Microsoft 365 Teams External Access Enabled
editMicrosoft 365 Teams External Access Enabled
editIdentifies when external access is enabled in Microsoft Teams. External access lets Teams and Skype for Business users communicate with other users that are outside their organization. An adversary may enable external access or add an allowed domain to exfiltrate data or maintain persistence in an environment.
Rule type: query
Rule indices:
- filebeat-*
- logs-o365*
Severity: medium
Risk score: 47
Runs every: 5 minutes
Searches indices from: now-30m (Date Math format, see also Additional look-back time)
Maximum alerts per execution: 100
References:
Tags:
- Elastic
- Cloud
- Microsoft 365
- Continuous Monitoring
- SecOps
- Configuration Audit
Version: 2 (version history)
Added (Elastic Stack release): 7.11.0
Last modified (Elastic Stack release): 7.11.2
Rule authors: Elastic
Rule license: Elastic License
Potential false positives
editTeams external access may be enabled by a system or network administrator. Verify that the configuration change was expected. Exceptions can be added to this rule to filter expected behavior.
Investigation guide
editThe Microsoft 365 Fleet integration or Filebeat module must be enabled to use this rule.
Rule query
editevent.dataset:o365.audit and event.provider:(SkypeForBusiness or MicrosoftTeams) and event.category:web and event.action:"Set- CsTenantFederationConfiguration" and o365.audit.Parameters.AllowFederatedUsers:True and event.outcome:success
Threat mapping
editFramework: MITRE ATT&CKTM
-
Tactic:
- Name: Persistence
- ID: TA0003
- Reference URL: https://attack.mitre.org/tactics/TA0003/
-
Technique:
- Name: Account Manipulation
- ID: T1098
- Reference URL: https://attack.mitre.org/techniques/T1098/
Rule version history
edit- Version 2 (7.11.2 release)
-
- Formatting only