IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
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User or Group Creation/Modification

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User or Group Creation/Modification

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This rule leverages the auditd_manager integration to detect user or group creation or modification events on Linux systems. Threat actors may attempt to create or modify users or groups to establish persistence on the system.

Rule type: eql

Rule indices:

  • auditbeat-*
  • logs-auditd_manager.auditd-*

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

  • Domain: Endpoint
  • OS: Linux
  • Use Case: Threat Detection
  • Tactic: Persistence
  • Data Source: Auditd Manager

Version: 2

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Setup

This rule requires data coming in from Auditd Manager.

Auditd Manager Integration Setup

The Auditd Manager Integration receives audit events from the Linux Audit Framework which is a part of the Linux kernel. Auditd Manager provides a user-friendly interface and automation capabilities for configuring and monitoring system auditing through the auditd daemon. With auditd_manager, administrators can easily define audit rules, track system events, and generate comprehensive audit reports, improving overall security and compliance in the system.

The following steps should be executed in order to add the Elastic Agent System integration "auditd_manager" on a Linux System:

  • Go to the Kibana home page and click “Add integrations”.
  • In the query bar, search for “Auditd Manager” and select the integration to see more details about it.
  • Click “Add Auditd Manager”.
  • Configure the integration name and optionally add a description.
  • Review optional and advanced settings accordingly.
  • Add the newly installed “auditd manager” to an existing or a new agent policy, and deploy the agent on a Linux system from which auditd log files are desirable.
  • Click “Save and Continue”.
  • For more details on the integration refer to the helper guide.

Rule Specific Setup Note

Auditd Manager subscribes to the kernel and receives events as they occur without any additional configuration. However, if more advanced configuration is required to detect specific behavior, audit rules can be added to the integration in either the "audit rules" configuration box or the "auditd rule files" box by specifying a file to read the audit rules from. For this detection rule to trigger, the following additional audit rules are required to be added to the integration:

-w /usr/sbin/groupadd -p x -k group_modification
-w /sbin/groupadd -p x -k group_modification
-w /usr/sbin/groupmod -p x -k group_modification
-w /sbin/groupmod -p x -k group_modification
-w /usr/sbin/addgroup -p x -k group_modification
-w /sbin/addgroup -p x -k group_modification
-w /usr/sbin/usermod -p x -k user_modification
-w /sbin/usermod -p x -k user_modification
-w /usr/sbin/userdel -p x -k user_modification
-w /sbin/userdel -p x -k user_modification
-w /usr/sbin/useradd -p x -k user_modification
-w /sbin/useradd -p x -k user_modification
-w /usr/sbin/adduser -p x -k user_modification
-w /sbin/adduser -p x -k user_modification

Rule query

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iam where host.os.type == "linux" and event.type in ("creation", "change") and auditd.result == "success" and
event.action in ("changed-password", "added-user-account", "added-group-account-to")

Framework: MITRE ATT&CKTM

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