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tccontre
84 lines
2.8 KiB
YAML
84 lines
2.8 KiB
YAML
name: Malicious PowerShell Process - Execution Policy Bypass
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id: 9be56c82-b1cc-4318-87eb-d138afaaca39
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version: 5
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date: '2020-07-21'
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author: Rico Valdez, Mauricio Velazco, Splunk
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type: TTP
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datamodel:
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- Endpoint
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description: This search looks for PowerShell processes started with parameters used
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to bypass the local execution policy for scripts. These parameters are often observed
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in attacks leveraging PowerShell scripts as they override the default PowerShell
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execution policy.
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search: '| tstats `security_content_summariesonly` values(Processes.process_id) as
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process_id, values(Processes.parent_process_id) as parent_process_id values(Processes.process)
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as process min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes
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where `process_powershell` (Processes.process="* -ex*" OR Processes.process="* bypass
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*") by Processes.process_id, Processes.user, Processes.dest | `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `malicious_powershell_process___execution_policy_bypass_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 `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: There may be legitimate reasons to bypass the PowerShell execution
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policy. The PowerShell script being run with this parameter should be validated
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to ensure that it is legitimate.
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references: []
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tags:
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analytic_story:
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- DHS Report TA18-074A
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- HAFNIUM Group
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- DarkCrystal RAT
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asset_type: Endpoint
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cis20:
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- CIS 3
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- CIS 7
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- CIS 8
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confidence: 60
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context:
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- Source:Endpoint
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- Stage:Initial Access
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- Stage:Execution
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- Stage:Defense Evasion
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1059.001/encoded_powershell/windows-sysmon.log
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impact: 70
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kill_chain_phases:
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- Command & Control
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- Actions on Objectives
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message: PowerShell local execution policy bypass attempt on $dest$
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mitre_attack_id:
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- T1059
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- T1059.001
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nist:
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- PR.PT
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- DE.CM
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- PR.IP
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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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- Processes.dest
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- Processes.user
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- Processes.parent_process_name
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- Processes.parent_process
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- Processes.original_file_name
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- Processes.process_name
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- Processes.process
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- Processes.process_id
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- Processes.parent_process_path
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- Processes.process_path
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- Processes.parent_process_id
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risk_score: 42
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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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