kerberos golden ticket attack

Resetting the KRBTGT account password twice in a year helps minimize the chances of compromising the entire domain. Kerberos, initially named after Cerberus, the three-headed dog in Greek mythology, is a network authentication protocol that allows computers and users to prove their identity through a trusted third party. Another tip is to set up an alert that will notify the security team whenever a service principal name (SPN) is created or modified, so they can check that all relevant policies were followed. TGTs are used when requesting Ticket Granting Service (TGS) tickets, which means a forged TGT can get us any TGS ticket - hence it's golden. TGTs are first issued to users as an authentication mechanism after submitting their passwords. In Kerberos environments, referred to as "realms . T1558.002. Kerberos acts as a trusted third party, working with a domain controller (DC) to authenticate clients trying to access services. Gain complete visibility for cloud, multi-cloud, or hybrid environments. The good news: protecting yourself from a Golden Ticket attack is not all that different from protecting yourself any other malware or infiltration attack. Here's the general workflow for a golden ticket attack. The Golden Ticket is the Kerberos authentication token for the KRBTGT account, a special hidden account with the job of encrypting all the authentication tokens for the DC. For more detailed information about the entire Kerberos workflow, visit this Kerberos tutorial site or the RFC for the Kerberos protocol. Detecting Active Directory Kerberos Attacks: Threat Research - Splunk * Inventory unmanaged devices and IoT. After confirming the validity of the TGT, the KDC copies the PAC information into a TGS ticket (2). Learn More, Ransomware Attacks in 2021: A Retrospective. What is a Golden Ticket Attack? Through secured digital identities, enterprises standardize access management and authentication processes to ensure the right users see the right information. In this case, well recognize the attempt to log into a users credentials from a previously unknown IP address in a foreign location. PetitPotam Suspicious Kerberos TGT Request. Lets launch a command prompt under the context of that ticket using themisc::cmdcommand. Cobalt Strike: Advanced Threat Tactics for Penetration Testers. 2005-2023 Splunk Inc. All rights reserved. The Golden Ticket Attack, discovered by security researcher Benjamin Delpy, gives an attacker total and complete access to your entire domain. Active Directory Golden Ticket attacks are very difficult to detect because Golden Tickets look like perfectly valid TGTs. Ultimately, an attacker needs privileged access to create the Golden Ticket in the first place so the more difficult it is for them to steal credentials, the better youre protected. The most insidious part about this attack is you can change the password for the KRBTGT account, but the authentication token is still valid. Retrieved March 29, 2023. Moreover, they can make those tickets valid for as long as they want, even if that violates the organizations time limit policy setting. Being able to detect this kind of attack has historically been difficult, because the adversary is leveraging credentials with the same key your Active Directory uses. Correlate other security systems with login information (e.g., a user has the KRBTGT account password hash and forges Kerberos ticket-granting tickets). [6], Mimikatz's kerberos module can create golden tickets. Zero Trust enforcement never trust, always verify aids in protecting AD and identities, and ensures that users have been continuously verified and authorized before gaining access to any data. Golden Ticket Attacks Explained - QOMPLX AS-REP Roasting. Why NDR? Keep up to date with our weekly digest of articles. On November 9, 2021, Microsoft released patches to address two vulnerabilities that affect Windows Active Directory domain controllers: sAMAccountName Spoofing (CVE-202142278) and Domain Controller Impersonation (CVE-202142287). Monitor for indications of Pass the Ticket being used to move laterally. Book a demo and see the worlds most advanced cybersecurity platform in action. This analytic looks for a process accessing the winlogon.exe system process. The TGT request will be preceded by a computer account name event. This type of attack exploits a weakness in the Kerberos authentication protocol, which is commonly used across global digital workforces. (2020, November 5). The following best practices can help prevent attackers from gaining access. Now it is time to use the Golden Ticket that was loaded into the current session. Golden Ticket Theory; Golden Ticket from Windows ; Golden Ticket from Linux ; OPSEC ; Golden Ticket Theory Golden Ticket from Windows Golden Ticket from Linux