mirror of
https://github.com/splunk/security_content
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Bhavin Patel
78 lines
2.9 KiB
YAML
78 lines
2.9 KiB
YAML
name: Common Ransomware Notes
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id: ada0f478-84a8-4641-a3f1-d82362d6bd71
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version: 5
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date: '2024-05-22'
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author: David Dorsey, Splunk
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status: production
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type: Hunting
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description: The following analytic detects the creation of files with names commonly
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associated with ransomware notes. It leverages file-system activity data from the
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Endpoint Filesystem data model, typically populated by endpoint detection and response
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(EDR) tools or Sysmon logs. This activity is significant because ransomware notes
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indicate a potential ransomware attack, which can lead to data encryption and extortion.
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If confirmed malicious, this activity could result in significant data loss, operational
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disruption, and financial impact due to ransom demands.
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data_source:
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- Sysmon EventID 11
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search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
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as lastTime values(Filesystem.user) as user values(Filesystem.dest) as dest values(Filesystem.file_path)
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as file_path from datamodel=Endpoint.Filesystem by Filesystem.file_name | `drop_dm_object_name(Filesystem)`
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| `security_content_ctime(lastTime)` | `security_content_ctime(firstTime)` | `ransomware_notes`
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| `common_ransomware_notes_filter`'
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how_to_implement: You must be ingesting data that records file-system activity from
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your hosts to populate the Endpoint Filesystem data-model node. This is typically
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populated via endpoint detection-and-response product, such as Carbon Black, or
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via other endpoint data sources, such as Sysmon. The data used for this search is
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typically generated via logs that report file-system reads and writes.
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known_false_positives: It's possible that a legitimate file could be created with
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the same name used by ransomware note files.
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references: []
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tags:
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analytic_story:
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- SamSam Ransomware
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- Ransomware
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- Ryuk Ransomware
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- Clop Ransomware
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- Chaos Ransomware
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- LockBit Ransomware
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- Rhysida Ransomware
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asset_type: Endpoint
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confidence: 100
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impact: 90
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message: A file - $file_name$ was written to disk on endpoint $dest$ by user $user$,
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this is indicative of a known ransomware note file and should be reviewed immediately.
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mitre_attack_id:
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- T1485
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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: file_name
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type: File Name
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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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- Filesystem.user
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- Filesystem.dest
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- Filesystem.file_path
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- Filesystem.file_name
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risk_score: 90
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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/T1485/ransomware_notes/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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