Detection: Windows Credentials from Password Stores Chrome LocalState Access

Updated Date: 2024-05-19 ID: 3b1d09a8-a26f-473e-a510-6c6613573657 Author: Teoderick Contreras, Splunk Type: Anomaly Product: Splunk Enterprise Security

Description

The following analytic detects non-Chrome processes accessing the Chrome "Local State" file, which contains critical settings and information. It leverages Windows Security Event logs, specifically event code 4663, to identify this behavior. This activity is significant because threat actors can exploit this file to extract the encrypted master key used for decrypting saved passwords in Chrome. If confirmed malicious, this could lead to unauthorized access to sensitive information, posing a severe security risk. Monitoring this anomaly helps identify potential threats and safeguard browser-stored data.

Search

1`wineventlog_security` EventCode=4663 object_file_path="*\\AppData\\Local\\Google\\Chrome\\User Data\\Local State" NOT (process_name IN ("*\\chrome.exe","*:\\Windows\\explorer.exe")) 
2| stats count min(_time) as firstTime max(_time) as lastTime by object_file_name object_file_path process_name process_path  process_id EventCode dest 
3| `security_content_ctime(firstTime)` 
4| `security_content_ctime(lastTime)` 
5| `windows_credentials_from_password_stores_chrome_localstate_access_filter`

Data Source

Name	Platform	Sourcetype	Source	Supported App
Windows Event Log Security 4663	Windows	`'xmlwineventlog'`	`'XmlWinEventLog:Security'`	N/A

Macros Used

Name	Value
security_content_ctime	`convert timeformat="%Y-%m-%dT%H:%M:%S" ctime($field$)`
windows_credentials_from_password_stores_chrome_localstate_access_filter	`search *`

windows_credentials_from_password_stores_chrome_localstate_access_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
T1012	Query Registry	Discovery

KillChainPhase.EXPLOITAITON

NistCategory.DE_AE

Cis18Value.CIS_10

APT32

APT39

APT41

Chimera

Dragonfly

Fox Kitten

Kimsuky

Lazarus Group

OilRig

Stealth Falcon

Threat Group-3390

Turla

Volt Typhoon

ZIRCONIUM

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 must ingest Windows Security Event logs and track event code 4663. For 4663, enable "Audit Object Access" in Group Policy. Then check the two boxes listed for both "Success" and "Failure."

Known False Positives

Uninstall chrome application may access this file and folder path to removed chrome installation in target host. Filter is needed.

Associated Analytic Story

Risk Based Analytics (RBA)

Risk Message	Risk Score	Impact	Confidence
A non-chrome process $process_name$ accessing "Chrome\User Data\Local State" file on $dest$	25	50	50

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

https://malpedia.caad.fkie.fraunhofer.de/details/win.redline_stealer

Detection Testing

Test Type	Status	Dataset	Source	Sourcetype
Validation	✅ Passing	N/A	N/A	N/A
Unit	✅ Passing	Dataset	`XmlWinEventLog:Security`	`XmlWinEventLog`
Integration	✅ Passing	Dataset	`XmlWinEventLog:Security`	`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