OPSEC . However, because the Kerberos ticket is in memory, its possible to connect to a domain controller and gain access to all of the files stored there. Next, the client requests access to a servicerepresented as the service principal name (SPN)by sending the encrypted TGT and the SPN to the KDC. Feedback is welcome! This request will generate a 4768 event with some unusual fields depending on the environment. Although TGT timestamps are not recorded in the Kerberos authentication logs, proper Active Directory security solutions are capable of monitoring them. We then collect and analyze the resulting telemetry to test our detections using Splunk in a lab environment built with the Attack Range. Limit domain admin account permissions to domain controllers and limited servers. With it in hand, a hacker can create a Kerberos ticket to impersonate any AD user they want, including privileged administrators. Our goal is to provide security teams with research they can leverage in their day to day operations and to become the industry standard for SIEM detections. This hunting analytic leverages Kerberos Event 4769. This analytic leverages Kerberos Event 4769 to identify a potential Kerberos Service Ticket request related to a Golden Ticket attack. (Hashing is a one-way algorithm that mathematicallytransforms a given password into a different string. What is Network Detection & Response (NDR)? An endpoint requesting a large number of computer service tickets for different endpoints could represent malicious behavior like lateral movement, malware staging, reconnaissance, etc. A silver ticket is a forged authentication ticket often created when an attacker steals an account password. The KDC automatically trusts a TGT that is encrypted with a KDC key. The Kerberos communication process follows the below steps: A threat actor with a valid KRBTGT account hash can create a forged Golden Ticket using an open-source tool such as Mimikatz. This lab explores an attack on Active Directory Kerberos Authentication. Hashed passwords act as the encryption keys. This Service Ticket can be then used to take control of the domain controller on the final part of the attack. You can rebuild the DC, but that authentication token is still valid. In this blog post, we'll briefly explain what Kerberos and a Golden Ticket are and an attacker's motivation for performing a Golden Ticket attack. The domain controller encrypts the TGS using the target service accounts NTLM password hash and sends it to the user. The Kerberos communication process follows the below steps: The system converts a user's password to a NTLM hash, encrypts a timestamp with the hash and sends it to the Key Distribution Center (KDC) as an authenticator in the authentication ticket (TGT) request. Note that this is a work in progress and does not cover all the existing Kerberos attack techniques. The Golden Ticket Attack, discovered by security researcher Benjamin Delpy, gives an attacker total and complete access to your entire domain. In the scenario that a high-privileged account has an active session on the compromised host, tickets can be dumped and reused to consume services and resources on the network in a similar way to the Pass The Hash NTLM attack. In this section, we present a summary table containing links to the most relevant datasets. If AS is verified then the user gets a Kerberos Ticket Grant Ticket, or TGT, which is proof of authentication. Unusual Number of Kerberos Service Tickets Requested. The Splunk Threat Research Team is an active part of a customers overall defense strategy by enhancing Splunk security offerings with verified research and security content such as use cases, detection searches, and playbooks. maps to the MITRE ATT&CK Credential Access technique under the sub-technique Steal or Forge Kerberos Tickets. To reset the password, you must be a member of both the Domain Admins group and the local Administrators group, or have been delegated the appropriate authority. Once adversaries gain a foothold within an enterprise, they will seek to expand their access by leveraging techniques that facilitate lateral movement and remote code execution. However, if pre-authentication is disabled, this step is skipped and adversaries are able to request a TGT for any domain user. The newly-created TGT is encrypted and signed with a special account on the domain controller known as the Kerberos service (KRBTGT). Enter your search term. The Splunk Threat Research Team (STRT) recommends defenders deploy a comprehensive logging strategy that includes Kerberos events as well as other complementing data sources such as Process and Command-Line, Network Events, local authentication events, application events, etc. Then watch for attempts to log on using that account you may be surprised how many you