What is a Golden Ticket Attack?
A golden ticket attack is a cyberattack targeting Active Directory (AD). As is responsible for managing identity and access management (IAM) in Windows environments.
A golden ticket attack exploits the Kerberos protocol, which manages the shared secrets used for data encryption and digital signatures in Windows environments. A successful attack provides the attacker with unauthorized and often global access to network resources, data, and systems within the target Windows environment.
How Does a Golden Ticket Attack Work?
A golden ticket attack exploits Active Directory and the Kerberos protocol, which is used for authentication in Active Directory environments. The attack can be carried out via the folowing steps:
- Key Theft: A golden ticket attack relies on the attacker gaining access to the secret key belonging to the Key Distribution Service Account (KRBTGT). This secret key is used to create Ticket Granting Tickets (TGTs), which validate a user’s identity and are used to generate specific tickets granting access to particular services.
- TGT Forgery: Using the stolen private key, the attacker is able to forge their own TGT. This is the “golden ticket” that the attack is named for.
- Authentication: A TGT is used to authenticate a user’s identity to the Ticket Granting Service (TGS). The attacker’s TGT can be used to generate service tickets that allow them access to various services.
A successful golden ticket attack enables an attacker to generate a TGT. Since this ticket looks legitimate, the attacker is able to access any network resources within the Windows environment. Additionally, since the lifetime of a TGT is written into the ticket itself, the golden ticket can be configured to offer long-term access until the attack is discovered and the secret key is changed.
Implications of a Golden Ticket Attack
A golden ticket attack compromises an organization’s IAM system and has significant potential repercussions, including:
- Privilege Escalation: A successful golden ticket attack enables the attacker to produce a TGT with any level of access. This includes the ability to elevate privileges as high as domain administrator.
- Data Breach: The attacker has access to Active Directory and to various network resources through its forged tickets. This allows the attacker to steal sensitive data from the organization.
- Undetectable Access: After the attacker has the Key KRBTGT secret key, the tickets that they generate are indistinguishable from real ones. This makes the attack very difficult to detect.
Protecting Against Golden Ticket Attacks
Some best practices that help to manage the risk and impact of golden ticket attacks include the following:
- Key Rotation: Golden tickets are only valid as long as the stolen key remains the same. Regularly rotating this key reduces the potential lifetime of a golden ticket.
- Network Monitoring: Monitoring the network for anomalous behaviors can help to identify abuse of golden tickets.
- Least Privilege: Granting users only the access that they need for their job makes golden ticket attacks harder to perform.
- Patch Management: Promptly applying updates and patches reduces the risk of a vulnerability that an attacker can exploit to gain Active Directory access.
- Access Management: Multi-factor authentication (MFA) and strong access management make it harder for attackers to gain the access needed in their attacks.
Golden ticket attacks use a stolen Key Distribution Service Account secret key to forge TGTs. With these TGTs, the attacker can gain access to a range of network resources and elevate their privileges on the system.