M365 Teams Guest Access Enabled

Last updated 22 days ago on 2025-12-10

Created 5 years ago on 2020-11-20

About

Identifies when guest access is enabled in Microsoft Teams. Guest access in Teams allows people outside the organization to access teams and channels. An adversary may enable guest access to maintain persistence in an environment.

Tags

Domain: CloudData Source: Microsoft 365Use Case: Configuration AuditTactic: PersistenceLanguage: kuery

Severity

medium

Risk Score

MITRE ATT&CK™

Persistence (TA0003)(external, opens in a new tab or window)

↳ Account Manipulation (T1098)(external, opens in a new tab or window)

False Positive Examples

Teams guest 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.

License

Elastic License v2(external, opens in a new tab or window)

Definition

Rule Type: Query (Kibana Query Language)
Integration Pack: Prebuilt Security Detection Rules
Index Patterns: logs-o365.audit-*filebeat-*
Related Integrations: o365(external, opens in a new tab or window)
Query

✄𐘗text code block:
✄𐘗event.dataset:o365.audit and event.provider:(SkypeForBusiness or MicrosoftTeams) and
event.category:web and event.action:"Set-CsTeamsClientConfiguration" and
o365.audit.Parameters.AllowGuestUser:True and event.outcome:success

Install detection rules in Elastic Security

Detect M365 Teams Guest Access Enabled in the Elastic Security detection engine by installing this rule into your Elastic Stack.

To setup this rule, check out the installation guide for Prebuilt Security Detection Rules(external, opens in a new tab or window).