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https://github.com/splunk/security_content
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Eric
79 lines
4.1 KiB
YAML
79 lines
4.1 KiB
YAML
name: Linux DD File Overwrite
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id: 9b6aae5e-8d85-11ec-b2ae-acde48001122
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version: 6
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date: '2025-05-02'
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author: Teoderick Contreras, Splunk
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status: production
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type: TTP
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description: The following analytic detects the use of the 'dd' command to overwrite
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files on a Linux system. It leverages data from Endpoint Detection and Response
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(EDR) agents, focusing on process execution logs that include command-line details.
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This activity is significant because adversaries often use the 'dd' command to destroy
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or irreversibly overwrite files, disrupting system availability and services. If
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confirmed malicious, this behavior could lead to data destruction, making recovery
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difficult and potentially causing significant operational disruptions.
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data_source:
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- Sysmon for Linux 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.process_name = "dd"
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AND Processes.process = "*of=*" by Processes.action Processes.dest Processes.original_file_name
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Processes.parent_process Processes.parent_process_exec Processes.parent_process_guid
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Processes.parent_process_id Processes.parent_process_name Processes.parent_process_path
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Processes.process Processes.process_exec Processes.process_guid Processes.process_hash
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Processes.process_id Processes.process_integrity_level Processes.process_name Processes.process_path
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Processes.user Processes.user_id Processes.vendor_product | `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `linux_dd_file_overwrite_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: Administrator or network operator can execute this command.
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Please update the filter macros to remove false positives.
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references:
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- https://gtfobins.github.io/gtfobins/dd/
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- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1485/T1485.md
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drilldown_searches:
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- name: View the detection results for - "$dest$"
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search: '%original_detection_search% | search dest = "$dest$"'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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- name: View risk events for the last 7 days for - "$dest$"
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search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$")
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starthoursago=168 | stats count min(_time) as firstTime max(_time) as lastTime
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values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories)
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as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic)
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as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)`'
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earliest_offset: $info_min_time$
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latest_offset: $info_max_time$
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rba:
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message: A commandline $process$ executed 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: 64
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threat_objects: []
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tags:
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analytic_story:
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- Data Destruction
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- Industroyer2
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asset_type: Endpoint
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mitre_attack_id:
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- T1485
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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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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/T1485/linux_dd_file_overwrite/sysmon_linux.log
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source: Syslog:Linux-Sysmon/Operational
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sourcetype: sysmon:linux
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