mirror of
https://github.com/splunk/security_content
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ljstella
91 lines
4.6 KiB
YAML
91 lines
4.6 KiB
YAML
name: Powershell Processing Stream Of Data
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id: 0d718b52-c9f1-11eb-bc61-acde48001122
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version: 12
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date: '2025-06-24'
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author: Teoderick Contreras, Splunk
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status: production
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type: TTP
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description:
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The following analytic detects suspicious PowerShell script execution
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involving compressed stream data processing, identified via EventCode 4104. It leverages
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PowerShell Script Block Logging to flag scripts using `IO.Compression`, `IO.StreamReader`,
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or decompression methods. This activity is significant as it often indicates obfuscated
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PowerShell or embedded .NET/binary execution, which are common tactics for evading
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detection. If confirmed malicious, this behavior could allow attackers to execute
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hidden code, escalate privileges, or maintain persistence within the environment.
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data_source:
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- Powershell Script Block Logging 4104
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search:
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'`powershell` EventCode=4104 ScriptBlockText = "*IO.Compression.*" OR ScriptBlockText
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= "*IO.StreamReader*" OR ScriptBlockText = "*]::Decompress*" | fillnull | stats
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count min(_time) as firstTime max(_time) as lastTime by dest signature signature_id
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user_id vendor_product EventID Guid Opcode Name Path ProcessID ScriptBlockId ScriptBlockText
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `powershell_processing_stream_of_data_filter`'
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how_to_implement:
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To successfully implement this analytic, you will need to enable
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PowerShell Script Block Logging on some or all endpoints. Additional setup here
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https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba.
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known_false_positives: powershell may used this function to process compressed data.
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references:
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- https://medium.com/@ahmedjouini99/deobfuscating-emotets-powershell-payload-e39fb116f7b9
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- https://help.splunk.com/en/security-offerings/splunk-user-behavior-analytics/get-data-in/5.4.1/add-other-data-to-splunk-uba/configure-powershell-logging-to-see-powershell-anomalies-in-splunk-uba
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- https://blog.palantir.com/tampering-with-windows-event-tracing-background-offense-and-defense-4be7ac62ac63
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- https://static1.squarespace.com/static/552092d5e4b0661088167e5c/t/59c1814829f18782e24f1fe2/1505853768977/Windows+PowerShell+Logging+Cheat+Sheet+ver+Sept+2017+v2.1.pdf
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- https://www.crowdstrike.com/blog/investigating-powershell-command-and-script-logging/
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- https://www.splunk.com/en_us/blog/security/hunting-for-malicious-powershell-using-script-block-logging.html
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- https://thedfirreport.com/2023/05/22/icedid-macro-ends-in-nokoyawa-ransomware/
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drilldown_searches:
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- name: View the detection results for - "$Computer$" and "$user$"
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search: '%original_detection_search% | search Computer = "$Computer$" user = "$user$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$Computer$" and "$user$"
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search:
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'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$Computer$",
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"$user$") starthoursago=168 | stats count min(_time) as firstTime max(_time)
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as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk
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Message" values(analyticstories) as "Analytic Stories" values(annotations._all)
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as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics"
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by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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rba:
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message:
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A suspicious powershell script contains stream command in $ScriptBlockText$
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commonly for processing compressed or to decompressed binary file with EventCode
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$EventID$ in host $dest$
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risk_objects:
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- field: dest
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type: system
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score: 40
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- field: user_id
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type: user
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score: 40
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threat_objects: []
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tags:
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analytic_story:
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- Malicious PowerShell
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- Medusa Ransomware
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- PXA Stealer
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- Data Destruction
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- Braodo Stealer
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- AsyncRAT
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- Hermetic Wiper
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- IcedID
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- XWorm
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- MoonPeak
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asset_type: Endpoint
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mitre_attack_id:
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- T1059.001
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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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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/powershell_script_block_logging/streamreader.log
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source: XmlWinEventLog:Microsoft-Windows-PowerShell/Operational
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sourcetype: XmlWinEventLog
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