Elastic Defend high stable eql

Hollow Image Behavior via Native API

Identifies attempt to perform code injection via image hollowing replacing image mapped memory content with malicious one.

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Detection Logic

api where process.Ext.api.name == "VirtualProtect" and process.Ext.api.behaviors == "hollow_image" and
  process.Ext.api.behaviors == "native_api" and
  process.thread.Ext.call_stack_final_user_module.hash.sha256 like "?*" and
  not _arraysearch(process.thread.Ext.call_stack_final_user_module.code_signature, $entry, $entry.trusted == true) and
  /* ntdll and kernel32 covered in other rules */
  not process.Ext.api.metadata.target_address_name in ("ntdll.dll", "kernel32.dll", "Unknown") and
  not process.thread.Ext.call_stack_final_user_module.path :
                                       ("?:\\windows\\assembly\\nativeimages_*",
                                        "?:\\windows\\installer\\*.tmp",
                                        "c:\\windows\\system32\\dk?win64.dll",
                                        "c:\\windows\\system32\\ntdll.dll",
                                        "c:\\windows\\system32\\lsasrv.dll",
                                        "c:\\windows\\system32\\cpsrt.dll",
                                        "c:\\program files\\*",
                                        "c:\\program files (x86)\\*") and
  not (process.Ext.api.metadata.target_address_name == "clr.dll" and process.Ext.api.parameters.size == 428) and
  not _arraysearch(process.thread.Ext.call_stack, $entry, $entry.symbol_info : "c:\\windows\\sys?????\\ntdll.dll!LdrResolveDelayLoadsFromDll*") and
  not (process.thread.Ext.call_stack_final_user_module.path : "c:\\windows\\system32\\spool\\drivers\\x64\\3\\*.dll" and process.Ext.api.parameters.size <= 4096) and
  not process.thread.Ext.call_stack_final_user_module.hash.sha256 in ("aac0a89af89d77fa1af4a9a97657f4dfb83b97b73ec02502fe72b72c835abe31",
                                                                      "2c20ff3a1c0da227e018d40c15c35a7c27179b3e19be9cd2a6bd9b8770a2d5b3",
                                                                      "7fc60aa75973dae70d84d2d9e5b4222716e316f00374efad8927da584cec813a",
                                                                      "0e103cdf3dfa0416e7cb71940ab2a3f53127e7843e86a2e4621d3a21915c1ff7",
                                                                      "f6686978245410dffddc66015bce1baea96c1c3ed0f9d4c9f476e4cf8cb75afb",
                                                                      "9354d9bdbc7f0779a1a8693296171e13cbe6714c15c9c0f934c67e499fbcdff0",
                                                                      "4772629a7e2380d28e33fdace1d309d805f6c9973fecc3bb7fe6dc1553d137f1",
                                                                      "012773a05c29d8d779b7f529ed4e2919b5c2af260acd5a2bd0fb5efafbf435e1",
                                                                      "64d5ccfb2a51525f66cb00aeb7959abe68024c7cece2c82192aff44300e944f3",
                                                                      "d38de4cdb43df6e9992fb88c477ba1bbca4d43aba8c4296626eac2919a81c697",
                                                                      "2771c5b49d89aff611033d2025b9e0690226a7654d6a5cfc0420b18d8965cc67")

Field Validations

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