Detection: Windows Credentials Access via VaultCli Module

Updated Date: 2024-11-29 ID: c0d89118-3f89-4cd7-8140-1f39e7210681 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

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.

1`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\\*") 
2| stats count min(_time) as firstTime max(_time) as lastTime by dest Image ImageLoaded process_name EventCode Signed ProcessId 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `windows_credentials_access_via_vaultcli_module_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_credentials_access_via_vaultcli_module_filter search *
windows_credentials_access_via_vaultcli_module_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
T1555.004 Windows Credential Manager Credential Access
KillChainPhase.EXPLOITAITON
NistCategory.DE_AE
Cis18Value.CIS_10
OilRig
Stealth Falcon
Turla
Wizard Spider

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 Risk Event True
This configuration file applies to all detections of type anomaly. These detections will use Risk Based Alerting.

Implementation

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.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message Risk Score Impact Confidence
An instance of process name [$process_name$] loading a file [$ImageLoaded$] was identified on endpoint- [$dest$] to potentially capture credentials in memory. 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