> For the complete documentation index, see [llms.txt](https://cortex-docs.paloaltonetworks.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cortex-docs.paloaltonetworks.com/analytics-alerts/alerts-by-name/external-user-started-a-microsoft-teams-conversation.md).
# External user started a Microsoft Teams conversation
### Synopsis
| Field | Value |
| -------------------- | ----------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | 1 Hour |
| Deduplication Period | 1 Day |
| Required Data | Office 365 Audit |
| Detection Modules | Identity Threat Module |
| Detector Tags | Microsoft Teams |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
### Description
An external user started a Microsoft Teams conversation with users in the organization.
### Attacker's Goals
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
### Investigative actions
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
### Variations
An external user started multiple conversations in Microsoft Teams with suspicious chat names
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Low |
**Description**
An external user started a Microsoft Teams conversation with users in the organization.
**Attacker's Goals**
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
**Investigative actions**
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
An external user started a conversation in Microsoft Teams with a suspicious user or chat name
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Low |
**Description**
An external user started a Microsoft Teams conversation with users in the organization.
**Attacker's Goals**
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
**Investigative actions**
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
An external user started multiple conversations in Microsoft Teams
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Low |
**Description**
An external user started a Microsoft Teams conversation with users in the organization.
**Attacker's Goals**
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
**Investigative actions**
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
External user started a Microsoft Teams conversation and sent a message
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
**Description**
An external user started a Microsoft Teams conversation with users in the organization.
**Attacker's Goals**
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
**Investigative actions**
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
An external user started conversations in Microsoft Teams with many internal users
**Synopsis**
| Field | Value |
| ----------------- | ----------------------- |
| ATT\&CK Tactic | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566) |
| Severity | Informational |
**Description**
An external user started a Microsoft Teams conversation with users in the organization.
**Attacker's Goals**
Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.
**Investigative actions**
* Confirm that the tenant and user are authorized to start a conversation with users in the organization.
* Verify the content of the conversation and validate that there is no phishing attempt being made.
* Inspect links and URLs that might have been sent in the conversation.
* Check external domain reputation.
* Review past communication from the external user.
* Follow further actions done by the account.
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