Detection: O365 Threat Intelligence Suspicious File Detected

Updated Date: 2024-11-14 ID: 00958c7b-35db-4e7a-ad13-31550a7a7c64 Author: Steven Dick Type: TTP Product: Splunk Enterprise Security

Description

The following analytic identifies when a malicious file is detected within the Microsoft Office 365 ecosystem through the Advanced Threat Protection engine. Attackers may stage and execute malicious files from within the Microsoft Office 365 ecosystem. Any detections from built-in Office 365 capabilities should be monitored and responded to appropriately. Certain premium Office 365 capabilities such as Safe Attachment and Safe Links further enhance these detection and response functions.

Search

1`o365_management_activity` Workload=ThreatIntelligence Operation=AtpDetection 
2| stats values(DetectionMethod) as category  values(FileData.FileName) as file_name values(FileData.FilePath) as file_path values(FileData.FileSize) as file_size values(FileData.MalwareFamily) as signature count, min(_time) as firstTime, max(_time) as lastTime by Id, UserId 
3| rename Id as signature_id, UserId as user 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `o365_threat_intelligence_suspicious_file_detected_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
o365_management_activity	`sourcetype=o365:management:activity`
o365_threat_intelligence_suspicious_file_detected_filter	`search *`

o365_threat_intelligence_suspicious_file_detected_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
T1204.002	Malicious File	Execution
T1204	User Execution	Execution

Installation

DE.CM

CIS 10

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 threat intelligence workload is typically only visible to E3/E5 level customers.

Known False Positives

unknown

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message:

Threat Intelligence workload detected a malicious file [$file_name$] from user $user$

Risk Object	Risk Object Type	Risk Score	Threat Objects
user	user	50	file_name

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: 3