Sigma rule: Access To Browser Credential Files By Uncommon Applications

A detection rule from the SigmaHQ repository, shown as its author published it. Dataset version ref-3623238cb311, updated 2024-07-29T00:00:00.000Z.

Rule

Title
Access To Browser Credential Files By Uncommon Applications
Status
test
Level
low
Author
frack113, X__Junior (Nextron Systems)
Date
2022-04-09
Modified
2024-07-29
File
rules-threat-hunting/windows/file/file_access/file_access_win_browsers_credential.yml
Commit
ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects file access requests to browser credential stores by uncommon processes.
Could indicate potential attempt of credential stealing.
Requires heavy baselining before usage

Log source

product
windows
category
file_access
definition
Requirements: Microsoft-Windows-Kernel-File ETW provider

Detection

selection_ie:
    FileName|endswith: '\Appdata\Local\Microsoft\Windows\WebCache\WebCacheV01.dat'
selection_firefox:
    FileName|endswith:
        - '\cookies.sqlite'
        - '\places.sqlite'
        - 'release\key3.db'  # Firefox
        - 'release\key4.db'  # Firefox
        - 'release\logins.json' # Firefox
selection_chromium:
    FileName|contains:
        - '\User Data\Default\Login Data'
        - '\User Data\Local State'
filter_main_system:
    Image: System
filter_main_generic:
    # This filter is added to avoid large amount of FP with 3rd party software. You should remove this in favour of specific filter per-application
    Image|startswith:
        - 'C:\Program Files (x86)\'
        - 'C:\Program Files\'
        - 'C:\Windows\system32\'
        - 'C:\Windows\SysWOW64\'
filter_optional_defender:
    Image|startswith: 'C:\ProgramData\Microsoft\Windows Defender\'
    Image|endswith:
        - '\MpCopyAccelerator.exe'
        - '\MsMpEng.exe'
filter_optional_thor:
    Image|endswith:
        - '\thor.exe'
        - '\thor64.exe'
condition: 1 of selection_* and not 1 of filter_main_* and not 1 of filter_optional_*

False positives (as the rule lists them)

  • Antivirus, Anti-Spyware, Anti-Malware Software
  • Backup software
  • Legitimate software installed on partitions other than "C:\"
  • Searching software such as "everything.exe"

Tags

  • attack.t1003
  • attack.credential-access
  • detection.threat-hunting

MITRE ATT&CK ids this rule names

Related rules

References

Read on 2026-11-03T00:58:21.399Z under licence sigma-drl-1.1@d5f4c36a from https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/file/file_access/file_access_win_browsers_credential.yml

Sources and licences

  • SigmaHQ

    "Access To Browser Credential Files By Uncommon Applications" by frack113, X__Junior (Nextron Systems) (SigmaHQ). Rule: https://github.com/SigmaHQ/sigma/blob/ccbb0369507f796db0b0ae6854c8a2be471b9d84/rules-threat-hunting/windows/file/file_access/file_access_win_browsers_credential.yml.
    Licensed under the Detection Rule License (DRL) 1.1: https://github.com/SigmaHQ/Detection-Rule-License

    Detection Rule License (DRL) 1.1

Cite this page

Dragons Eye Ransomware Tracker, "Sigma rule: Access To Browser Credential Files By Uncommon Applications",
entity page, dataset version ref-3623238cb311, updated 2024-07-29T00:00:00.000Z,
https://ransomware-tracker.com/detections/sigma/91cb43db-302a-47e3-b3c8-7ede481e27bf (accessed 2026-11-03).
Underlying source: SigmaHQ rule 91cb43db-302a-47e3-b3c8-7ede481e27bf, commit ccbb0369507f796db0b0ae6854c8a2be471b9d84.

Pages change. The dataset version identifies the data, but no archive of old versions is kept, so this citation cannot be replayed later.