> 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/unusual-attachment-volume-in-outbound-emails.md).
# Unusual attachment volume in outbound emails
### Synopsis
| Field | Value |
| -------------------- | ---------------------------------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | 10 Minutes |
| Deduplication Period | 1 Hour |
| Required Data | Microsoft 365 Emails |
| Detection Modules | Email |
| Detector Tags | Exfiltration |
| ATT\&CK Tactic | Exfiltration (TA0010) |
| ATT\&CK Technique | Exfiltration Over Alternative Protocol (T1048) |
| Severity | Informational |
### Description
Numerous emails with substantial attachments 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
Unusual attachment volume in outbound emails to a single external recipient
**Synopsis**
| Field | Value |
| ----------------- | ---------------------------------------------- |
| ATT\&CK Tactic | Exfiltration (TA0010) |
| ATT\&CK Technique | Exfiltration Over Alternative Protocol (T1048) |
| Severity | Informational |
**Description**
Numerous emails with substantial attachments sent by internal sender to one external recipient 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.
Unusual attachment amount and size in outbound emails
**Synopsis**
| Field | Value |
| ----------------- | ---------------------------------------------- |
| ATT\&CK Tactic | Exfiltration (TA0010) |
| ATT\&CK Technique | Exfiltration Over Alternative Protocol (T1048) |
| Severity | Informational |
**Description**
Numerous emails with substantial attachments 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.
---
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