Sigma Rule Library

Access To Browser Credential Files By Uncommon Applications

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

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Detection logic

selection_ie

FileName|endswith: \Appdata\Local\Microsoft\Windows\WebCache\WebCacheV01.dat

selection_firefox

FileName|endswith:
  - \cookies.sqlite
  - \places.sqlite
  - release\key3.db
  - release\key4.db
  - release\logins.json

selection_chromium

FileName|contains:
  - \User Data\Default\Login Data
  - \User Data\Local State

filter_main_system

Image: System

filter_main_generic

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_*

Raw YAML

title: Access To Browser Credential Files By Uncommon Applications
id: 91cb43db-302a-47e3-b3c8-7ede481e27bf
related:
    - id: 4b60e527-ec73-4b47-8cb3-f02ad927ca65
      type: similar
status: test
description: |
    Detects file access requests to browser credential stores by uncommon processes.
    Could indicate potential attempt of credential stealing.
    Requires heavy baselining before usage
references:
    - https://www.zscaler.com/blogs/security-research/ffdroider-stealer-targeting-social-media-platform-users
    - https://github.com/lclevy/firepwd
author: frack113, X__Junior (Nextron Systems)
date: 2022-04-09
modified: 2024-07-29
tags:
    - attack.t1003
    - attack.credential-access
    - detection.threat-hunting
logsource:
    category: file_access
    product: windows
    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_*
falsepositives:
    - Antivirus, Anti-Spyware, Anti-Malware Software
    - Backup software
    - Legitimate software installed on partitions other than "C:\"
    - Searching software such as "everything.exe"
level: low

False positives

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

References

Similar rules