz

Mimikatz can be ethically used in some situations:

Mimikatz as a Security Tool

Ethically, Mimikatz can be used as a security tool by cybersecurity professionals and researchers to test the robustness of Windows security measures. It can be employed in controlled environments to evaluate the effectiveness of endpoint protection, detection, and prevention mechanisms against credential theft techniques. Mimikatz can help identify vulnerabilities in systems and applications, allowing organizations to take proactive measures to strengthen their security posture.

Benefits of Mimikatz in Penetration Testing

Penetration testing, also known as ethical hacking, involves simulating real-world cyber-attacks to identify and fix security weaknesses.

In this context, using Mimikatz can offer significant benefits. By demonstrating how attackers might exploit weaknesses in Windows security, penetration testers can help organizations understand potential risks and implement appropriate countermeasures.

Utilizing Mimikatz in a controlled environment enables the identification of vulnerabilities before malicious actors can exploit them.

Legal and Ethical Considerations for Ethical Hacking

When using Mimikatz or any other hacking tool for ethical purposes, adhering to legal and ethical guidelines is essential. Ethical hackers must obtain explicit authorization from the owners of the systems they intend to test. Performing penetration testing without proper consent is illegal and could lead to severe legal consequences.

Ethical hackers should also adhere to the following principles:

• Scope: Clearly define the scope and objectives of the penetration test, ensuring it only targets the authorized systems.
• Confidentiality: Keep all information discovered during the testing confidential and disclose it only to authorized parties.
• Non-Destructive: Ensure that the penetration testing activities do not cause harm to the systems being tested or disrupt normal operations.
• Reporting: Provide detailed reports to the organization about vulnerabilities found and recommend remediation strategies.
• Compliance: Comply with all relevant laws, regulations, and ethical standards during the penetration testing process.

Mimikatz vs. LaZagne Comparison

Mimikatz and LaZagne are both popular password retrieval tools used in cybersecurity, but they have different focuses and functionalities. Here’s a detailed comparison between Mimikatz and LaZagne:

Mimikatz

Functionality

Mimikatz is a comprehensive post-exploitation tool specifically designed for Windows systems. It is primarily known for its ability to extract and manipulate credentials from Windows operating systems’ memory. Mimikatz can retrieve plaintext passwords, password hashes, and Kerberos tickets from the LSASS process, allowing attackers to escalate privileges and perform lateral movement within a network.

Platform

Mimikatz is targeted exclusively at Windows operating systems. It supports a wide range of Windows versions, making it effective for credential theft across different Windows platforms.

Usage

Malicious actors primarily use Mimikatz for offensive purposes, such as credential theft, privilege escalation, and lateral movement during cyber-attacks. However, it can also serve as a valuable tool for security professionals and researchers for ethical hacking, vulnerability assessments, and testing the robustness of security measures.

LaZagne

Functionality

LaZagne is a versatile open-source password recovery tool designed to retrieve credentials from various applications, browsers, and operating systems. It can recover passwords from popular web browsers, email clients, instant messengers, wireless networks, and more. Unlike Mimikatz, LaZagne is not specifically focused on memory extraction but aims to recover passwords stored in various configurations and applications.

Platform

LaZagne is more platform-agnostic compared to Mimikatz. It supports multiple operating systems, including Windows, macOS, and Linux. This broad compatibility makes it a useful tool for retrieving passwords across different platforms.

Usage

LaZagne is commonly used for security audits, password recovery, and forensic investigations. Security professionals and IT administrators often utilize LaZagne for legitimate and ethical purposes to recover forgotten passwords or assess the security of their systems.

Mimikatz and LaZagne are password retrieval tools with different scopes and functionalities. Mimikatz is specifically tailored for Windows systems and is primarily associated with credential theft and post-exploitation activities. It is often used both by malicious actors and ethical hackers for testing and assessing Windows security.

On the other hand, LaZagne is a cross-platform tool that focuses on password recovery from various applications and platforms. It is typically used for legitimate security purposes, such as auditing and password recovery, and is not limited to Windows systems.

Frequently Asked Questions about Mimikatz

Is Mimikatz malware?

Mimikatz is not inherently malware; it is a legitimate and powerful security tool developed by Benjamin Delpy for security researchers and professionals. However, it can be used by malicious actors as a hacking tool to steal credentials and compromise systems, making it potentially dangerous when used for malicious purposes.

Is Mimikatz legal to use?

Yes, when authorized by the system owner, Mimikatz is legal to use for legitimate security purposes, such as penetration testing, ethical hacking, and research. However, using Mimikatz without proper authorization or for malicious activities is illegal and can result in legal consequences.

How does Mimikatz extract passwords from memory?

Mimikatz extracts passwords from memory by exploiting weaknesses in the way Windows stores authentication credentials. It injects code into the LSASS process, a critical system component responsible for handling authentication, to access sensitive data like plaintext passwords and password hashes stored in memory.

Can Mimikatz be detected by antivirus software?

Mimikatz can be difficult to detect using traditional signature-based antivirus software since it often operates in memory and does not write files to disk. However, advanced endpoint protection and detection systems, behavior-based analysis, and memory forensics tools can help identify Mimikatz activities.

Which operating systems are vulnerable to Mimikatz attacks?

Mimikatz is primarily designed for Windows operating systems and targets various Windows versions, including Windows 7, Windows 8, Windows 10, and Windows Server editions. Other operating systems like macOS and Linux are not directly vulnerable to Mimikatz, but they have their own password retrieval tools with similar capabilities.

What are pass-the-hash attacks, and how are they executed using Mimikatz?

Pass-the-hash is an attack technique in which an attacker uses password hashes obtained from one system to authenticate themselves on another without needing the actual plaintext passwords. Mimikatz can extract password hashes from memory and allow attackers to use those hashes in pass-the-hash attacks.

How can organizations protect themselves from Mimikatz attacks?

Organizations can protect themselves from Mimikatz attacks by following best practices, including regular patching and updates, strong password policies, multi-factor authentication (MFA), network monitoring, and user awareness training. Implementing advanced endpoint protection and detection systems can also help detect and mitigate Mimikatz activities.

Is Mimikatz the only tool for credential theft?

No, Mimikatz is one of the most well-known and potent tools for credential theft, but other similar tools and techniques are used for the same purpose. Cybercriminals may use various password retrieval and hacking tools to steal credentials and compromise systems.

Is Mimikatz open source?

Yes, Mimikatz is an open-source tool. Benjamin Delpy, the original developer, released the source code on GitHub, allowing the cybersecurity community to review, use, and contribute to its development. However, as an open-source tool, its usage must still adhere to legal and ethical guidelines.

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Mimikatz represents a double-edged tool in the cybersecurity landscape. Originally designed for legitimate purposes, its powerful capabilities have also made it a weapon of choice for cybercriminals. While ethical use aids in security testing and research, its malicious exploitation poses severe threats through credential theft and lateral movement within networks. Vigilance, robust defenses, and adherence to ethical guidelines are imperative in countering Mimikatz’s potential risks and safeguarding digital assets.