Potentially malicious execution on command line

detections/endpoint/potentially_malicious_code_on_commandline.yml

@@ -0,0 +1,47 @@
+name: Potentially malicious code on commandline
+id: 9c53c446-757e-11ec-871d-acde48001122
+version: 1
+date: '2022-01-14'
+author: Michael Hart, Splunk
+type: Anomaly
+datamodel:
+- Endpoint
+description: Uses machine learning to detect potentially malicious command lines
+search: '| tstats count from datamodel="Endpoint.Processes" by Processes.process | `drop_dm_object_name(Processes)`  | `unusual_commandline_detection_tokenizer`'
+how_to_implement: UPDATE_HOW_TO_IMPLEMENT
+known_false_positives: UPDATE_KNOWN_FALSE_POSITIVES
+references:
+-  
+tags:
+  analytic_story:
+  - Suspicious Command-Line Executions
+  dataset:
+  - https://github.com/splunk/attack_data/blob/master/datasets/attack_techniques/T1059.001/malicious_cmd_line_samples/windows-sysmon.log
+  kill_chain_phases:
+  - Exploitation
+  mitre_attack_id:
+  - T1059.001
+  - T1059.003
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  security_domain: endpoint
+  impact: 60
+  confidence: 20
+  risk_score: 12
+  context:
+    - source:endpoint
+    - stage:Execution
+  message: Unusual commandline execution with hallmarks of malicious activity found $Message$
+  observable:
+    - name: ComputerName
+      type: Hostname
+      role:
+        - Victim
+    - name: User
+      type: User
+      role:
+        - Victim

