> 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/single-ip-accessed-mail-items-of-multiple-users.md).

# Single IP accessed mail items of multiple users

### 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, Email                         |
| Detector Tags        | Extortion                                             |
| ATT\&CK Tactic       | Collection (TA0009)                                   |
| ATT\&CK Technique    | Email Collection: Remote Email Collection (T1114.002) |
| Severity             | Informational                                         |

### Description

A single caller IP accessed Exchange mail items belonging to multiple distinct users within a short time window. This pattern indicates mailbox harvesting from a shared attacker vantage point (VPS or AiTM box).

### Attacker's Goals

An adversary may use a single IP address to access mail items across multiple user accounts, which can aid in the centralized collection and bulk exfiltration of organizational email data.

### Investigative actions

* Pivot on the caller IP across all SaaS audit logs and review every session originated from it.
* For each impacted user, look for fresh OAuth grants, new inbox rules, MFA enrolment changes and anomalous logins.
* Check the IP reputation in SPUR/threat-intel and revoke active sessions for the affected users.

### Variations

<details>

<summary>Single IP accessed mail items of multiple users with suspicious characteristics</summary>

**Synopsis**

| Field             | Value                                                 |
| ----------------- | ----------------------------------------------------- |
| ATT\&CK Tactic    | Collection (TA0009)                                   |
| ATT\&CK Technique | Email Collection: Remote Email Collection (T1114.002) |
| Severity          | Low                                                   |

**Description**

A single caller IP accessed Exchange mail items belonging to multiple distinct users within a short window, and the IP address contributed additional suspicious characteristics (e.g., unmanaged or risky caller IP, anomalous country or ASN for these users).

**Attacker's Goals**

An adversary may use a single IP address to access mail items across multiple user accounts, which can aid in the centralized collection and bulk exfiltration of organizational email data.

**Investigative actions**

* Pivot on the caller IP across all SaaS audit logs and review every session originated from it.
* For each impacted user, look for fresh OAuth grants, new inbox rules, MFA enrolment changes and anomalous logins.
* Check the IP reputation in SPUR/threat-intel and revoke active sessions for the affected users.

</details>


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