SoftwareUpdate Preferences Modification

  1[metadata]
  2creation_date = "2021/01/15"
  3integration = ["endpoint"]
  4maturity = "production"
  5updated_date = "2025/03/18"
  6
  7[rule]
  8author = ["Elastic"]
  9description = """
 10Identifies changes to the SoftwareUpdate preferences using the built-in defaults command. Adversaries may abuse this in
 11an attempt to disable security updates.
 12"""
 13false_positives = ["Authorized SoftwareUpdate Settings Changes"]
 14from = "now-9m"
 15index = ["logs-endpoint.events.*"]
 16language = "eql"
 17license = "Elastic License v2"
 18name = "SoftwareUpdate Preferences Modification"
 19references = ["https://blog.checkpoint.com/2017/07/13/osxdok-refuses-go-away-money/"]
 20risk_score = 47
 21rule_id = "f683dcdf-a018-4801-b066-193d4ae6c8e5"
 22setup = """## Setup
 23
 24This rule requires data coming in from Elastic Defend.
 25
 26### Elastic Defend Integration Setup
 27Elastic Defend is integrated into the Elastic Agent using Fleet. Upon configuration, the integration allows the Elastic Agent to monitor events on your host and send data to the Elastic Security app.
 28
 29#### Prerequisite Requirements:
 30- Fleet is required for Elastic Defend.
 31- To configure Fleet Server refer to the [documentation](https://www.elastic.co/guide/en/fleet/current/fleet-server.html).
 32
 33#### The following steps should be executed in order to add the Elastic Defend integration on a macOS System:
 34- Go to the Kibana home page and click "Add integrations".
 35- In the query bar, search for "Elastic Defend" and select the integration to see more details about it.
 36- Click "Add Elastic Defend".
 37- Configure the integration name and optionally add a description.
 38- Select the type of environment you want to protect, for MacOS it is recommended to select "Traditional Endpoints".
 39- Select a configuration preset. Each preset comes with different default settings for Elastic Agent, you can further customize these later by configuring the Elastic Defend integration policy. [Helper guide](https://www.elastic.co/guide/en/security/current/configure-endpoint-integration-policy.html).
 40- We suggest selecting "Complete EDR (Endpoint Detection and Response)" as a configuration setting, that provides "All events; all preventions"
 41- Enter a name for the agent policy in "New agent policy name". If other agent policies already exist, you can click the "Existing hosts" tab and select an existing policy instead.
 42For more details on Elastic Agent configuration settings, refer to the [helper guide](https://www.elastic.co/guide/en/fleet/current/agent-policy.html).
 43- Click "Save and Continue".
 44- To complete the integration, select "Add Elastic Agent to your hosts" and continue to the next section to install the Elastic Agent on your hosts.
 45For more details on Elastic Defend refer to the [helper guide](https://www.elastic.co/guide/en/security/current/install-endpoint.html).
 46"""
 47severity = "medium"
 48tags = [
 49    "Domain: Endpoint",
 50    "OS: macOS",
 51    "Use Case: Threat Detection",
 52    "Tactic: Defense Evasion",
 53    "Data Source: Elastic Defend",
 54    "Resources: Investigation Guide",
 55]
 56timestamp_override = "event.ingested"
 57type = "eql"
 58
 59query = '''
 60process where host.os.type == "macos" and event.type in ("start", "process_started") and
 61 process.name == "defaults" and
 62 process.args like "write" and process.args like "-bool" and process.args like~ ("com.apple.SoftwareUpdate", "/Library/Preferences/com.apple.SoftwareUpdate.plist") and not process.args like ("TRUE", "true")
 63'''
 64note = """## Triage and analysis
 65
 66> **Disclaimer**:
 67> This investigation guide was created using generative AI technology and has been reviewed to improve its accuracy and relevance. While every effort has been made to ensure its quality, we recommend validating the content and adapting it to suit your specific environment and operational needs.
 68
 69### Investigating SoftwareUpdate Preferences Modification
 70
 71In macOS environments, the SoftwareUpdate preferences manage system updates, crucial for maintaining security. Adversaries may exploit the 'defaults' command to alter these settings, potentially disabling updates to evade defenses. The detection rule identifies such modifications by monitoring specific command executions that attempt to change update preferences without enabling them, signaling potential malicious activity.
 72
 73### Possible investigation steps
 74
 75- Review the process execution details to confirm the presence of the 'defaults' command with arguments attempting to modify SoftwareUpdate preferences, specifically looking for 'write', '-bool', and the targeted preferences file paths.
 76- Check the user account associated with the process execution to determine if it aligns with expected administrative activity or if it might be indicative of unauthorized access.
 77- Investigate the host's recent activity for any other suspicious processes or commands that may suggest a broader attempt to impair system defenses or evade detection.
 78- Examine system logs and security alerts around the time of the detected event to identify any correlated activities or anomalies that could provide additional context or evidence of malicious intent.
 79- Assess the current state of the SoftwareUpdate preferences on the affected host to verify if updates have been disabled or altered, and take corrective actions if necessary.
 80
 81### False positive analysis
 82
 83- System administrators may use the defaults command to configure SoftwareUpdate settings during routine maintenance. To handle this, create exceptions for known administrative scripts or processes that frequently execute these commands.
 84- Automated configuration management tools might alter SoftwareUpdate preferences as part of their standard operations. Identify these tools and exclude their process identifiers from triggering the rule.
 85- Some legitimate applications may require specific update settings and modify preferences accordingly. Monitor and whitelist these applications to prevent unnecessary alerts.
 86- User-initiated changes to update settings for personal preferences can trigger false positives. Educate users on the implications of such changes and consider excluding user-specific processes if they are consistently non-threatening.
 87- During system setup or reconfiguration, defaults commands may be used to establish baseline settings. Temporarily disable the rule or set up a temporary exception during these periods to avoid false alerts.
 88
 89### Response and remediation
 90
 91- Immediately isolate the affected macOS system from the network to prevent potential spread or further unauthorized changes.
 92- Review the process execution logs to confirm the unauthorized use of the 'defaults' command and identify any associated user accounts or processes.
 93- Revert any unauthorized changes to the SoftwareUpdate preferences by resetting them to their default state using the 'defaults' command with appropriate parameters.
 94- Conduct a thorough scan of the affected system for additional signs of compromise, such as malware or unauthorized access attempts, using endpoint security tools.
 95- Change passwords and review permissions for any user accounts involved in the incident to prevent further unauthorized access.
 96- Escalate the incident to the security operations team for further investigation and to determine if additional systems may be affected.
 97- Implement enhanced monitoring for similar command executions across the network to detect and respond to future attempts promptly."""
 98
 99
100[[rule.threat]]
101framework = "MITRE ATT&CK"
102[[rule.threat.technique]]
103id = "T1562"
104name = "Impair Defenses"
105reference = "https://attack.mitre.org/techniques/T1562/"
106[[rule.threat.technique.subtechnique]]
107id = "T1562.001"
108name = "Disable or Modify Tools"
109reference = "https://attack.mitre.org/techniques/T1562/001/"
110
111
112
113[rule.threat.tactic]
114id = "TA0005"
115name = "Defense Evasion"
116reference = "https://attack.mitre.org/tactics/TA0005/"