COMMON ATTACK PATTERN ENUMERATION AND CLASSIFICATIONLive MITRE record

CAPEC-509

Kerberoasting

Through the exploitation of how service accounts leverage Kerberos authentication with Service Principal Names (SPNs), the adversary obtains and subsequently cracks the hashed credentials of a service account target to exploit its privileges. The Kerberos authentication protocol centers around a ticketing system which is used to request/grant access to services and to then access the requested services. As an authenticated user, the adversary may request Active Directory and obtain a service ticket with portions encrypted via RC4 with the private key of the authenticated account. By extracting the local ticket and saving it disk, the adversary can brute force the hashed value to reveal the target account credentials.

Abstraction

Detailed

Typical severity

High

Likelihood of attack

Medium

Understand the attack

What is this attack pattern?

Through the exploitation of how service accounts leverage Kerberos authentication with Service Principal Names (SPNs), the adversary obtains and subsequently cracks the hashed credentials of a service account target to exploit its privileges. The Kerberos authentication protocol centers around a ticketing system which is used to request/grant access to services and to then access the requested services. As an authenticated user, the adversary may request Active Directory and obtain a service ticket with portions encrypted via RC4 with the private key of the authenticated account. By extracting the local ticket and saving it disk, the adversary can brute force the hashed value to reveal the target account credentials.

Execution flow

How does the attack proceed, step by step?

1

Explore

Attack step

Scan for user accounts with set SPN values Techniques These can be found via Powershell or LDAP queries, as well as enumerating startup name accounts and other means.

Techniques used

  • These can be found via Powershell or LDAP queries, as well as enumerating startup name accounts and other means.

Attack step

Request service tickets Techniques Using user account's SPN value, request other service tickets from Active Directory

Techniques used

  • Using user account's SPN value, request other service tickets from Active Directory
2

Experiment

Attack step

Extract ticket and save to disk Techniques Certain tools like Mimikatz can extract local tickets and save them to memory/disk.

Techniques used

  • Certain tools like Mimikatz can extract local tickets and save them to memory/disk.
3

Exploit

Attack step

Crack the encrypted ticket to harvest plain text credentials Techniques Leverage a brute force application/script on the hashed value offline until cracked. The shorter the password, the easier it is to crack.

Techniques used

  • Leverage a brute force application/script on the hashed value offline until cracked. The shorter the password, the easier it is to crack.

Requirements

What does the attack require?

Prerequisites

  • The adversary requires access as an authenticated user on the system. This attack pattern relates to elevating privileges.
  • The adversary requires use of a third-party credential harvesting tool (e.g., Mimikatz).
  • The adversary requires a brute force tool.

Skills required

Not stated in the MITRE record.

Resources required

Not stated in the MITRE record.

Impact

What does a successful attack lead to?

Gain Privileges

Affected scopes: Confidentiality

Defence

How is it prevented and mitigated?

1
Monitor system and domain logs for abnormal access.
2
Employ a robust password policy for service accounts. Passwords should be of adequate length and complexity, and they should expire after a period of time.
3
Employ the principle of least privilege: limit service accounts privileges to what is required for functionality and no more.
4
Enable AES Kerberos encryption (or another stronger encryption algorithm), rather than RC4, where possible.

Real world

MITRE example instances

Example instance 1Detail
PowerSploit's Invoke-Kerberoast module can be leveraged to request Ticket Granting Service (TGS) tickets and return crackable ticket hashes. [ REF-585 ] [ REF-586 ]
CAPEC-509: Kerberoasting — DayBreach Saldırı Sözlüğü · DayBreach