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P4T12ICK
83 lines
3.0 KiB
YAML
83 lines
3.0 KiB
YAML
name: Malicious PowerShell Process - Encoded Command
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id: c4db14d9-7909-48b4-a054-aa14d89dbb19
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version: 7
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date: '2022-01-18'
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author: David Dorsey, Michael Haag, Splunk
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status: production
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type: Hunting
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description: 'The following analytic identifies the use of the EncodedCommand PowerShell
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parameter. This is typically used by Administrators to run complex scripts, but
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commonly used by adversaries to hide their code. \
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The analytic identifies all variations of EncodedCommand, as PowerShell allows the
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ability to shorten the parameter. For example enc, enco, encod and so forth. In
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addition, through our research it was identified that PowerShell will interpret
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different command switch types beyond the hyphen. We have added endash, emdash,
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horizontal bar, and forward slash. \
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During triage, review parallel events to determine legitimacy. Tune as needed based
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on admin scripts in use. \
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Alternatively, may use regex per matching here https://regexr.com/662ov.'
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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: pwsh.dll
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selection2:
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Image|endswith:
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- pwsh.exe
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- sqlps.exe
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- sqltoolsps.exe
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- powershell.exe
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- powershell_ise.exe
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selection3:
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OriginalFileName: PowerShell.EXE
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selection4:
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OriginalFileName: powershell_ise.EXE
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condition: (selection1 or selection2 or selection3 or selection4)
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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: System administrators may use this option, but it's not common.
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references:
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- https://regexr.com/662ov
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- https://github.com/redcanaryco/AtomicTestHarnesses/blob/master/TestHarnesses/T1059.001_PowerShell/OutPowerShellCommandLineParameter.ps1
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- https://ss64.com/ps/powershell.html
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- https://twitter.com/M_haggis/status/1440758396534214658?s=20
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- https://www.microsoft.com/security/blog/2022/01/15/destructive-malware-targeting-ukrainian-organizations/
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tags:
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analytic_story:
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- Hermetic Wiper
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- Malicious PowerShell
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- NOBELIUM Group
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- WhisperGate
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- DarkCrystal RAT
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- Qakbot
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- CISA AA22-320A
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asset_type: Endpoint
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confidence: 50
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impact: 70
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message: Powershell.exe running potentially malicious encodede commands on $dest$
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mitre_attack_id:
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- T1027
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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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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/T1027/atomic_red_team/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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