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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

ATT&CK

ID Technique Tactic
T1114.002 Remote Email Collection Collection
T1114 Email Collection Collection
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
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:

:information_source: 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 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

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

:information_source: 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