O365 Suspicious Admin Email Forwarding
Description
This search detects when an admin configured a forwarding rule for multiple mailboxes to the same destination.
- Type: Anomaly
-
Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
- Last Updated: 2020-12-16
- Author: Patrick Bareiss, Splunk
- ID: 7f398cfb-918d-41f4-8db8-2e2474e02c28
Annotations
ATT&CK
Kill Chain Phase
- Actions on Objectives
NIST
- DE.DP
- DE.AE
CIS20
- CIS 16
CVE
Search
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`o365_management_activity` Operation=Set-Mailbox
| spath input=Parameters
| rename Identity AS src_user
| search ForwardingAddress=*
| stats dc(src_user) AS count_src_user earliest(_time) as firstTime latest(_time) as lastTime values(src_user) AS src_user values(user) AS user by ForwardingAddress
| where count_src_user > 1
|`security_content_ctime(firstTime)`
|`security_content_ctime(lastTime)`
|`o365_suspicious_admin_email_forwarding_filter`
Macros
The SPL above uses the following Macros:
o365_suspicious_admin_email_forwarding_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Required fields
List of fields required to use this analytic.
- _time
- Operation
- Parameters
How To Implement
You must install splunk Microsoft Office 365 add-on. This search works with o365:management:activity
Known False Positives
unknown
Associated Analytic Story
RBA
Risk Score | Impact | Confidence | Message |
---|---|---|---|
48.0 | 80 | 60 | User $user$ has configured a forwarding rule for multiple mailboxes to the same destination $ForwardingAddress$ |
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.
Reference
Test Dataset
Replay any dataset to Splunk Enterprise by using our replay.py
tool or the UI.
Alternatively you can replay a dataset into a Splunk Attack Range
source | version: 1