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root
97 lines
3.7 KiB
YAML
97 lines
3.7 KiB
YAML
name: Windows Rundll32 Inline HTA Execution
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id: 0caa1dd6-94f5-11ec-9786-acde48001122
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version: 1
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date: '2022-02-23'
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author: Michael Haag, Splunk
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type: TTP
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datamodel:
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- Endpoint_Processes
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description: The following analytic identifies "rundll32.exe" execution with inline
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protocol handlers. "JavaScript", "VBScript", and "About" are the only supported
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options when invoking HTA content directly on the command-line. This type of behavior
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is commonly observed with fileless malware or application whitelisting bypass techniques.
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The search will return the first time and last time these command-line arguments
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were used for these executions, as well as the target system, the user, process
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"rundll32.exe" and its parent process.
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search: '| from read_ssa_enriched_events() | eval timestamp=parse_long(ucast(map_get(input_event,
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"_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"),
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"string", null)), process_name=lower(ucast(map_get(input_event, "process_name"),
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"string", null)), process_path=ucast(map_get(input_event, "process_path"), "string",
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null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string",
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null), event_id=ucast(map_get(input_event, "event_id"), "string", null) | where
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cmd_line IS NOT NULL AND process_name IS NOT NULL | where process_name="rundll32.exe"
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AND (like (cmd_line, "%vbscript%") OR like (cmd_line, "%javascript%") OR like (cmd_line,
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"%about%")) | eval start_time=timestamp, end_time=timestamp, entities=mvappend(ucast(map_get(input_event,
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"dest_user_id"), "string", null), ucast(map_get(input_event, "dest_device_id"),
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"string", null)), body=create_map(["event_id", event_id, "cmd_line", cmd_line, "process_name",
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process_name, "parent_process_name", parent_process_name, "process_path", process_path])
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| into write_ssa_detected_events();'
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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: Although unlikely, some legitimate applications may exhibit
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this behavior, triggering a false positive.
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references:
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- https://github.com/redcanaryco/AtomicTestHarnesses
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- https://redcanary.com/blog/introducing-atomictestharnesses/
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- https://docs.microsoft.com/en-us/windows/win32/search/-search-3x-wds-extidx-prot-implementing
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tags:
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analytic_story:
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- Suspicious MSHTA Activity
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- NOBELIUM Group
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- Living Off The Land
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asset_type: Endpoint
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automated_detection_testing: passed
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cis20:
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- CIS 8
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confidence: 80
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context:
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- Source:Endpoint
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- Stage:Initial Access
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- Stage:Execution
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- Stage:Defense Evasion
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.005/atomic_red_team/windows-security.log
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impact: 70
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kill_chain_phases:
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- Exploitation
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message: Suspicious $process_name$ inline HTA execution on $dest_device_id$.
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mitre_attack_id:
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- T1218
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- T1218.005
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nist:
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- PR.PT
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- DE.CM
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observable:
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- name: dest_user_id
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type: User
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role:
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- Victim
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- name: dest_device_id
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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 Behavioral Analytics
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required_fields:
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- _time
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- dest_device_id
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- process_name
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- parent_process_name
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- process_path
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- dest_user_id
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- process
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- cmd_line
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risk_score: 56
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security_domain: endpoint
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