Sigma rule: Access To Windows DPAPI Master Keys By Uncommon Applications

Rule

Title

Access To Windows DPAPI Master Keys By Uncommon Applications

Status

test

Level

medium

Author

Nasreddine Bencherchali (Nextron Systems)

Date

2022-10-17

Modified

2026-07-28

File

rules/windows/file/file_access/file_access_win_susp_dpapi_master_key_access.yml

Commit

ccbb0369507f796db0b0ae6854c8a2be471b9d84

Detects file access requests to the the Windows Data Protection API Master keys by an uncommon application.
This can be a sign of credential stealing. Example case would be usage of mimikatz "dpapi::masterkey" function

Log source

product

windows

category

file_access

definition

Requirements: Microsoft-Windows-Kernel-File ETW provider

Detection

selection:
    FileName|contains:
        - '\Microsoft\Protect\S-1-5-18\' # For System32
        - '\Microsoft\Protect\S-1-5-21-' # For Users
filter_main_system_folders:
    Image|startswith:
        - 'C:\Program Files\'
        - 'C:\Program Files (x86)\'
        - 'C:\Windows\system32\'
        - 'C:\Windows\SysWOW64\'
filter_main_explorer:
    Image: 'C:\Windows\explorer.exe'
condition: selection and not 1 of filter_main_*

False positives (as the rule lists them)

• Unknown

Tags

• attack.credential-access
• attack.t1555.004

MITRE ATT&CK ids this rule names

• T1555.004

References

• http://blog.harmj0y.net/redteaming/operational-guidance-for-offensive-user-dpapi-abuse/
• https://book.hacktricks.xyz/windows-hardening/windows-local-privilege-escalation/dpapi-extracting-passwords

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