Detection: O365 Safe Links Detection

Description

The following analytic detects when any Microsoft Safe Links alerting is triggered. This behavior may indicate when user has interacted with a phishing or otherwise malicious link within the Microsoft Office ecosystem.

1`o365_management_activity` Name="*a potentially malicious URL*" Operation=AlertEntityGenerated 
2| fromjson Data 
3| stats count min(_time) as firstTime max(_time) as lastTime values(ObjectId) as url values(od) as desc by AlertId,trc,Operation,Name,ot 
4| rename Name as signature, AlertId as signature_id, trc as user,ot as action 
5| eval action = CASE(action == "Allowed", "allowed", action=="BlockPageOverride", "allowed", true(),"blocked") 
6| `security_content_ctime(firstTime)` 
7| `security_content_ctime(lastTime)` 
8| `o365_safe_links_detection_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name Value
o365_management_activity sourcetype=o365:management:activity
o365_safe_links_detection_filter search *
o365_safe_links_detection_filter is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Annotations

- MITRE ATT&CK
+ Kill Chain Phases
+ NIST
+ CIS
- Threat Actors
ID Technique Tactic
T1566 Phishing Initial Access
T1566.001 Spearphishing Attachment Initial Access
KillChainPhase.DELIVERY
NistCategory.DE_CM
Cis18Value.CIS_10
Axiom
GOLD SOUTHFIELD
INC Ransom
APT-C-36
APT1
APT12
APT19
APT28
APT29
APT30
APT32
APT33
APT37
APT38
APT39
APT41
Ajax Security Team
Andariel
BITTER
BRONZE BUTLER
BlackTech
CURIUM
Cobalt Group
Confucius
DarkHydrus
Darkhotel
Dragonfly
EXOTIC LILY
Elderwood
FIN4
FIN6
FIN7
FIN8
Ferocious Kitten
Gallmaker
Gamaredon Group
Gorgon Group
Higaisa
Inception
IndigoZebra
Kimsuky
Lazarus Group
LazyScripter
Leviathan
Machete
Malteiro
Mofang
Molerats
Moonstone Sleet
MuddyWater
Mustang Panda
Naikon
Nomadic Octopus
OilRig
PLATINUM
Patchwork
RTM
Rancor
RedCurl
Saint Bear
Sandworm Team
SideCopy
Sidewinder
Silence
Star Blizzard
TA2541
TA459
TA505
TA551
The White Company
Threat Group-3390
Tonto Team
Transparent Tribe
Tropic Trooper
WIRTE
Windshift
Winter Vivern
Wizard Spider
admin@338
menuPass

Default Configuration

This detection is configured by default in Splunk Enterprise Security to run with the following settings:

Setting Value
Disabled true
Cron Schedule 0 * * * *
Earliest Time -70m@m
Latest Time -10m@m
Schedule Window auto
Creates Notable Yes
Rule Title %name%
Rule Description %description%
Notable Event Fields user, dest
Creates Risk Event True
This configuration file applies to all detections of type TTP. These detections will use Risk Based Alerting and generate Notable Events.

Implementation

You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events. The Safe Links capability must be configured and is typically only available to E3/E5 level customers.

Known False Positives

Based on Safe Links policies, may vary.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
$user$ triggered a Microsoft Safe Links detection. 40 40 100
The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

References

Detection Testing

Test Type Status Dataset Source Sourcetype
Validation Passing N/A N/A N/A
Unit Passing Dataset o365 o365:management:activity
Integration ✅ Passing Dataset o365 o365:management:activity

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: GitHub | Version: 2