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Description

The following analytic identifies a possible non-common browser process accessing its browser user data profile. This tactic/technique has been observed in various Trojan Stealers, such as SnakeKeylogger, which attempt to gather sensitive browser information and credentials as part of their exfiltration strategy. Detecting this anomaly can serve as a valuable pivot for identifying processes that access lists of browser user data profiles unexpectedly. This detection uses a lookup file browser_app_list that maintains a list of well known browser applications and the browser paths that are allowed to access the browser user data profiles.

  • Type: Anomaly

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

  • Last Updated: 2024-02-20
  • Author: Teoderick Contreras, Bhavin Patel Splunk
  • ID: 72013a8e-5cea-408a-9d51-5585386b4d69

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1012 Query Registry Discovery
Kill Chain Phase
  • Exploitation
NIST
  • DE.AE
CIS20
  • CIS 10
CVE 


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`wineventlog_security` EventCode=4663 
| lookup browser_app_list browser_object_path as object_file_path OUTPUT browser_process_name isAllowed 
| stats count min(_time) as firstTime max(_time) as lastTime values(object_file_name) values(object_file_path)  values(browser_process_name) as browser_process_name by dest process_name process_path process_id EventCode isAllowed 
| rex field=process_name "(?<extracted_process_name>[^\\\\]+)$" 
| eval isMalicious=if(match(browser_process_name, extracted_process_name), "0", "1") 
| where isMalicious=1 and isAllowed="false" 
| `windows_credential_access_from_browser_password_store_filter`

Macros

The SPL above uses the following Macros:

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

Lookups

The SPL above uses the following Lookups:

Required fields

List of fields required to use this analytic.

  • _time
  • object_file_name
  • object_file_path
  • process_name
  • process_path
  • process_id
  • EventCode
  • dest

How To Implement

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." This search may trigger on a browser application that is not included in the browser_app_list lookup file.

Known False Positives

The lookup file browser_app_list may not contain all the browser applications that are allowed to access the browser user data profiles. Consider updating the lookup files to add allowed object paths for the browser applications that are not included in the lookup file.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
25.0 50 50 A non-common browser process $process_name$ accessing browser user data folder on $dest$

: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

source | version: 1