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https://github.com/splunk/security_content
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root
82 lines
3.2 KiB
YAML
82 lines
3.2 KiB
YAML
name: Windows Registry Delete Task SD
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id: ffeb7893-ff06-446f-815b-33ca73224e92
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version: 1
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date: '2022-04-13'
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author: Michael Haag, Splunk
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type: TTP
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datamodel:
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- Endpoint
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description: The following analytic identifies a process attempting to delete a scheduled
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task SD (Security Descriptor) from within the registry path of that task. This may
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occur from a non-standard process running and may not come from reg.exe. This particular
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behavior will remove the actual Task Name from the Task Scheduler GUI and from the
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command-line query - schtasks.exe /query. In addition, in order to perform this
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action, the user context will need to be SYSTEM.
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search: '| tstats `security_content_summariesonly` count from datamodel=Endpoint.Registry
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where Registry.registry_path IN ("*\\Schedule\\TaskCache\\Tree\\*") Registry.user="SYSTEM"
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Registry.registry_value_name="SD" (Registry.action=Deleted OR Registry.action=modified)
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by _time Registry.dest Registry.process_guid Registry.user Registry.registry_path
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Registry.registry_value_name Registry.registry_key_name Registry.registry_value_data
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Registry.status Registry.action | `drop_dm_object_name(Registry)` | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)` | `windows_registry_delete_task_sd_filter`'
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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 `Registry` 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: False positives should be limited as the activity is not common
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to delete ONLY the SD from the registry. Filter as needed. Update the analytic Modified
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or Deleted values based on product that is in the datamodel.
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references:
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- https://www.microsoft.com/security/blog/2022/04/12/tarrask-malware-uses-scheduled-tasks-for-defense-evasion/
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- https://gist.github.com/MHaggis/5f7fd6745915166fc6da863d685e2728
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- https://gist.github.com/MHaggis/b246e2fae6213e762a6e694cabaf0c17
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tags:
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analytic_story:
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- Windows Registry Abuse
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- Windows Persistence Techniques
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asset_type: Endpoint
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cis20:
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- CIS 3
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- CIS 5
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- CIS 16
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confidence: 70
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context:
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- Source:Endpoint
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- Stage:Persistence
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1053.005/taskschedule/sd_delete_windows-sysmon.log
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impact: 70
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kill_chain_phases:
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- Installation
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mitre_attack_id:
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- T1053.005
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- T1562
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nist:
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- DE.CM
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message: A scheduled task security descriptor was deleted from the registry on $dest$.
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observable:
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- name: dest
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type: Endpoint
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role:
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- Victim
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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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- Registry.registry_path
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- Registry.registry_key_name
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- Registry.registry_value_name
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- Registry.dest
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- Processes.process_id
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- Processes.process_name
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- Processes.process
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- Processes.dest
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- Processes.process_guid
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risk_score: 49
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security_domain: endpoint
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supported_tas:
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- Splunk_TA_microsoft_sysmon
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