Outlook Home Page Registry Modification

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Identifies modifications in registry keys associated with abuse of the Outlook Home Page functionality for command and control or persistence.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.registry-*
  • logs-windows.sysmon_operational-*
  • endgame-*
  • logs-m365_defender.event-*
  • logs-sentinel_one_cloud_funnel.*

Severity: medium

Risk score: 47

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Command and Control
  • Tactic: Persistence
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend
  • Data Source: Sysmon
  • Data Source: Microsoft Defender for Endpoint
  • Data Source: SentinelOne

Version: 201

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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registry where host.os.type == "windows" and event.action != "deletion" and registry.value : "URL" and
    registry.path : (
        "HKCU\\*\\SOFTWARE\\Microsoft\\Office\\*\\Outlook\\Webview\\Inbox\\URL",
        "HKEY_USERS\\*\\SOFTWARE\\Microsoft\\Office\\*\\Outlook\\Webview\\Inbox\\URL",
        "HKU\\*\\SOFTWARE\\Microsoft\\Office\\*\\Outlook\\Webview\\Inbox\\URL",
        "\\REGISTRY\\USER\\*\\SOFTWARE\\Microsoft\\Office\\*\\Outlook\\Webview\\Inbox\\URL",
        "USER\\*\\SOFTWARE\\Microsoft\\Office\\*\\Outlook\\Webview\\Inbox\\URL"
    ) and registry.data.strings : "*http*"

Framework: MITRE ATT&CKTM