SAM Registry Hive Handle Request¶

Metadata¶


collaborators	[‘Roberto Rodriguez @Cyb3rWard0g’, ‘Jose Rodriguez @Cyb3rPandaH’]
creation date	2019/07/25
modification date	2020/09/20
playbook related	[‘WIN-190625024610’]

Hypothesis¶

Adversaries might be getting a handle to the SAM database to extract credentials in my environment

Technical Context¶

Every computer that runs Windows has its own local domain; that is, it has an account database for accounts that are specific to that computer. Conceptually,this is an account database like any other with accounts, groups, SIDs, and so on. These are referred to as local accounts, local groups, and so on. Because computers typically do not trust each other for account information, these identities stay local to the computer on which they were created.

Offensive Tradecraft¶

Adversaries might use tools like Mimikatz with lsadump::sam commands or scripts such as Invoke-PowerDump to get the SysKey to decrypt Security Account Mannager (SAM) database entries (from registry or hive) and get NTLM, and sometimes LM hashes of local accounts passwords.

In addition, adversaries can use the built-in Reg.exe utility to dump the SAM hive in order to crack it offline.

Additional reading

https://github.com/OTRF/ThreatHunter-Playbook/tree/master/docs/library/security_account_manager_database.md
https://github.com/OTRF/ThreatHunter-Playbook/tree/master/docs/library/syskey.md

Mordor Test Data¶


metadata	https://mordordatasets.com/notebooks/small/windows/06_credential_access/SDWIN-190625103712.html
link	https://raw.githubusercontent.com/OTRF/mordor/master/datasets/small/windows/credential_access/host/empire_mimikatz_sam_access.zip

Analytics¶

Initialize Analytics Engine¶

from openhunt.mordorutils import *
spark = get_spark()

Download & Process Mordor Dataset¶

mordor_file = "https://raw.githubusercontent.com/OTRF/mordor/master/datasets/small/windows/credential_access/host/empire_mimikatz_sam_access.zip"
registerMordorSQLTable(spark, mordor_file, "mordorTable")

[+] Processing a Spark DataFrame..
[+] DataFrame Returned !
[+] Temporary SparkSQL View: mordorTable 

Analytic I¶

Monitor for any handle requested for the SAM registry hive

Data source	Event Provider	Relationship	Event
Windows registry	Microsoft-Windows-Security-Auditing	Process requested access Windows registry key	4656
Windows registry	Microsoft-Windows-Security-Auditing	User requested access Windows registry key	4656

df = spark.sql(
'''
SELECT `@timestamp`, Hostname, SubjectUserName, ProcessName, ObjectName, AccessMask
FROM mordorTable
WHERE LOWER(Channel) = "security"
    AND EventID = 4656
    AND ObjectType = "Key"
    AND lower(ObjectName) LIKE "%sam"
'''
)
df.show(10,False)

+----------+--------+---------------+-----------+----------+----------+
|@timestamp|Hostname|SubjectUserName|ProcessName|ObjectName|AccessMask|
+----------+--------+---------------+-----------+----------+----------+
+----------+--------+---------------+-----------+----------+----------+

Known Bypasses¶

Idea	Playbook

False Positives¶

None

Hunter Notes¶