mirror of
https://github.com/splunk/security_content
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divious1
115 lines
4.0 KiB
YAML
115 lines
4.0 KiB
YAML
asset_type: Endpoint
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confidence: medium
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creation_date: '2017-04-25'
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data_metadata:
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data_models:
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- Endpoint
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data_source:
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- Endpoint Intel
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providing_technologies:
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- Carbon Black Response
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- CrowdStrike Falcon
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- Sysmon
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- Tanium
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- Ziften
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description: This search looks for PowerShell processes launched with arguments that
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have characters indicative of obfuscation on the command-line.
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detect:
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splunk:
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correlation_rule:
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notable:
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nes_fields: dest, user, process_name, process
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rule_description: The system $dest$ executed a PowerShell process that has
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evidence of obfuscation on the command-line
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rule_title: PowerShell process with an obfuscation techniques detected on
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$dest$
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risk:
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risk_object: dest
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risk_object_type:
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- system
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risk_score: 60
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schedule:
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cron_schedule: 0 * * * *
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earliest_time: -70m@m
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latest_time: -10m@m
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search: '| tstats `security_content_summariesonly` count values(Processes.process) as process
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values(Processes.parent_process) as parent_process min(_time) as firstTime
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max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=powershell.exe
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by Processes.user Processes.process_name Processes.parent_process_name Processes.dest |
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`drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`| `security_content_ctime(lastTime)`|
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eval num_obfuscation = (mvcount(split(process, "`"))-1) + (mvcount(split(process,
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"^"))-1) | search num_obfuscation > 0'
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suppress:
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suppress_fields: dest,process_name,process
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suppress_period: 14400s
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eli5: This search looks for PowerShell processes that are passing command-line arguments
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with unusual characters (backticks and carets) that are PowerShell specific escape
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characters. Attackers use this obfuscation technique since it does not affect the
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functionality of PowerShell and it will bypass standard security controls that look
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for straight up malicious strings and commands. The search counts the occurrence
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of these obfuscation characters and lists out destination IPs running these PowerShell
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commands.
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entities:
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- dest
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how_to_implement: You must be ingesting data that records process activity from your
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hosts to populate the Endpoint data model in the Processes node. You must also be
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ingesting logs with both the process name and command line from your endpoints.
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The command-line arguments are mapped to the "process" field in the Endpoint data
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model.
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id: cde75cf6-3c7a-4dd6-af01-27cdb4511fd4
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investigations:
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- id: bc91a8cf-35e7-4bb2-8140-e756cc06fd76
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name: Get Authentication Logs For Endpoint
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type: splunk
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- id: fdcfb369-1725-4c24-824a-22972d7f0d55
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name: Get Risk Modifiers For User
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type: splunk
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- id: bc91a8cf-35e7-4bb2-8140-e756cc06fd71
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name: Get Process Info
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type: splunk
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- id: 3d6c3213-5fff-4a1e-b57d-b24c262171e7
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name: Get Notable History
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type: splunk
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- id: f3fb4d1b-5f33-4b01-b541-c7af9534c242
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name: Get Notable Info
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type: splunk
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- id: fdcfb369-1725-4c24-824a-22972d7f0d65
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name: Get Risk Modifiers For Endpoint
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type: splunk
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- id: bc91a8cf-35e7-4bb2-8140-e756cc06fd74
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name: Get User Information from Identity Table
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type: splunk
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known_false_positives: These characters might be legitimately on the command-line,
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but it is not common.
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maintainers:
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- company: Splunk
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email: davidd@splunk.com
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name: David Dorsey
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mappings:
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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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kill_chain_phases:
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- Command and Control
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- Actions on Objectives
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mitre_attack:
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- Execution
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- PowerShell
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- Scripting
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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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modification_date: '2018-12-03'
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name: Malicious PowerShell Process With Obfuscation Techniques
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original_authors:
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- company: Splunk
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email: davidd@splunk.com
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name: David Dorsey
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references: []
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security_domain: endpoint
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spec_version: 2
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type: splunk
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version: '2.0'
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