Windows Input Capture Using Credential UI Dll

SPLUNK detection rule by Teoderick Contreras, Splunk · Apache-2.0

The following analytic detects a process loading the credui.dll or wincredui.dll module. This detection leverages Sysmon EventCode 7 to identify instances where these DLLs are loaded by processes outside typical system directories. This activity is significant because adversaries often abuse these modules to create fake credential prompts or dump credentials, posing a risk of credential theft. If confirmed malicious, this activity could allow attackers to harvest user credentials, leading to unauthorized access and potential lateral movement within the network.

name: Windows Input Capture Using Credential UI Dll
id: 406c21d6-6c75-4e9f-9ca9-48049a1dd90e
version: 9
creation_date: '2022-08-31'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Hunting
description: The following analytic detects a process loading the credui.dll or wincredui.dll module. This detection leverages Sysmon EventCode 7 to identify instances where these DLLs are loaded by processes outside typical system directories. This activity is significant because adversaries often abuse these modules to create fake credential prompts or dump credentials, posing a risk of credential theft. If confirmed malicious, this activity could allow attackers to harvest user credentials, leading to unauthorized access and potential lateral movement within the network.
data_source:
    - Sysmon EventID 7
search: '`sysmon` EventCode=7  (ImageLoaded = "*\\credui.dll" AND OriginalFileName = "credui.dll") OR (ImageLoaded = "*\\wincredui.dll" AND OriginalFileName = "wincredui.dll") AND NOT(Image IN("*\\windows\\explorer.exe", "*\\windows\\system32\\*", "*\\windows\\sysWow64\\*", "*:\\program files*")) | fillnull | stats count min(_time) as firstTime max(_time) as lastTime by Image ImageLoaded dest loaded_file loaded_file_path original_file_name process_exec process_guid process_hash process_id process_name process_path service_dll_signature_exists service_dll_signature_verified signature signature_id user_id vendor_product | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_input_capture_using_credential_ui_dll_filter`'
how_to_implement: The latest Sysmon TA 3.0 https://splunkbase.splunk.com/app/5709 will add the ImageLoaded name to the process_name field, allowing this query to work. Use as an example and implement for other products.
known_false_positives: this module can be loaded by a third party application. Filter is needed.
references:
    - https://docs.microsoft.com/en-us/windows/win32/api/wincred/nf-wincred-creduipromptforcredentialsa
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1056.002/T1056.002.md#atomic-test-2---powershell---prompt-user-for-password
analytic_story:
    - Brute Ratel C4
    - APT37 Rustonotto and FadeStealer
asset_type: Endpoint
mitre_attack_id:
    - T1056.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/malware/brute_ratel/iso_version_dll_campaign/sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

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