get. The culmination was last week when Microsoft announced critical vulnerability MS14-068. Before joining Stealthbits - now part of Netwrix, Jeff was a Software Engineer at Wall Street Network, a solutions provider specializing in GIS software and custom SharePoint development. Kerberos Attacks: What You Need to Know - CyberArk Get started in minutes. RC4-HMAC. By obtaining the password hash for this account from the Key Distribution Center (KDC), an attacker is able to compromise every account in Active Directory, giving them unlimited and virtually undetectable access to any system connected to the AD network. The user connects to the application server hosting the service on the appropriate port and presents the TGS. Both categories are disabled by default and provide six types of events generated only on domain controllers when specific actions occur. V for Ventura | How Will Upgrading to macOS 13 Impact Organizations? Make sure you have only the absolute minimum number of Domain Admins, as well as members of other groups that provide logon rights to DCs, such as Print and Server Operators. Despite the names innocent roots, a Golden Ticket attack can be devastating for the targeted enterprise if successfully carried out. Metcalf, S. (2015, August 7). You can be anyone (assuming you have their hash), add any account to any group (including highly privileged groups), and for that matter, do anything you want within Kerberos authentication capabilities. Metcalf, S. (2015, May 03). With the appropriate parameters, Get-ADUser allows adversaries to discover domain accounts with Kerberos Pre Authentication disabled. Jeff holds a Bachelor of Science degree in Information Systems from the University of Delaware. This analytic identifies the execution of the Set-ADAccountControl commandlet with specific parameters. Investigate: An attacker must already have access to the system. Windows Active Directory domain controllers are responsible for handling Kerberos ticket requests, which are used to authenticate users and grant them access to computers and applications. Digital identities allow users to identify themselves electronically and confirm who they are within the scope of an enterprise, software, or service. Thisblog post series covers techniques that attackers can use to find and compromise Active Directory service accounts. Retrieved April 28, 2016. In June 2021, Will Schroeder and Lee Christensen released the whitepaper Certified Pre-Owned: Abusing Active Directory Certificate Services which described scenarios to abuse Microsofts PKI implementation called Active Directory Certificate Services. Retrieved April 13, 2021. (The Windows Event ID 4769 will notify you if a golden ticket is submitted to a DC after the KRBTGT password was reset twice.). A Golden Ticket is a forged Kerberos Ticket-Granting Tickets (TGT) that enables attackers to generate Ticket Granting Service (TGS) tickets for any account in Active Directory and gain unrestricted access to the target resources. First, the client sends user informationincluding the client principal name (CPN)to the KDC. Complete Domain Compromise with a Golden Ticket Attack - Netwrix Silver ticket attacks use this authentication to forge ticket granting service tickets. This service is typically run in each domain controller within an Active Directory (AD) domain. T1558.003. Identity Protection such as Falcon Identity Threat Protection to secure an organizations AD and reduce AD security risks. Rubeus. Please visit our Privacy Statement for additional information, Golden ticket attacks: How they work and how to defend against them. That way, an attacker who manages to get a foothold on an endpoint wont find any privileged credentials there to harvest and use in a Golden Ticket attack. TGTs are first issued to users as an authentication mechanism after submitting their passwords. Golden Ticket attacks take advantage of a vulnerability in the Kerberos authentication protocol, which Microsoft has been using as its default authentication protocol ever since Windows 2000. Kerberos Attacks: Golden Ticket - Daniel Pramatarov When a user wants to access a network serviceto print a file or access a database, for examplethey must first prove their identity and privileges to the service. As part of the sAMAccountName Spoofing and Domain Controller Impersonation exploitation chain, adversaries will need to request a Kerberos Ticket Granting Ticket (TGT) on behalf of the newly created and renamed computer account. It extracts credentials such as user names, passwords, hashes and Kerberos tickets. [7][8], Rubeus can forge a ticket-granting ticket. A large part of these changes involves the exponential increase in digital identities. Smallridge, R. (2018, March 10). What is the KRBTGT account in AD? For those less familiar, a