Detection rules › Splunk

Windows Credentials Access via VaultCli Module

Status
production
Severity
low
Group by
dest, image_loaded, process_guid, process_hash, process_id, process_name, service_dll_signature_exists, service_dll_signature_verified, signature, signature_id, user_id, vendor_product
Author
Teoderick Contreras, Splunk
Source
github.com/splunk/security_content

The following analytic detects potentially abnormal interactions with VaultCLI.dll, particularly those initiated by processes located in publicly writable Windows folder paths. The VaultCLI.dll module allows processes to extract credentials from the Windows Credential Vault. It was seen being abused by information stealers such as Meduza. The analytic monitors suspicious API calls, unauthorized credential access patterns, and anomalous process behaviors indicative of malicious activity. By leveraging a combination of signature-based detection and behavioral analysis, it effectively flags attempts to misuse the vault for credential theft, enabling swift response to protect sensitive user data and ensure system security.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
SysmonEvent ID 7Image loaded

Rule body splunk

name: Windows Credentials Access via VaultCli Module
id: c0d89118-3f89-4cd7-8140-1f39e7210681
version: 9
creation_date: '2024-12-02'
modification_date: '2026-05-13'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: The following analytic detects potentially abnormal interactions with VaultCLI.dll, particularly those initiated by processes located in publicly writable Windows folder paths. The VaultCLI.dll module allows processes to extract credentials from the Windows Credential Vault. It was seen being abused by information stealers such as Meduza. The analytic monitors suspicious API calls, unauthorized credential access patterns, and anomalous process behaviors indicative of malicious activity. By leveraging a combination of signature-based detection and behavioral analysis, it effectively flags attempts to misuse the vault for credential theft, enabling swift response to protect sensitive user data and ensure system security.
data_source:
    - Sysmon EventID 7
search: '`sysmon` EventCode=7  ImageLoaded ="*\\vaultcli.dll" process_path IN("*\\windows\\fonts\\*", "*\\windows\\temp\\*", "*\\users\\public\\*", "*\\windows\\debug\\*", "*\\Users\\Administrator\\Music\\*", "*\\Windows\\servicing\\*", "*\\Users\\Default\\*", "*Recycle.bin*", "*\\Windows\\Media\\*", "\\Windows\\repair\\*", "*\\appdata\\local\\temp\\*", "*\\PerfLogs\\*", "*:\\temp\\*") | 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_credentials_access_via_vaultcli_module_filter`'
how_to_implement: To successfully implement this search, you need to be ingesting logs with the process name and imageloaded executions from your endpoints. If you are using Sysmon, you must have at least version 6.0.4 of the Sysmon TA.
known_false_positives: Third party software might leverage this DLL in order to make use of the Credential Manager feature via the provided exports. Typically the vaultcli.dll module is loaded by the vaultcmd.exe Windows Utility to interact with the Windows Credential Manager for secure storage and retrieval of credentials.
references:
    - https://hijacklibs.net/entries/microsoft/built-in/vaultcli.html
    - https://www.fortinet.com/blog/threat-research/exploiting-cve-2024-21412-stealer-campaign-unleashed
    - https://cert.gov.ua/article/6276652
    - https://cert.gov.ua/article/6281018
    - https://g0njxa.medium.com/approaching-stealers-devs-a-brief-interview-with-meduza-f1bbd2efb84f
drilldown_searches:
    - name: View the detection results for - "$dest$"
      search: '%original_detection_search% | search  dest = "$dest$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$dest$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
      earliest_offset: 7d
      latest_offset: "0"
intermediate_findings:
    entities:
        - field: dest
          type: system
          score: 20
          message: An instance of process $process_name$ loading the file $ImageLoaded$ was identified on endpoint $dest$ to potentially capture credentials in memory.
threat_objects:
    - field: process_name
      type: process_name
analytic_story:
    - Meduza Stealer
    - Hellcat Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1555.004
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/attack_techniques/T1555.004/vaultcli_creds/vaultcli.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: search

`sysmon` EventCode=7  ImageLoaded ="*\\vaultcli.dll" process_path IN("*\\windows\\fonts\\*", "*\\windows\\temp\\*", "*\\users\\public\\*", "*\\windows\\debug\\*", "*\\Users\\Administrator\\Music\\*", "*\\Windows\\servicing\\*", "*\\Users\\Default\\*", "*Recycle.bin*", "*\\Windows\\Media\\*", "\\Windows\\repair\\*", "*\\appdata\\local\\temp\\*", "*\\PerfLogs\\*", "*:\\temp\\*")

Stage 2: fillnull

| fillnull

Stage 3: stats

| 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

Stage 4: search

| `security_content_ctime(firstTime)`

Stage 5: search

| `security_content_ctime(lastTime)`

Stage 6: search

| `windows_credentials_access_via_vaultcli_module_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
EventCodeeq
  • 7 corpus 39 (splunk 38, kusto 1)
ImageLoadedeq
  • "*\\vaultcli.dll"
process_pathin
  • "*:\\temp\\*"
  • "*Recycle.bin*"
  • "*\\PerfLogs\\*"
  • "*\\Users\\Administrator\\Music\\*"
  • "*\\Users\\Default\\*"
  • "*\\Windows\\Media\\*"
  • "*\\Windows\\servicing\\*"
  • "*\\appdata\\local\\temp\\*"
  • "*\\users\\public\\*"
  • "*\\windows\\debug\\*"
  • "*\\windows\\fonts\\*"
  • "*\\windows\\temp\\*"
  • "\\Windows\\repair\\*"