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https://github.com/splunk/security_content
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Gowthamaraj rajendran
79 lines
3.5 KiB
YAML
79 lines
3.5 KiB
YAML
name: Windows Command Shell Fetch Env Variables
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id: 048839e4-1eaa-43ff-8a22-86d17f6fcc13
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version: 1
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date: '2022-10-27'
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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 identifies a suspicious process command line fetching
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the environment variables with a non-shell parent process. This technique was seen
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in qakbot malware where it fetches the environment variable in the target or compromised
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host. This TTP detection is a good pivot of possible malicious behavior since the
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command line is executed by a common non-shell process like cmd.exe , powershell.exe
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and many more. This can also be a good sign that the parent process has a malicious
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code injected to it to execute this command.
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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 = "*cmd /c
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set" OR Processes.process = "*cmd.exe /c set" AND NOT (Processes.parent_process_name
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= "cmd.exe" OR Processes.parent_process_name = "powershell*" OR Processes.parent_process_name="pwsh.exe"
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OR Processes.parent_process_name = "explorer.exe") by Processes.dest Processes.user
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Processes.parent_process_name Processes.process_name Processes.process Processes.process_id
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Processes.parent_process_id Processes.original_file_name | `drop_dm_object_name(Processes)`
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| `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_command_shell_fetch_env_variables_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: shell process that are not included in this search may cause
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False positive. Filter is needed.
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references:
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- https://twitter.com/pr0xylife/status/1585612370441031680?s=46&t=Dc3CJi4AnM-8rNoacLbScg
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tags:
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analytic_story:
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- Qakbot
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asset_type: Endpoint
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confidence: 70
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impact: 80
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message: non-shell parent process has a child process $process_name$ with a commandline
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$process$ to fetch env variables in $dest$
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mitre_attack_id:
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- T1055
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observable:
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- name: dest
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type: Endpoint
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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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- 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: 56
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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/malware/qakbot/qbot_wermgr/sysmon_wermgr.log
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source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
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sourcetype: xmlwineventlog
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update_timestamp: true
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