macros/potentially_malicious_code_on_cmdline_tokenize_score.yml

@@ -0,0 +1,3 @@
+definition: eval orig_process=process, process=replace(lower(process), "`", "") | makemv tokenizer="([\w\d\-]+)" process | eval unusual_cmdline_feature_for=if(match(process, "^for$"), mvcount(mvfilter(match(process, "^for$"))), 0), unusual_cmdline_feature_netsh=if(match(process, "^netsh$"), mvcount(mvfilter(match(process, "^netsh$"))), 0), unusual_cmdline_feature_readbytes=if(match(process, "^readbytes$"), mvcount(mvfilter(match(process, "^readbytes$"))), 0), unusual_cmdline_feature_set=if(match(process, "^set$"), mvcount(mvfilter(match(process, "^set$"))), 0), unusual_cmdline_feature_unrestricted=if(match(process, "^unrestricted$"), mvcount(mvfilter(match(process, "^unrestricted$"))), 0), unusual_cmdline_feature_winstations=if(match(process, "^winstations$"), mvcount(mvfilter(match(process, "^winstations$"))), 0), unusual_cmdline_feature_-value=if(match(process, "^-value$"), mvcount(mvfilter(match(process, "^-value$"))), 0), unusual_cmdline_feature_compression=if(match(process, "^compression$"), mvcount(mvfilter(match(process, "^compression$"))), 0), unusual_cmdline_feature_server=if(match(process, "^server$"), mvcount(mvfilter(match(process, "^server$"))), 0), unusual_cmdline_feature_set-mppreference=if(match(process, "^set-mppreference$"), mvcount(mvfilter(match(process, "^set-mppreference$"))), 0), unusual_cmdline_feature_terminal=if(match(process, "^terminal$"), mvcount(mvfilter(match(process, "^terminal$"))), 0), unusual_cmdline_feature_-name=if(match(process, "^-name$"), mvcount(mvfilter(match(process, "^-name$"))), 0), unusual_cmdline_feature_catch=if(match(process, "^catch$"), mvcount(mvfilter(match(process, "^catch$"))), 0), unusual_cmdline_feature_get-wmiobject=if(match(process, "^get-wmiobject$"), mvcount(mvfilter(match(process, "^get-wmiobject$"))), 0), unusual_cmdline_feature_hklm=if(match(process, "^hklm$"), mvcount(mvfilter(match(process, "^hklm$"))), 0), unusual_cmdline_feature_streamreader=if(match(process, "^streamreader$"), mvcount(mvfilter(match(process, "^streamreader$"))), 0), unusual_cmdline_feature_system32=if(match(process, "^system32$"), mvcount(mvfilter(match(process, "^system32$"))), 0), unusual_cmdline_feature_username=if(match(process, "^username$"), mvcount(mvfilter(match(process, "^username$"))), 0), unusual_cmdline_feature_webrequest=if(match(process, "^webrequest$"), mvcount(mvfilter(match(process, "^webrequest$"))), 0), unusual_cmdline_feature_count=if(match(process, "^count$"), mvcount(mvfilter(match(process, "^count$"))), 0), unusual_cmdline_feature_webclient=if(match(process, "^webclient$"), mvcount(mvfilter(match(process, "^webclient$"))), 0), unusual_cmdline_feature_writeallbytes=if(match(process, "^writeallbytes$"), mvcount(mvfilter(match(process, "^writeallbytes$"))), 0), unusual_cmdline_feature_convert=if(match(process, "^convert$"), mvcount(mvfilter(match(process, "^convert$"))), 0), unusual_cmdline_feature_create=if(match(process, "^create$"), mvcount(mvfilter(match(process, "^create$"))), 0), unusual_cmdline_feature_function=if(match(process, "^function$"), mvcount(mvfilter(match(process, "^function$"))), 0), unusual_cmdline_feature_net=if(match(process, "^net$"), mvcount(mvfilter(match(process, "^net$"))), 0), unusual_cmdline_feature_com=if(match(process, "^com$"), mvcount(mvfilter(match(process, "^com$"))), 0), unusual_cmdline_feature_http=if(match(process, "^http$"), mvcount(mvfilter(match(process, "^http$"))), 0), unusual_cmdline_feature_io=if(match(process, "^io$"), mvcount(mvfilter(match(process, "^io$"))), 0), unusual_cmdline_feature_system=if(match(process, "^system$"), mvcount(mvfilter(match(process, "^system$"))), 0), unusual_cmdline_feature_new-object=if(match(process, "^new-object$"), mvcount(mvfilter(match(process, "^new-object$"))), 0), unusual_cmdline_feature_if=if(match(process, "^if$"), mvcount(mvfilter(match(process, "^if$"))), 0), unusual_cmdline_feature_threading=if(match(process, "^threading$"), mvcount(mvfilter(match(process, "^threading$"))), 0), unusual_cmdline_feature_mutex=if(match(process, "^mutex$"), mvcount(mvfilter(match(process, "^mutex$"))), 0), unusual_cmdline_feature_cryptography=if(match(process, "^cryptography$"), mvcount(mvfilter(match(process, "^cryptography$"))), 0), unusual_cmdline_feature_computehash=if(match(process, "^computehash$"), mvcount(mvfilter(match(process, "^computehash$"))), 0) | apply unusual_commandline_detection | eval score='predicted(unusual_cmdline_logits)', process=orig_process | fields - unusual_cmdline* predicted(unusual_cmdline_logits) orig_process
+description: Performs the tokenization and application of the malicious commandline classifier
+name: potentially_malicious_code_on_cmdline_tokenize_score

tests/endpoint/potentially_malicious_code_on_commandline.test.yml

@@ -0,0 +1,12 @@
+name: Potentially malicious code on commandline Unit Test
+tests:
+- name: Potentially malicious code on commandline
+  file: endpoint/potentially_malicious_code_on_commandline.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: '-24h'
+  latest_time: 'now'
+  attack_data:
+  - file_name: UPDATE_FILE_NAME
+    data: UPDATE_DATASET_URL
+    source: UPDATE_SPLUNK_SOURCE
+    sourcetype: UPDATE_SPLUNK_SOURCETYPE