command_and_control_outlook_home_page.toml

[metadata]
creation_date = "2024/08/01"
integration = ["endpoint", "windows", "m365_defender", "sentinel_one_cloud_funnel"]
maturity = "production"
updated_date = "2024/10/15"
min_stack_version = "8.14.0"
min_stack_comments = "Breaking change at 8.14.0 for the Windows Integration."

[rule]
author = ["Elastic"]
description = """
Identifies modifications in registry keys associated with abuse of the Outlook Home Page functionality for command and
control or persistence.
"""
from = "now-9m"
index = ["winlogbeat-*", "logs-endpoint.events.registry-*", "logs-windows.sysmon_operational-*", "endgame-*", "logs-m365_defender.event-*", "logs-sentinel_one_cloud_funnel.*"]
language = "eql"
license = "Elastic License v2"
name = "Outlook Home Page Registry Modification"
references = [
    "https://cloud.google.com/blog/topics/threat-intelligence/breaking-the-rules-tough-outlook-for-home-page-attacks/",
    "https://github.com/trustedsec/specula"
]
risk_score = 47
rule_id = "ac5a2759-5c34-440a-b0c4-51fe674611d6"
severity = "medium"
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",
]
timestamp_override = "event.ingested"
type = "eql"

query = '''
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*"
'''


[[rule.threat]]
framework = "MITRE ATT&CK"

[rule.threat.tactic]
id = "TA0011"
name = "Command and Control"
reference = "https://attack.mitre.org/tactics/TA0011/"

[[rule.threat]]
framework = "MITRE ATT&CK"
[[rule.threat.technique]]
id = "T1137"
name = "Office Application Startup"
reference = "https://attack.mitre.org/techniques/T1137/"
[[rule.threat.technique.subtechnique]]
id = "T1137.004"
name = "Outlook Home Page"
reference = "https://attack.mitre.org/techniques/T1137/004/"



[rule.threat.tactic]
id = "TA0003"
name = "Persistence"
reference = "https://attack.mitre.org/tactics/TA0003/"