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https://github.com/splunk/security_content
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Michael Haag
83 lines
3.8 KiB
YAML
83 lines
3.8 KiB
YAML
name: Powershell Disable Security Monitoring
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id: c148a894-dd93-11eb-bf2a-acde48001122
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version: 4
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date: '2024-05-21'
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author: Michael Haag, Splunk
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status: production
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type: TTP
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description: The following analytic identifies attempts to disable Windows Defender
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real-time behavior monitoring via PowerShell commands. It detects the use of specific
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`Set-MpPreference` parameters that disable various security features. This activity
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is significant as it is commonly used by malware such as RATs, bots, or Trojans
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to evade detection by disabling antivirus protections. If confirmed malicious, this
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action could allow an attacker to operate undetected, leading to potential data
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exfiltration, further system compromise, or persistent access within the environment.
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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 where `process_powershell` Processes.process="*set-mppreference*"
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AND Processes.process IN ("*disablerealtimemonitoring*","*disableioavprotection*","*disableintrusionpreventionsystem*","*disablescriptscanning*","*disableblockatfirstseen*","*DisableBehaviorMonitoring*","*drtm
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*","*dioavp *","*dscrptsc *","*dbaf *","*dbm *") by Processes.dest Processes.user
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Processes.parent_process Processes.original_file_name Processes.process_name Processes.process
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Processes.process_id Processes.parent_process_id | `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `powershell_disable_security_monitoring_filter`'
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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: Limited false positives. However, tune based on scripts that
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may perform this action.
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references:
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- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1562.001/T1562.001.md#atomic-test-15---tamper-with-windows-defender-atp-powershell
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- https://docs.microsoft.com/en-us/powershell/module/defender/set-mppreference?view=windowsserver2022-ps
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tags:
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analytic_story:
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- Ransomware
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- Revil Ransomware
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- CISA AA24-241A
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asset_type: Endpoint
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confidence: 50
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impact: 50
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message: Windows Defender Real-time Behavior Monitoring disabled on $dest$
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mitre_attack_id:
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- T1562.001
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- T1562
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observable:
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- name: dest
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type: Hostname
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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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required_fields:
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- _time
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- Processes.dest
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- Processes.user
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- Processes.parent_process_name
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- Processes.parent_process
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- Processes.original_file_name
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- Processes.process_name
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- Processes.process
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- Processes.process_id
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- Processes.parent_process_path
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- Processes.process_path
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- Processes.parent_process_id
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risk_score: 25.0
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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:
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https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1562.001/pwh_defender_disabling/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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