splunk-security_content/docs/_posts/2021-07-23-sam_database_file_access_attempt.md

title, excerpt, categories, last_modified_at, toc, toc_label, tags

title	excerpt	categories	last_modified_at	toc	toc_label	tags
SAM Database File Access Attempt	Security Account Manager, OS Credential Dumping	Endpoint	2021-07-23	true		Security Account Manager Credential Access OS Credential Dumping Credential Access Splunk Enterprise Splunk Enterprise Security Splunk Cloud CVE-2021-36934 Endpoint

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Description

The following analytic identifies access to SAM, SYSTEM or SECURITY databases' within the file path of windows\system32\config using Windows Security EventCode 4663. This particular behavior is related to credential access, an attempt to either use a Shadow Copy or recent CVE-2021-36934 to access the SAM database. The Security Account Manager (SAM) is a database file in Windows XP, Windows Vista, Windows 7, 8.1 and 10 that stores users' passwords.

• Type: Hunting
• Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud
• Datamodel: Endpoint
• Last Updated: 2021-07-23
• Author: Michael Haag, Mauricio Velazco, Splunk
• ID: 57551656-ebdb-11eb-afdf-acde48001122

ATT&CK

ID	Technique	Tactic
T1003.002	Security Account Manager	Credential Access

| T1003 | OS Credential Dumping | Credential Access |

Search

`wineventlog_security` (EventCode=4663)  process_name!=*\\dllhost.exe Object_Name IN ("*\\Windows\\System32\\config\\SAM*","*\\Windows\\System32\\config\\SYSTEM*","*\\Windows\\System32\\config\\SECURITY*") 
| stats values(Accesses) count by process_name Object_Name  dest user 
| `sam_database_file_access_attempt_filter`

Associated Analytic Story

• Credential Dumping

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."

Required field

• _time
• process_name
• Object_Name
• dest
• user

Kill Chain Phase

• Exploitation

Known False Positives

Natively, dllhost.exe will access the files. Every environment will have additional native processes that do as well. Filter by process_name. As an aside, one can remove process_name entirely and add Object_Name=*ShadowCopy*.

RBA

Risk Score	Impact	Confidence	Message
80.0	80	100	The following process process_name accessed the object Object_Name attempting to gain access to credentials on dest by user user.

CVE

ID	Summary	CVSS
CVE-2021-36934	Windows Elevation of Privilege Vulnerability	4.6

Reference

• https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4663
• https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4663
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934
• https://github.com/GossiTheDog/HiveNightmare
• https://github.com/JumpsecLabs/Guidance-Advice/tree/main/SAM_Permissions
• https://en.wikipedia.org/wiki/Security_Account_Manager

Test Dataset

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

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