Description

Due to the operation of the Kerberos service it is possible to extract krbtgs hashes of users within the domain.

Impact

Obtain users hashes.

Recommendation

Configure a logger to alert Kerberoast attacks.

Threat

Unauthorized domain user with valid credentials in the internal network.

Expected Remediation Time

⌚ 120 minutes.

Score

Default score using CVSS 3.1. It may change depending on the context of the src.

Base

• Attack vector: A
• Attack complexity: L
• Privileges required: L
• User interaction: N
• Scope: U
• Confidentiality: L
• Integrity: N
• Availability: N

Temporal

• Exploit code maturity: X
• Remediation level: X
• Report confidence: X

Result

• Vector string: CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N/E:X/RL:X/RC:X
• Score:
• Base: 3.5
• Temporal: 3.5
• Severity:
• Base: Low
• Temporal: Low

Score 4.0

Default score using CVSS 4.0. It may change depending on the context of the src.

Base 4.0

• Attack vector: A
• Attack complexity: L
• Attack Requirements: N
• Privileges required: L
• User interaction: N
• Confidentiality (VC): L
• Integrity (VI): N
• Availability (VA): N
• Confidentiality (SC): N
• Integrity (SI): N
• Availability (SA): N

Threat 4.0

• Exploit maturity: X

Result 4.0

• Vector string: CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X
• Score:
• CVSS-BT: 5.1
• Severity:
• CVSS-BT: Medium

Compliant code

The service should have a defined security group id, that allows a logger to be activated in case of an attack

                Properties:
  GroupDescription: Domain Controllers Security Group
  VpcId: !Ref VPCID
  SecurityGroupIngress:
- IpProtocol: tcp
      Description: Kerberos
      FromPort: 88
      ToPort: 88
      SourceSecurityGroupId: !Ref AdminMembersSG

            

Non compliant code

A Kerberoast service uses the default security group configuration

                Properties:
  GroupDescription: Domain Controllers Security Group
  VpcId: !Ref VPCID
  SecurityGroupIngress:
- IpProtocol: tcp
      Description: Kerberos
      FromPort: 88
      ToPort: 88
      SourceSecurityGroupId: Allow

            

Requirements

• 266.Disable insecure functionalities

Fixes

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