LoFP / teams 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.

Techniques

• T1098

Sample rules

Microsoft 365 Teams External Access Enabled

• source: elastic
• technicques:
  • T1098

Description

Identifies 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.

Detection logic

event.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