> 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/sudden-spike-in-outbound-email-volume.md).

# Sudden spike in outbound email volume

### Synopsis

| Field                | Value                                                              |
| -------------------- | ------------------------------------------------------------------ |
| Activation Period    | 14 Days                                                            |
| Training Period      | 30 Days                                                            |
| Test Period          | 1 Hour                                                             |
| Deduplication Period | 2 Hours                                                            |
| Required Data        | Microsoft 365 Emails                                               |
| Detection Modules    | Email                                                              |
| ATT\&CK Tactic       | Execution (TA0002), Credential Access (TA0006)                     |
| ATT\&CK Technique    | User Execution (T1204), Brute Force: Password Cracking (T1110.002) |
| Severity             | Informational                                                      |

### Description

Unusual amount of emails sent by an internal sender to one or more external recipients within a short timeframe.

### Attacker's Goals

* Extracting valuable information outside the company.
* Bypass Data Loss Prevention (DLP) by splitting data across multiple emails.

### Investigative actions

* Check the content of the email that was sent.
* Review the external recipient address and assess its reputation.
* Review past emails sent from this mailbox for any suspicious activity.
* Check for unusual emails sent to this recipient's address.
* Monitor further action taken, such as accessing to private keys, API tokens and sensitive data.

### Variations

<details>

<summary>Sudden spike in outbound emails sent to external recipients</summary>

**Synopsis**

| Field             | Value                                                              |
| ----------------- | ------------------------------------------------------------------ |
| ATT\&CK Tactic    | Execution (TA0002), Credential Access (TA0006)                     |
| ATT\&CK Technique | User Execution (T1204), Brute Force: Password Cracking (T1110.002) |
| Severity          | Informational                                                      |

**Description**

Unusual amount of emails sent by an internal sender to one or more external recipients within a short timeframe.

**Attacker's Goals**

* Extracting valuable information outside the company.
* Bypass Data Loss Prevention (DLP) by splitting data across multiple emails.

**Investigative actions**

* Check the content of the email that was sent.
* Review the external recipient address and assess its reputation.
* Review past emails sent from this mailbox for any suspicious activity.
* Check for unusual emails sent to this recipient's address.
* Monitor further action taken, such as accessing to private keys, API tokens and sensitive data.

</details>

<details>

<summary>Sudden spike in outbound emails sent to internal recipients</summary>

**Synopsis**

| Field             | Value                                                              |
| ----------------- | ------------------------------------------------------------------ |
| ATT\&CK Tactic    | Execution (TA0002), Credential Access (TA0006)                     |
| ATT\&CK Technique | User Execution (T1204), Brute Force: Password Cracking (T1110.002) |
| Severity          | Informational                                                      |

**Description**

Unusual amount of emails sent by an internal sender to one or more external recipients within a short timeframe.

**Attacker's Goals**

* Extracting valuable information outside the company.
* Bypass Data Loss Prevention (DLP) by splitting data across multiple emails.

**Investigative actions**

* Check the content of the email that was sent.
* Review the external recipient address and assess its reputation.
* Review past emails sent from this mailbox for any suspicious activity.
* Check for unusual emails sent to this recipient's address.
* Monitor further action taken, such as accessing to private keys, API tokens and sensitive data.

</details>


---

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