Microsoft 365 Teams Custom Application Interaction Allowed

Identifies when custom applications are allowed in Microsoft Teams. If an organization requires applications other than those available in the Teams app store, custom applications can be developed as packages and uploaded. An adversary may abuse this behavior to establish persistence in an environment.

Elastic rule (View on GitHub)

 1[metadata]
 2creation_date = "2020/11/30"
 3integration = ["o365"]
 4maturity = "production"
 5min_stack_comments = "Breaking change at 8.8.0 for Microsoft 365 Integration."
 6min_stack_version = "8.8.0"
 7updated_date = "2024/04/02"
 8
 9[rule]
10author = ["Elastic"]
11description = """
12Identifies when custom applications are allowed in Microsoft Teams. If an organization requires applications other than
13those available in the Teams app store, custom applications can be developed as packages and uploaded. An adversary may
14abuse this behavior to establish persistence in an environment.
15"""
16false_positives = [
17    """
18    Custom applications may be allowed by a system or network administrator. Verify that the configuration change was
19    expected. Exceptions can be added to this rule to filter expected behavior.
20    """,
21]
22from = "now-30m"
23index = ["filebeat-*", "logs-o365*"]
24language = "kuery"
25license = "Elastic License v2"
26name = "Microsoft 365 Teams Custom Application Interaction Allowed"
27note = """## Setup
28
29The Office 365 Logs Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule."""
30references = ["https://docs.microsoft.com/en-us/microsoftteams/platform/concepts/deploy-and-publish/apps-upload"]
31risk_score = 47
32rule_id = "bbd1a775-8267-41fa-9232-20e5582596ac"
33severity = "medium"
34tags = [
35    "Domain: Cloud",
36    "Data Source: Microsoft 365",
37    "Use Case: Configuration Audit",
38    "Tactic: Persistence",
39]
40timestamp_override = "event.ingested"
41type = "query"
42
43query = '''
44event.dataset:o365.audit and event.provider:MicrosoftTeams and
45event.category:web and event.action:TeamsTenantSettingChanged and
46o365.audit.Name:"Allow sideloading and interaction of custom apps" and
47o365.audit.NewValue:True and event.outcome:success
48'''
49
50
51[[rule.threat]]
52framework = "MITRE ATT&CK"
53
54[rule.threat.tactic]
55id = "TA0003"
56name = "Persistence"
57reference = "https://attack.mitre.org/tactics/TA0003/"

Setup

The Office 365 Logs Fleet integration, Filebeat module, or similarly structured data is required to be compatible with this rule.

References

Related rules

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