golden ticket is the name of a Kerberos ticket that is manually created by an attacker after gaining access to your environment's encryption "master key". The attack allows an adversary to gain unconstrained access to all services and resources within an Active Directory (AD) domain using a forged Kerberos ticket known as the "Golden Ticket". They include: However its obtained, the KRBTGT password hash is like Willy Wonkas golden ticket. As the name suggests, Set-ADAccountControl is used to modify User Account Control values for an Active Directory domain account. Deply, B., Le Toux, V.. (2016, June 5). Schroeder, W., Warner, J., Nelson, M. (n.d.). If you've already registered, sign in. Make sure its prominent, give it a tempting username and give it membership in some interesting groups. Retrieved December 1, 2017. Before joining Netwrix, Jeff has held multiple roles within Stealthbits - now part of Netwrix, Technical Product Management group since joining the organization in 2010, initially building Stealthbits SharePoint management offerings before shifting focus to the organizations Data Access Governance solution portfolio as a whole. [2], Using a golden ticket, adversaries are then able to request ticket granting service (TGS) tickets, which enable access to specific resources. The service opens the TGS ticket using its NTLM password hash. Credit to author Mauricio Velazco and collaborators Michael Haag, Patrick Bareis, Jose Hernandez, Teoderick Contreras, Eric McGinnis, Rod Soto, and Lou Stella. Kerberos in the Crosshairs: Golden Tickets, Silver Tickets, MITM, and More Retain Access: The ticket can be made valid for up to 10 years, and this type of attack is often not detected. Get-ADUser is part of the Active Directory PowerShell module used to manage Windows Active Directory networks. The Splunk Threat Research team identified this behavior when using the Rubeus tool to monitor for and export Kerberos tickets from memory. In short, Kerberos authentication the default authentication protocol in Active Directory is built upon the assumption that any TGT encrypted with the KRBTGT password hash is legitimate. How Kerberos authentication normally works Under normal circumstances, the Kerberos authentication protocol allows users to authenticate themselves through a trusted third-party authentication service called the Kerberos Key Distribution Center (KDC). Once an attacker obtains a computer certificate by abusing Active Directory Certificate Services in combination with PetitPotam, the next step would be to leverage the certificate for malicious purposes. Golden Ticket attacks have a playful name but they are a serious threat to every Active Directory environment. Monitor and protect your file shares and hybrid NAS. The Golden Ticket attack technique maps to the MITRE ATT&CK Credential Access technique under the sub-technique Steal or Forge Kerberos Tickets. Like this article? If the KDC prompts for authentication, the user is valid. Multiple Disabled Users Failing To Authenticate From Host Using Kerberos. This behavior could represent an adversary abusing the Kerberos protocol to perform a user enumeration attack against an Active Directory environment. Learn how you can monitor Active Directory in real time for active attacks such as Golden Tickets, DCSync and AD database exfiltration. Step 2. Obtain the KRBTGT password hash and domain name and SID. Kerberos in the Crosshairs: Golden Tickets, Silver Tickets, MITM, and More November 24, 2014 It's been a rough year for Microsoft's Kerberos implementation. Below are three ways we can help you begin your journey to reducing data risk at your company: Michael has worked as a sysadmin and software developer for Silicon Valley startups, the US Navy, and everything in between. Windows PowerView Constrained Delegation Discovery. Human-led threat hunting enables 24/7 hunting for unknown and stealthy attacks that utilize stolen credentials and are conducted under the guise of legitimate users. The attacker bypasses the initial step of requesting the TGT from the KDC and directly requests a TGS ticket for a service, such as an administrative share or an important database (3). A Golden Ticket attack is a type of attack in which an adversary gains control over an Active Directory Key Distribution Service Account (KRBTGT), and uses that account to forge valid Kerberos Ticket Granting Tickets (TGTs). Strategic Cyber LLC. Extended detection and response (XDR) solutions collect threat data from tools across an organizations technology stack, which helps expedite the threat hunting and response process. Learn how this type of attack works, associated indicators of compromise, and how best to mitigate and protect against it. See you soon! Also limit the number of servers a domain administrator logs into, and delegate