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Attempts to Brute Force an Okta User Account

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Attempts to Brute Force an Okta User Account

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Identifies when an Okta user account is locked out 3 times within a 3 hour window. An adversary may attempt a brute force or password spraying attack to obtain unauthorized access to user accounts. The default Okta authentication policy ensures that a user account is locked out after 10 failed authentication attempts.

Rule type: threshold

Rule indices:

  • filebeat-*
  • logs-okta*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-180m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Use Case: Identity and Access Audit
  • Tactic: Credential Access
  • Data Source: Okta

Version: 210

Rule authors:

  • Elastic
  • @BenB196
  • Austin Songer

Rule license: Elastic License v2

Investigation guide

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Triage and analysis

Investigating Attempts to Brute Force an Okta User Account

Brute force attacks aim to guess user credentials through exhaustive trial-and-error attempts. In this context, Okta accounts are targeted.

This rule fires when an Okta user account has been locked out 3 times within a 3-hour window. This could indicate an attempted brute force or password spraying attack to gain unauthorized access to the user account. Okta’s default authentication policy locks a user account after 10 failed authentication attempts.

Possible investigation steps:

  • Identify the actor related to the alert by reviewing okta.actor.alternate_id field in the alert. This should give the username of the account being targeted.
  • Review the okta.event_type field to understand the nature of the events that led to the account lockout.
  • Check the okta.severity and okta.display_message fields for more context around the lockout events.
  • Look for correlation of events from the same IP address. Multiple lockouts from the same IP address might indicate a single source for the attack.
  • If the IP is not familiar, investigate it. The IP could be a proxy, VPN, Tor node, cloud datacenter, or a legitimate IP turned malicious.
  • Determine if the lockout events occurred during the user’s regular activity hours. Unusual timing may indicate malicious activity.
  • Examine the authentication methods used during the lockout events by checking the okta.authentication_context.credential_type field.

False positive analysis:

  • Determine whether the account owner or an internal user made repeated mistakes in entering their credentials, leading to the account lockout.
  • Ensure there are no known network or application issues that might cause these events.

Response and remediation:

  • Alert the user and your IT department immediately.
  • If unauthorized access is confirmed, initiate your incident response process.
  • Investigate the source of the attack. If a specific machine or network is compromised, additional steps may need to be taken to address the issue.
  • Require the affected user to change their password.
  • If the attack is ongoing, consider blocking the IP address initiating the brute force attack.
  • Implement account lockout policies to limit the impact of brute force attacks.
  • Encourage users to use complex, unique passwords and consider implementing multi-factor authentication.
  • Check if the compromised account was used to access or alter any sensitive data or systems.

Setup

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The Okta Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

Rule query

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event.dataset:okta.system and event.action:user.account.lock

Framework: MITRE ATT&CKTM

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