Detection: Windows Screen Capture in TEMP folder

Updated Date: 2024-09-24 ID: 00524d1f-a032-46f5-9108-e7d9f01bfb3c Author: Teoderick Contreras, Splunk Type: TTP Product: Splunk Enterprise Security

Description

The following analytic detects the creation of screen capture files by the Braodo stealer malware. This stealer is known to capture screenshots of the victim's desktop as part of its data theft activities. The detection focuses on identifying unusual screen capture activity, especially when images are saved in directories often used by malware, such as temporary or hidden folders. Monitoring for these files helps to quickly identify malicious screen capture attempts, allowing security teams to respond and mitigate potential information exposure before sensitive data is compromised.

Search

1
2|tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_name IN ("screenshot.png", "screenshot.jpg","screenshot.bmp") Filesystem.file_path = "*\\temp\\*" by _time Filesystem.file_name Filesystem.file_path Filesystem.dest Filesystem.file_create_time 
3| `drop_dm_object_name(Filesystem)` 
4| `security_content_ctime(firstTime)` 
5| `security_content_ctime(lastTime)` 
6| `windows_screen_capture_in_temp_folder_filter`

Data Source

No data sources specified for this detection.

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_screen_capture_in_temp_folder_filter	`search *`

windows_screen_capture_in_temp_folder_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
T1113	Screen Capture	Collection

KillChainPhase.EXPLOITAITON

NistCategory.DE_CM

Cis18Value.CIS_10

APT28

APT39

BRONZE BUTLER

Dark Caracal

Dragonfly

FIN7

GOLD SOUTHFIELD

Gamaredon Group

Group5

Magic Hound

MoustachedBouncer

MuddyWater

OilRig

Silence

Volt Typhoon

Winter Vivern

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

To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the Endpoint datamodel in the Processes node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.

Known False Positives

unknown

Associated Analytic Story

Braodo Stealer

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A screen capture named as $file_name$ was created on $dest$.	64	80	80

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	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Microsoft-Windows-Sysmon/Operational`	`XmlWinEventLog`

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: 1