administrative privileges to custom administrator groups. This blog post breaks down the Golden Ticket attack, an identity-based attack that exploits weaknesses in the Kerberos authentication protocol. A member of our team will be in touch shortly. Our customers stop cybercriminals in their tracks while streamlining workflows. The detection calculates the standard deviation for each host and leverages the 3-sigma statistical rule to identify an unusual number of service ticket requests. Steal or Forge Kerberos Tickets: Golden Ticket, Sub-technique T1558.001 Adversaries may abuse Kerberos to validate if a list of users is a domain user or not. When Kerberos is sent a TGT request without prior authentication, it will return different messages depending on if the login credentials are valid or not. XDR solutions can integrate all detection and responses into one command console, enabling an organization to detect a Golden Ticket attack faster with the integrated threat data from across the technology stack. Disabled Kerberos Pre-Authentication Discovery With Get-ADUser. Simplify your procurement process and subscribe to Splunk Cloud via the AWS marketplace, Unlock the secrets of machine data with our new guide. In addition, regularly change your service account passwords, and be sure to pick relatively long passwords to thwart password-guessing and other brute-force attacks. A golden ticket is a forged TGT created with a stolen KDC key. Windows PowerView Unconstrained Delegation Discovery, This analytic utilizes PowerShell Script Block Logging (EventCode=4104). What are Kerberos Golden Ticket Attacks and How to Detect Them Kirsten Gantenbein August 31, 2021 Last Updated on July 11, 2022 When a user wants to access a network serviceto print a file or access a database, for examplethey must first prove their identity and privileges to the service. Adversaries who have the KRBTGT account password hash may forge Kerberos ticket-granting tickets (TGT), also known as a golden ticket. Share information, boost collaboration without sacrificing security. Cloud-delivered, continuous identity assessment solution designed to uncover vulnerabilities in Active Directory and Azure AD. This could be a misconfigured password for a valid user, or it could be an attempt to brute force or guess the password by an outsider. Detect data leaks from employee use of ChatGPT in Reveal(x). Golden Ticket Attack Credential Access Active Directory Credential Theft Kerberos Persistence A golden ticket in Active Directory much like its namesake for Willy Wonka's chocolate factory grants the bearer unlimited access. Monitor for anomalous Kerberos activity, such as malformed or blank fields in Windows logon/logoff events (Event ID 4769, 4768), RC4 encryption within TGTs, and TGS requests without preceding TGT requests. Are you ready to join us? Items to monitor or get alerted on include the following: Unfortunately, the native Windows event logs do not include the TGT timestamps and ferreting out suspicious truly activity in the ocean of events can be a real challenge. Kerberoasting allows an adversary to request Kerberos tickets for domain accounts typically used as service accounts and attempts to crack them offline allowing them to obtain privileged access to the domain. One way of doing this is to request a Kerberos Ticket Granting Ticket using a tool like Rubeus. * Correlate threat intelligence and forensics. The user presents the TGT and requests a Ticket Granting Service (TGS) ticket. Retrieved March 17, 2020. Once an adversary is able to log on interactively or remotely to a DC, they can use Mimikatz to extract the required information using the following commands: This will output the password hash, as well as the domain name and SID: Now the hacker can create Golden Tickets at will. Steal Access: After an attacker has access to the domain controller, they will then steal an NTLM hash of the Active Directory Key Distribution Service Account (KRBTGT). Disabled Kerberos Pre-Authentication Discovery With PowerView. Varonis debuts trailblazing features for securing Salesforce. To prevent Golden Ticket attacks, several traditional security practices are crucial. This analytic looks for a specific combination of the Ticket_Options field based on common Kerberoasting tools. Delegate other admin functions to separate accounts. Kerberos: Golden Tickets - Red Team Notes The KDC trusts the golden ticket and creates a TGS ticket with the fake PAC. The past few years especially have accelerated these changes as organizations adjusted their operations to support a sudden uptick in remote work. Kerberoasting. Obtaining the KRBTGT password hash is the hardest part of the attack because it requires gaining privileged access to a domain controller.

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