mirror of
https://github.com/splunk/security_content
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Bhavin Patel
91 lines
3.7 KiB
YAML
91 lines
3.7 KiB
YAML
name: Batch File Write to System32
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id: 503d17cb-9eab-4cf8-a20e-01d5c6987ae3
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version: 5
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date: '2024-05-19'
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author: Steven Dick, Michael Haag, Rico Valdez, Splunk
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status: production
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type: TTP
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description: The following analytic detects the creation of a batch file (.bat) within
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the Windows system directory tree, specifically in the System32 or SysWOW64 folders.
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It leverages data from the Endpoint datamodel, focusing on process and filesystem
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events to identify this behavior. This activity is significant because writing batch
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files to system directories can be indicative of malicious intent, such as persistence
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mechanisms or system manipulation. If confirmed malicious, this could allow an attacker
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to execute arbitrary commands with elevated privileges, potentially compromising
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the entire system.
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data_source:
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- Sysmon Event ID 1
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search: '| tstats `security_content_summariesonly` count FROM datamodel=Endpoint.Processes
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where Processes.process_name=* by _time span=1h Processes.process_guid Processes.process_name
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Processes.dest Processes.user | `drop_dm_object_name(Processes)` | join process_guid
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[| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
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as lastTime FROM datamodel=Endpoint.Filesystem where Filesystem.file_path IN ("*\\system32\\*",
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"*\\syswow64\\*") Filesystem.file_name="*.bat" by _time span=1h Filesystem.dest
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Filesystem.file_create_time Filesystem.file_name Filesystem.file_path Filesystem.process_guid
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| `drop_dm_object_name(Filesystem)`] | table dest user file_create_time, file_name,
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file_path, process_name, firstTime, lastTime | dedup file_create_time | `security_content_ctime(firstTime)`
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| `security_content_ctime(lastTime)` | `batch_file_write_to_system32_filter`'
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how_to_implement: To successfully implement this search you need to be ingesting information
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on process that include the name of the process responsible for the changes from
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your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
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confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
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endpoint product.
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known_false_positives: It is possible for this search to generate a notable event
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for a batch file write to a path that includes the string "system32", but is not
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the actual Windows system directory. As such, you should confirm the path of the
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batch file identified by the search. In addition, a false positive may be generated
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by an administrator copying a legitimate batch file in this directory tree. You
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should confirm that the activity is legitimate and modify the search to add exclusions,
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as necessary.
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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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asset_type: Endpoint
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confidence: 90
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impact: 70
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message: A file - $file_name$ was written to system32 has occurred on endpoint $dest$
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by user $user$.
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mitre_attack_id:
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- T1204
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- T1204.002
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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.dest
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- Filesystem.file_create_time
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- Filesystem.file_name
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- Filesystem.user
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- Filesystem.file_path
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- Processes.process_name
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- Processes.dest
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- Filesystem.process_guid
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- Processes.process_guid
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- Processes.dest
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- Processes.process_name
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risk_score: 63
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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/T1204.002/batch_file_in_system32/windows-sysmon.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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