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Description

This search detects the assignment of rights to accesss content from another mailbox. This is usually only assigned to a service account.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2020-12-15
  • Author: Patrick Bareiss, Splunk
  • ID: b25d2973-303e-47c8-bacd-52b61604c6a7

Annotations

ATT&CK
ID Technique Tactic
T1114.002 Remote Email Collection Collection
T1114 Email Collection Collection
Kill Chain Phase
  • Actions on Objectives
NIST
  • DE.DP
  • DE.AE
CIS20
  • CIS 16
CVE 
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`o365_management_activity` Operation=Add-MailboxPermission 
| spath input=Parameters 
| rename User AS src_user, Identity AS dest_user 
| search AccessRights=FullAccess OR AccessRights=SendAs OR AccessRights=SendOnBehalf 
| stats count earliest(_time) as firstTime latest(_time) as lastTime by user src_user dest_user Operation AccessRights 
|`security_content_ctime(firstTime)` 
|`security_content_ctime(lastTime)` 
|`o365_suspicious_rights_delegation_filter`

Macros

The SPL above uses the following Macros:

Note that o365_suspicious_rights_delegation_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required field

  • _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

Service Accounts

Associated Analytic story

RBA

Risk Score Impact Confidence Message
48.0 80 60 User $user$ has delegated suspicious rights $AccessRights$ to user $dest_user$ that allow access to sensitive

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