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.

Rule type: query

Rule indices:

filebeat-*
logs-o365*

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-30m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

https://docs.microsoft.com/en-us/microsoftteams/platform/concepts/deploy-and-publish/apps-upload

Tags:

Elastic
Cloud
Microsoft 365
Continuous Monitoring
SecOps
Configuration Audit
Persistence

Version: 8

Rule authors:

Elastic

Rule license: Elastic License v2

Investigation guide

edit

## Setup

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

Rule query

edit

event.dataset:o365.audit and event.provider:MicrosoftTeams and
event.category:web and event.action:TeamsTenantSettingChanged and
o365.audit.Name:"Allow sideloading and interaction of custom apps" and
o365.audit.NewValue:True and event.outcome:success

Framework: MITRE ATT&CK^TM

Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/

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