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Description

This detection looks for emails that are suspicious because of their sender, domain rareness, or behavior differences. This is an anomaly generated by Splunk User Behavior Analytics (UBA).

  • Type: Anomaly
  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
  • Datamodel: UEBA
  • Last Updated: 2020-07-22
  • Author: Bhavin Patel, Splunk
  • ID: 56e877a6-1455-4479-ad16-0550dc1e33f8

Annotations

ATT&CK
ID Technique Tactic
T1566 Phishing Initial Access
Kill Chain Phase
  • Delivery
NIST
  • PR.IP
CIS20
  • CIS 7
CVE
1
2
3
4
5
6
7
|tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime values(All_UEBA_Events.category) as category from datamodel=UEBA where nodename=All_UEBA_Events.UEBA_Anomalies All_UEBA_Events.UEBA_Anomalies.uba_model = "SuspiciousEmailDetectionModel" by All_UEBA_Events.description All_UEBA_Events.severity All_UEBA_Events.user All_UEBA_Events.uba_event_type All_UEBA_Events.link All_UEBA_Events.signature All_UEBA_Events.url All_UEBA_Events.UEBA_Anomalies.uba_model 
| `drop_dm_object_name(All_UEBA_Events)` 
| `drop_dm_object_name(UEBA_Anomalies)`
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` 
| `suspicious_email___uba_anomaly_filter`

Macros

The SPL above uses the following Macros:

Note that suspicious_email_-_uba_anomaly_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

How To Implement

You must be ingesting data from email logs and have Splunk integrated with UBA. This anomaly is raised by a UBA detection model called “SuspiciousEmailDetectionModel.” Ensure that this model is enabled on your UBA instance.

Known False Positives

This detection model will alert on any sender domain that is seen for the first time. This could be a potential false positive. The next step is to investigate and add the URL to an allow list if you determine that it is a legitimate sender.

Associated Analytic story

RBA

Risk Score Impact Confidence Message
25.0 50 50 tbd

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

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