mirror of
https://github.com/splunk/security_content
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Bhavin Patel
96 lines
3.9 KiB
YAML
96 lines
3.9 KiB
YAML
name: Detect Regasm Spawning a Process
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id: 72170ec5-f7d2-42f5-aefb-2b8be6aad15f
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version: 4
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date: '2024-05-26'
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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 detects regasm.exe spawning a child process. This
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behavior is identified using data from Endpoint Detection and Response (EDR) agents,
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focusing on process creation events where regasm.exe is the parent process. This
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activity is significant because regasm.exe spawning a process is rare and can indicate
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an attempt to bypass application control mechanisms. If confirmed malicious, this
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could allow an attacker to execute arbitrary code, potentially leading to privilege
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escalation or persistent access within the environment. Immediate investigation
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is recommended to determine the legitimacy of the spawned process and any associated
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activities.
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data_source:
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- Sysmon EventID 1
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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 Processes.parent_process_name=regasm.exe
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NOT (Processes.process_name IN ("conhost.exe")) by Processes.dest Processes.user
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Processes.parent_process Processes.parent_process_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)` | `detect_regasm_spawning_a_process_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: Although unlikely, limited instances of regasm.exe or regsvcs.exe
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may cause a false positive. Filter based endpoint usage, command line arguments,
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or process lineage.
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references:
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- https://attack.mitre.org/techniques/T1218/009/
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- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218.009/T1218.009.md
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- https://lolbas-project.github.io/lolbas/Binaries/Regsvcs/
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- https://lolbas-project.github.io/lolbas/Binaries/Regasm/
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tags:
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analytic_story:
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- Suspicious Regsvcs Regasm Activity
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- Living Off The Land
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- DarkGate Malware
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- Snake Keylogger
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asset_type: Endpoint
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confidence: 80
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impact: 80
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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 $user$ spawning a child process, typically not normal
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behavior for $parent_process_name$.
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mitre_attack_id:
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- T1218
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- T1218.009
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observable:
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- name: user
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type: User
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role:
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- Victim
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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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- name: parent_process_name
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type: Process
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role:
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- Parent Process
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- name: process_name
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type: Process
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role:
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- Child Process
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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.parent_process_name
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- Processes.dest
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- Processes.user
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- Processes.parent_process
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- Processes.process
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- Processes.process_id
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- Processes.parent_process_id
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risk_score: 64
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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/T1218.009/atomic_red_team/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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