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Description

The following analytic identifies a potential PowerShell script that captures screen images on compromised or targeted hosts. This technique was observed in the Winter-Vivern malware, which attempts to capture desktop screens using a PowerShell script and send the images to its C2 server as part of its exfiltration strategy. This TTP serves as a useful indicator that a PowerShell process may be gathering desktop screenshots from a host system, potentially signaling malicious activity.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2023-04-05
  • Author: Teoderick Contreras, Splunk
  • ID: 5e0b1936-8f99-4399-8ee2-9edc5b32e170

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1113 Screen Capture Collection
Kill Chain Phase
  • Exploitation
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


1
2
3
4
5



`powershell` EventCode=4104 ScriptBlockText = "*[Drawing.Graphics]::FromImage(*" AND ScriptBlockText = "*New-Object Drawing.Bitmap*" AND ScriptBlockText = "*.CopyFromScreen*" 
| stats count min(_time) as firstTime max(_time) as lastTime by EventCode ScriptBlockText Computer UserID 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `windows_screen_capture_via_powershell_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_screen_capture_via_powershell_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • ScriptBlockText
  • Computer
  • UserID
  • EventCode

How To Implement

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

RBA

Risk Score Impact Confidence Message
49.0 70 70 A PowerShell script was identified possibly performing screen captures on $Computer$.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

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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