mirror of
https://github.com/splunk/security_content
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Gowthamaraj rajendran
87 lines
3.3 KiB
YAML
87 lines
3.3 KiB
YAML
name: Linux SSH Authorized Keys Modification
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id: f5ab595e-28e5-4327-8077-5008ba97c850
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version: 1
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date: '2022-07-27'
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author: Michael Haag, Splunk
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status: production
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type: Anomaly
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description: The following analytic identifies based on process execution the modification
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of SSH Authorized Keys. Adversaries perform this behavior to persist on endpoints.
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During triage, review parallel processes and capture any additional file modifications
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for review.
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data_source:
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- Sysmon Event ID 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.process_name IN ("bash","cat")
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Processes.process IN ("*/authorized_keys*") by Processes.dest Processes.user Processes.parent_process_name
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Processes.process_name Processes.process Processes.process_id Processes.parent_process_id
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| `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
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| `linux_ssh_authorized_keys_modification_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: Filtering will be required as system administrators will add
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and remove. One way to filter query is to add "echo".
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references:
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- https://redcanary.com/blog/lateral-movement-with-secure-shell/
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- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1098.004/T1098.004.md
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tags:
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analytic_story:
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- Linux Living Off The Land
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asset_type: Endpoint
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confidence: 50
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impact: 30
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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 $user$ modifying SSH Authorized Keys.
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mitre_attack_id:
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- T1098.004
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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.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: 15
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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/T1098.004/ssh_authorized_keys/authkey_linux-sysmon.log
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source: Syslog:Linux-Sysmon/Operational
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sourcetype: sysmon_linux
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update_timestamp: true
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