mirror of
https://github.com/splunk/security_content
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Eric McGinnis
65 lines
2.5 KiB
YAML
65 lines
2.5 KiB
YAML
name: Windows Powershell DownloadFile
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id: 46440222-81d5-44b1-a376-19dcd70d1b08
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version: 5
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date: '2022-02-11'
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author: Jose Hernandez, Michael Haag, Splunk
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status: production
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type: Anomaly
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description: The following analytic identifies the use of PowerShell downloading a
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file using `DownloadFile` method. This particular method is utilized in many different
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PowerShell frameworks to download files and output to disk. Identify the source
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(IP/domain) and destination file and triage appropriately. If AMSI logging or PowerShell
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transaction logs are available, review for further details of the implant.
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data_source:
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- Windows Security 4688
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search:
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selection1:
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process.file.name:
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- powershell_ise.exe
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- powershell.exe
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- sqltoolsps.exe
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- sqlps.exe
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- pwsh.exe
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- pwsh.exe
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selection2:
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process.cmd_line|re: downloadfile
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condition: selection1 and 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: False positives may be present and filtering will need to occur
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by parent process or command line argument. It may be required to modify this query
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to an EDR product for more granular coverage.
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references:
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- https://docs.microsoft.com/en-us/dotnet/api/system.net.webclient.downloadfile?view=net-5.0
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- https://blog.malwarebytes.com/malwarebytes-news/2021/02/lazyscripter-from-empire-to-double-rat/
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- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1059.001/T1059.001.md
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tags:
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analytic_story:
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- Malicious PowerShell
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- Ingress Tool Transfer
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- Log4Shell CVE-2021-44228
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asset_type: Endpoint
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confidence: 70
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impact: 50
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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 $user$. This behavior identifies the use of DownloadFile
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within PowerShell.
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mitre_attack_id:
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- T1020
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observable: []
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product:
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- Splunk Behavioral Analytics
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required_fields: []
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kill_chain_phases:
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- Exploitation
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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/T1059.001/atomic_red_team/downloadfile_windows-security.log
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source: WinEventLog:Security
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