> 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/possible-phishing-attack-via-microsoft-teams.md).

# Possible phishing attack via Microsoft Teams

### Synopsis

| Field                | Value                                                                                                                                                                                                                                |
| -------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| Activation Period    | 14 Days                                                                                                                                                                                                                              |
| Training Period      | 30 Days                                                                                                                                                                                                                              |
| Test Period          | 5 Hours                                                                                                                                                                                                                              |
| Deduplication Period | 1 Day                                                                                                                                                                                                                                |
| Required Data        | <p>Requires all of the following:<br>AzureAD Audit Log<br>Microsoft Graph Logs<br>Office 365 Audit<br>Okta<br>Palo Alto Networks Global Protect OR Third-Party VPNs<br>XDR Agent<br>XDR Agent with eXtended Threat Hunting (XTH)</p> |
| Detection Modules    | Identity Threat Module                                                                                                                                                                                                               |
| Detector Tags        | Microsoft Teams                                                                                                                                                                                                                      |
| ATT\&CK Tactic       | Initial Access (TA0001)                                                                                                                                                                                                              |
| ATT\&CK Technique    | Phishing (T1566)                                                                                                                                                                                                                     |
| Severity             | Low                                                                                                                                                                                                                                  |

### Description

An external tenant is possibly attempting a phishing attack via Microsoft Teams.

### Attacker's Goals

Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.

### Investigative actions

* Verify the suspicious sign-in activity to validate the legitimacy of the suspicious login.
* Review Teams chat logs and meeting invites for interactions with external tenants, focusing on unusual file sharing or unsolicited links.
* Hunt for known phishing indicators (suspicious domains, URL patterns, or IPs) in the Teams messages and linked content.
* Evaluate the external tenant reputation.
* Check for anomalous MS Teams actions like suspicious application installation, message extraction, policy changes or internal spear phishing attempts linked to the user post-login.
* Follow further actions done by the account.

### Variations

<details>

<summary>Potential phishing attack with post compromise stages had been detected</summary>

**Synopsis**

| Field             | Value                   |
| ----------------- | ----------------------- |
| ATT\&CK Tactic    | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566)        |
| Severity          | High                    |

**Description**

Suspicious Microsoft Teams phishing activity detected across multiple indicators, the activities have strong indications of a malicious login and post compromise actions.

**Attacker's Goals**

Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.

**Investigative actions**

* Verify the suspicious sign-in activity to validate the legitimacy of the suspicious login.
* Review Teams chat logs and meeting invites for interactions with external tenants, focusing on unusual file sharing or unsolicited links.
* Hunt for known phishing indicators (suspicious domains, URL patterns, or IPs) in the Teams messages and linked content.
* Evaluate the external tenant reputation.
* Check for anomalous MS Teams actions like suspicious application installation, message extraction, policy changes or internal spear phishing attempts linked to the user post-login.
* Follow further actions done by the account.

</details>

<details>

<summary>Potential phishing attack via Microsoft Teams has been detected</summary>

**Synopsis**

| Field             | Value                   |
| ----------------- | ----------------------- |
| ATT\&CK Tactic    | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566)        |
| Severity          | Medium                  |

**Description**

Suspicious Microsoft Teams phishing activity detected across multiple indicators, the activities have strong indications of a malicious login.

**Attacker's Goals**

Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.

**Investigative actions**

* Verify the suspicious sign-in activity to validate the legitimacy of the suspicious login.
* Review Teams chat logs and meeting invites for interactions with external tenants, focusing on unusual file sharing or unsolicited links.
* Hunt for known phishing indicators (suspicious domains, URL patterns, or IPs) in the Teams messages and linked content.
* Evaluate the external tenant reputation.
* Check for anomalous MS Teams actions like suspicious application installation, message extraction, policy changes or internal spear phishing attempts linked to the user post-login.
* Follow further actions done by the account.

</details>

<details>

<summary>Potential phishing attack with post compromise activities in Microsoft Teams has been detected</summary>

**Synopsis**

| Field             | Value                   |
| ----------------- | ----------------------- |
| ATT\&CK Tactic    | Initial Access (TA0001) |
| ATT\&CK Technique | Phishing (T1566)        |
| Severity          | Medium                  |

**Description**

Suspicious Microsoft Teams phishing activity detected across multiple indicators.

**Attacker's Goals**

Attackers may leverage Microsoft Teams to conduct phishing attacks by exploiting trusted communication channels with users inside the organization.

**Investigative actions**

* Verify the suspicious sign-in activity to validate the legitimacy of the suspicious login.
* Review Teams chat logs and meeting invites for interactions with external tenants, focusing on unusual file sharing or unsolicited links.
* Hunt for known phishing indicators (suspicious domains, URL patterns, or IPs) in the Teams messages and linked content.
* Evaluate the external tenant reputation.
* Check for anomalous MS Teams actions like suspicious application installation, message extraction, policy changes or internal spear phishing attempts linked to the user post-login.
* Follow further actions done by the account.

</details>


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