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78 lines
2.8 KiB
YAML
78 lines
2.8 KiB
YAML
name: SAM Database File Access Attempt
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id: 57551656-ebdb-11eb-afdf-acde48001122
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version: 1
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date: '2021-07-23'
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author: Michael Haag, Mauricio Velazco, Splunk
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type: Hunting
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datamodel:
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- Endpoint
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description: The following analytic identifies access to SAM, SYSTEM or SECURITY databases'
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within the file path of `windows\system32\config` using Windows Security EventCode
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4663. This particular behavior is related to credential access, an attempt to either
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use a Shadow Copy or recent CVE-2021-36934 to access the SAM database. The Security
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Account Manager (SAM) is a database file in Windows XP, Windows Vista, Windows 7,
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8.1 and 10 that stores users' passwords.
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search: '`wineventlog_security` (EventCode=4663) process_name!=*\\dllhost.exe Object_Name
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IN ("*\\Windows\\System32\\config\\SAM*","*\\Windows\\System32\\config\\SYSTEM*","*\\Windows\\System32\\config\\SECURITY*")
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| stats values(Accesses) count by process_name Object_Name dest user | `sam_database_file_access_attempt_filter`'
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how_to_implement: To successfully implement this search, you must ingest Windows Security
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Event logs and track event code 4663. For 4663, enable "Audit Object Access" in
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Group Policy. Then check the two boxes listed for both "Success" and "Failure."
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known_false_positives: Natively, `dllhost.exe` will access the files. Every environment
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will have additional native processes that do as well. Filter by process_name. As
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an aside, one can remove process_name entirely and add `Object_Name=*ShadowCopy*`.
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references:
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- https://www.ultimatewindowssecurity.com/securitylog/encyclopedia/event.aspx?eventID=4663
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- https://docs.microsoft.com/en-us/windows/security/threat-protection/auditing/event-4663
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- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-36934
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- https://github.com/GossiTheDog/HiveNightmare
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- https://github.com/JumpsecLabs/Guidance-Advice/tree/main/SAM_Permissions
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- https://en.wikipedia.org/wiki/Security_Account_Manager
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tags:
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analytic_story:
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- Credential Dumping
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confidence: 100
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context:
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- Source:Endpoint
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- Stage:Credential Access
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cve:
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- CVE-2021-36934
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impact: 80
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kill_chain_phases:
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- Exploitation
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message: The following process $process_name$ accessed the object $Object_Name$
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attempting to gain access to credentials on $dest$ by user $user$.
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mitre_attack_id:
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- T1003.002
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- T1003
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observable:
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- name: user
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type: User
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role:
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- Victim
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- name: dest
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type: Hostname
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role:
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- Victim
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- name: process_name
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type: Process
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role:
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- Child Process
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- name: Object_Name
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type: File
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role:
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- Other
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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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required_fields:
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- _time
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- process_name
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- Object_Name
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- dest
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- user
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risk_score: 80
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security_domain: endpoint
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asset_type: Endpoint
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