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P4T12ICK
71 lines
2.3 KiB
YAML
71 lines
2.3 KiB
YAML
name: Windows DiskCryptor Usage
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id: d56fe0c8-4650-11ec-a8fa-acde48001122
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version: 1
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date: '2021-11-15'
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author: Michael Haag, Splunk
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status: production
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type: Hunting
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description: The following analytic identifies DiskCryptor process name of dcrypt.exe
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or internal name dcinst.exe. This utility has been utilized by adversaries to encrypt
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disks manually during an operation. In addition, during install, a dcrypt.sys driver
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is installed and requires a reboot in order to take effect. There are no command-line
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arguments used.
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data_source:
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- Sysmon Event ID 1
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search:
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selection1:
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OriginalFileName: dcinst.exe
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selection2:
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Image|endswith: dcrypt.exe
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condition: (selection1 or selection2)
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how_to_implement: To successfully implement this search you need to be ingesting information
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on process that include the name of the process responsible for the changes from
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your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
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confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
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endpoint product.
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known_false_positives: It is possible false positives may be present based on the
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internal name dcinst.exe, filter as needed. It may be worthy to alert on the service
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name.
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references:
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- https://thedfirreport.com/2021/11/15/exchange-exploit-leads-to-domain-wide-ransomware/
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- https://github.com/DavidXanatos/DiskCryptor
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tags:
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analytic_story:
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- Ransomware
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asset_type: Endpoint
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confidence: 50
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impact: 70
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message: An instance of $parent_process_name$ spawning $process_name$ was identified
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on endpoint $dest$ by user $user$ attempting to encrypt disks.
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mitre_attack_id:
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- T1486
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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: parent_process_name
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type: Process
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role:
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- Parent Process
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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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product:
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- Splunk Enterprise
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- Splunk Enterprise Security
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- Splunk Cloud
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risk_score: 35
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security_domain: endpoint
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tests:
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- name: True Positive Test
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attack_data:
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- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1486/dcrypt/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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