> 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/email-attachment-with-multiple-extensions.md).
# Email attachment with multiple extensions
### Synopsis
| Field | Value |
| -------------------- | ------------------------------------------------------------------------------------------- |
| Activation Period | 14 Days |
| Training Period | 30 Days |
| Test Period | N/A (single event) |
| Deduplication Period | 1 Hour 30 Minutes |
| Required Data | Microsoft 365 Emails |
| Detection Modules | Email |
| ATT\&CK Tactic | Execution (TA0002), Stealth (TA0005) |
| ATT\&CK Technique | User Execution: Malicious File (T1204.002), Masquerading: Double File Extension (T1036.007) |
| Severity | Informational |
### Description
The email includes an attachment(s) with two extensions. The first one being an executable extension.
* This may indicate an attempt at masquerading the true file type through the misuse of multiple extensions in the attachment name.
### Attacker's Goals
Trick users into interacting with malicious attachments that seem legitimate.
* Deploy malicious attachments through emails to compromise systems or gain unauthorized access.
### Investigative actions
* Check the file types and investigate the legitimacy of files intended to be sent via email.
* Scrutinize the attachments for any suspicious indications.
* Confirm whether the attachments were successfully delivered to the recipient's mailbox.
* If the attachments were delivered successfully, verify whether the recipient downloaded them.
* Check the email address for any unusual spellings or missing letters.
* Verify the sender's address to confirm its legitimacy.
* Check for previous emails from the sender's address.
### Variations
Email executable attachment with multiple extensions
**Synopsis**
| Field | Value |
| ----------------- | ------------------------------------------------------------------------------------------- |
| ATT\&CK Tactic | Execution (TA0002), Stealth (TA0005) |
| ATT\&CK Technique | User Execution: Malicious File (T1204.002), Masquerading: Double File Extension (T1036.007) |
| Severity | Low |
**Description**
This email includes attachment(s) with multiple extensions, where the last extension is an executable extension.
* This could be a potential attempt to trick the user into executing such file(s).
**Attacker's Goals**
Trick users into interacting with malicious attachments that seem legitimate.
* Deploy malicious attachments through emails to compromise systems or gain unauthorized access.
**Investigative actions**
* Check the file types and investigate the legitimacy of files intended to be sent via email.
* Scrutinize the attachments for any suspicious indications.
* Confirm whether the attachments were successfully delivered to the recipient's mailbox.
* If the attachments were delivered successfully, verify whether the recipient downloaded them.
* Check the email address for any unusual spellings or missing letters.
* Verify the sender's address to confirm its legitimacy.
* Check for previous emails from the sender's address.
Email executable attachment with multiple executable extensions
**Synopsis**
| Field | Value |
| ----------------- | ------------------------------------------------------------------------------------------- |
| ATT\&CK Tactic | Execution (TA0002), Stealth (TA0005) |
| ATT\&CK Technique | User Execution: Malicious File (T1204.002), Masquerading: Double File Extension (T1036.007) |
| Severity | Low |
**Description**
This email includes attachment(s) with multiple executable extensions that are different.
* This could be a potential attempt to trick the user into executing such file(s).
**Attacker's Goals**
Trick users into interacting with malicious attachments that seem legitimate.
* Deploy malicious attachments through emails to compromise systems or gain unauthorized access.
**Investigative actions**
* Check the file types and investigate the legitimacy of files intended to be sent via email.
* Scrutinize the attachments for any suspicious indications.
* Confirm whether the attachments were successfully delivered to the recipient's mailbox.
* If the attachments were delivered successfully, verify whether the recipient downloaded them.
* Check the email address for any unusual spellings or missing letters.
* Verify the sender's address to confirm its legitimacy.
* Check for previous emails from the sender's address.
---
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