Google Workspace User Group Access Modified to Allow External Access

 1[metadata]
 2creation_date = "2022/08/24"
 3integration = ["google_workspace"]
 4min_stack_comments = "New fields added: required_fields, related_integrations, setup"
 5min_stack_version = "8.4.0"
 6maturity = "deprecated"
 7updated_date = "2023/02/16"
 8deprecation_date = "2023/02/16"
 9
10[rule]
11author = ["Elastic"]
12description = """
13User groups in Google Workspace are created to help manage users permissions and access to various resources and
14applications. The security label is only applied to a group when users within that group are expected to access
15sensitive data and/or resources so administrators add this label to easily manage security groups better. Adversaries
16with administrator access may modify a security group to allow external access from members outside the organization.
17This detection does not capture all modifications to security groups, but only those that could increase the risk
18associated with them.
19"""
20false_positives = [
21    """
22    User group access may be modified by an administrator to allow external access for community purposes. Doing so for
23    a user group whom has access to sensitive information or operational resources should be monitored closely.
24    """,
25]
26from = "now-130m"
27index = ["filebeat-*", "logs-google_workspace*"]
28interval = "10m"
29language = "kuery"
30license = "Elastic License v2"
31name = "Google Workspace User Group Access Modified to Allow External Access"
32note = """## Setup
33
34The Google Workspace Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.
35
36### Important Information Regarding Google Workspace Event Lag Times
37- As per Google's documentation, Google Workspace administrators may observe lag times ranging from minutes up to 3 days between the time of an event's occurrence and the event being visible in the Google Workspace admin/audit logs.
38- This rule is configured to run every 10 minutes with a lookback time of 130 minutes.
39- To reduce the risk of false negatives, consider reducing the interval that the Google Workspace (formerly G Suite) Filebeat module polls Google's reporting API for new events.
40- By default, `var.interval` is set to 2 hours (2h). Consider changing this interval to a lower value, such as 10 minutes (10m).
41- See the following references for further information:
42  - https://support.google.com/a/answer/7061566
43  - https://www.elastic.co/guide/en/beats/filebeat/current/filebeat-module-google_workspace.html"""
44references = ["https://support.google.com/a/answer/9468710?hl=en"]
45risk_score = 47
46rule_id = "9cf7a0ae-2404-11ed-ae7d-f661ea17fbce"
47severity = "medium"
48tags = [
49    "Elastic",
50    "Cloud",
51    "Google Workspace",
52    "Continuous Monitoring",
53    "SecOps",
54    "Identity and Access",
55    "Persistence",
56]
57timestamp_override = "event.ingested"
58type = "query"
59
60query = '''
61event.dataset:"google_workspace.admin" and event.action:"CHANGE_GROUP_SETTING" and event.category:"iam"
62    and ((google_workspace.admin.setting.name:"ALLOW_EXTERNAL_MEMBERS" and google_workspace.admin.new_value:"true")
63        or (google_workspace.admin.setting.name:"WHO_CAN_JOIN" and not (google_workspace.admin.new_value:"INVITED_CAN_JOIN"
64            or google_workspace.admin.new_value:"CAN_REQUEST_TO_JOIN")))
65'''
66
67
68[[rule.threat]]
69framework = "MITRE ATT&CK"
70[[rule.threat.technique]]
71id = "T1098"
72name = "Account Manipulation"
73reference = "https://attack.mitre.org/techniques/T1098/"
74[[rule.threat.technique.subtechnique]]
75id = "T1098.003"
76name = "Additional Cloud Roles"
77reference = "https://attack.mitre.org/techniques/T1098/003/"
78
79
80
81[rule.threat.tactic]
82id = "TA0003"
83name = "Persistence"
84reference = "https://attack.mitre.org/tactics/TA0003/"