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The following analytic detects non-Firefox processes accessing the Firefox profile directory, which contains sensitive user data such as login credentials, browsing history, and cookies. It leverages Windows Security Event logs, specifically event code 4663, to monitor access attempts. This activity is significant because it may indicate attempts by malware, such as RATs or trojans, to harvest user information. If confirmed malicious, this behavior could lead to data exfiltration, unauthorized access to user accounts, and further compromise of the affected system.

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

  • Last Updated: 2024-05-19
  • Author: Teoderick Contreras, Splunk
  • ID: e6fc13b0-1609-11ec-b533-acde48001122




ID Technique Tactic
T1555 Credentials from Password Stores Credential Access
T1555.003 Credentials from Web Browsers Credential Access
Kill Chain Phase
  • Exploitation
  • DE.AE
  • CIS 10
`wineventlog_security` EventCode=4663 NOT (ProcessName IN ("*\\firefox.exe", "*\\explorer.exe", "*sql*")) ObjectName="*\\AppData\\Roaming\\Mozilla\\Firefox\\Profiles*" 
| stats count min(_time) as firstTime max(_time) as lastTime by ObjectName ObjectType ProcessName AccessMask EventCode dest 
| `security_content_ctime(firstTime)` 
| `security_content_ctime(lastTime)` 
| `non_firefox_process_access_firefox_profile_dir_filter`


The SPL above uses the following Macros:

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

Required fields

List of fields required to use this analytic.

  • _time
  • Object_Name
  • Object_Type
  • process_name
  • Access_Mask
  • Accesses
  • process_id
  • EventCode
  • dest
  • user

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."

Known False Positives

other browser not listed related to firefox may catch by this rule.

Associated Analytic Story


Risk Score Impact Confidence Message
35.0 50 70 a non firefox browser process $ProcessName$ accessing $ObjectName$

: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.


Test Dataset

Replay any dataset to Splunk Enterprise by using our tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 3