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Eric
64 lines
3.3 KiB
YAML
64 lines
3.3 KiB
YAML
name: Unusually Long Command Line
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id: c77162d3-f93c-45cc-80c8-22f6a4264e7f
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version: 10
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date: '2025-05-02'
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author: David Dorsey, Splunk
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status: experimental
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type: Anomaly
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description: The following analytic detects unusually long command lines, which may
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indicate malicious activity. It leverages data from Endpoint Detection and Response
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(EDR) agents, focusing on the length of command lines executed on hosts. This behavior
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is significant because attackers often use obfuscated or complex command lines to
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evade detection and execute malicious payloads. If confirmed malicious, this activity
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could lead to data theft, ransomware deployment, or further system compromise. Analysts
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should investigate the source and content of the command line, inspect relevant
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artifacts, and review concurrent processes to identify potential threats.
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data_source:
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- Sysmon EventID 1
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- Windows Event Log Security 4688
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- CrowdStrike ProcessRollup2
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search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
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as lastTime FROM datamodel=Endpoint.Processes by Processes.action Processes.dest
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Processes.original_file_name Processes.parent_process Processes.parent_process_exec
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Processes.parent_process_guid Processes.parent_process_id Processes.parent_process_name
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Processes.parent_process_path Processes.process Processes.process_exec Processes.process_guid
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Processes.process_hash Processes.process_id Processes.process_integrity_level Processes.process_name
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Processes.process_path Processes.user Processes.user_id Processes.vendor_product
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| `drop_dm_object_name("Processes")` | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`| eval
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processlen=len(process) | eventstats stdev(processlen) as stdev, avg(processlen)
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as avg by dest | stats max(processlen) as maxlen, values(stdev) as stdevperhost,
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values(avg) as avgperhost by dest, user, process_name, process | `unusually_long_command_line_filter`
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|eval threshold = 3 | where maxlen > ((threshold*stdevperhost) + avgperhost)'
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how_to_implement: The detection is based on data that originates from Endpoint Detection
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and Response (EDR) agents. These agents are designed to provide security-related
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telemetry from the endpoints where the agent is installed. To implement this search,
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you must ingest logs that contain the process GUID, process name, and parent process.
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Additionally, you must ingest complete command-line executions. These logs must
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be processed using the appropriate Splunk Technology Add-ons that are specific to
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the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
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data model. Use the Splunk Common Information Model (CIM) to normalize the field
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names and speed up the data modeling process.
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known_false_positives: Some legitimate applications start with long command lines.
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references: []
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rba:
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message: Unusually long command line $process_name$ on $dest$
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risk_objects:
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- field: dest
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type: system
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score: 42
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threat_objects:
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- field: process_name
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type: process_name
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tags:
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analytic_story:
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- Suspicious Command-Line Executions
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- Unusual Processes
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- Possible Backdoor Activity Associated With MUDCARP Espionage Campaigns
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- Ransomware
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asset_type: Endpoint
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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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