ID | Technique | Tactic |
---|---|---|
T1113 | Screen Capture | Collection |
Detection: Windows Screen Capture Via Powershell
Description
The following analytic detects the execution of a PowerShell script designed to capture screen images on a host. It leverages PowerShell Script Block Logging to identify specific script block text patterns associated with screen capture activities. This behavior is significant as it may indicate an attempt to exfiltrate sensitive information by capturing desktop screenshots. If confirmed malicious, this activity could allow an attacker to gather visual data from the compromised system, potentially leading to data breaches or further exploitation.
Search
1`powershell` EventCode=4104 ScriptBlockText = "*[Drawing.Graphics]::FromImage(*" AND ScriptBlockText = "*New-Object Drawing.Bitmap*" AND ScriptBlockText = "*.CopyFromScreen*"
2| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID
3| `security_content_ctime(firstTime)`
4| `security_content_ctime(lastTime)`
5| `windows_screen_capture_via_powershell_filter`
Data Source
Name | Platform | Sourcetype | Source | Supported App |
---|---|---|---|---|
Powershell Script Block Logging 4104 | Windows | 'xmlwineventlog' |
'XmlWinEventLog:Microsoft-Windows-PowerShell/Operational' |
N/A |
Macros Used
Name | Value |
---|---|
powershell | (source=WinEventLog:Microsoft-Windows-PowerShell/Operational OR source="XmlWinEventLog:Microsoft-Windows-PowerShell/Operational") |
windows_screen_capture_via_powershell_filter | search * |
windows_screen_capture_via_powershell_filter
is an empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.
Annotations
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 |
Implementation
To successfully implement this analytic, you will need to enable PowerShell Script Block Logging on some or all endpoints. Additional setup here https://docs.splunk.com/Documentation/UBA/5.0.4.1/GetDataIn/AddPowerShell#Configure_module_logging_for_PowerShell.
Known False Positives
unknown
Associated Analytic Story
Risk Based Analytics (RBA)
Risk Message | Risk Score | Impact | Confidence |
---|---|---|---|
A PowerShell script was identified possibly performing screen captures on $Computer$. | 49 | 70 | 70 |
References
Detection Testing
Test Type | Status | Dataset | Source | Sourcetype |
---|---|---|---|---|
Validation | ✅ Passing | N/A | N/A | N/A |
Unit | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/Operational |
xmlwineventlog |
Integration | ✅ Passing | Dataset | XmlWinEventLog:Microsoft-Windows-PowerShell/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: 2