Suspicious File Rename from Unbacked Memory

[rule]
description = """
Identifies a suspicious file rename operation from an unbacked memory region. This may indicate Ransomware behavior from
an injected trusted process.
"""
id = "adc08f95-6a12-441a-be30-0443d6ccae52"
license = "Elastic License v2"
name = "Suspicious File Rename from Unbacked Memory"
os_list = ["windows"]
version = "1.0.7"

query = '''
sequence by process.entity_id with maxspan=30s
[file where event.action : "rename" and
  process.code_signature.status : "trusted" and
  not process.code_signature.subject_name :
                          ("LEAP SOFTWARE DEVELOPMENTS PTY. LIMITED", "KASEYA US LLC",
                           "Chocolatey Software, Inc.", "Quadient Industrie France", "ACTIFILE LTD") and
  file.extension != null and file.Ext.entropy >= 7 and
  file.Ext.original.name : ("*.jpg", "*.bmp", "*.png", "*.pdf", "*.doc", "*.docx", "*.xls", "*.xlsx", "*.ppt", "*.pptx") and
  not file.extension : ("tmp", "~tmp", "diff", "gz", "download", "bak", "bck", "lnk", "part", "save", "url", "jpg",
                        "bmp", "png", "pdf", "doc", "docx", "xls", "xlsx", "ppt", "pptx") and
  process.thread.Ext.call_stack_summary :
                     ("ntdll.dll|kernelbase.dll|Unbacked",
                      "ntdll.dll|kernelbase.dll|kernel32.dll|Unbacked",
					  "ntdll.dll|kernelbase.dll|Unknown|kernel32.dll|ntdll.dll",
					  "ntdll.dll|kernelbase.dll|Unknown|kernel32.dll|ntdll.dll",
					  "ntdll.dll|kernelbase.dll|kernel32.dll|Unknown|kernel32.dll|ntdll.dll",
                      "ntdll.dll|wow64.dll|wow64cpu.dll|wow64.dll|ntdll.dll|kernelbase.dll|Unbacked",
                      "ntdll.dll|wow64.dll|wow64cpu.dll|wow64.dll|ntdll.dll|kernelbase.dll|Unbacked|kernel32.dll|ntdll.dll",
                      "ntdll.dll|Unbacked",
                      "Unbacked",
					  "Unknown")]
[file where event.action : "rename" and
  process.code_signature.status : "trusted" and
  not process.code_signature.subject_name : ("LEAP SOFTWARE DEVELOPMENTS PTY. LIMITED", "KASEYA US LLC", "Chocolatey Software, Inc.") and
  file.extension != null and file.Ext.entropy >= 7 and
  file.Ext.original.name : ("*.jpg", "*.bmp", "*.png", "*.pdf", "*.doc", "*.docx", "*.xls", "*.xlsx", "*.ppt", "*.pptx") and
  not file.extension : ("tmp", "~tmp", "diff", "gz", "download", "bak", "bck", "lnk", "part", "save", "url", "jpg",
                        "bmp", "png", "pdf", "doc", "docx", "xls", "xlsx", "ppt", "pptx") and
  process.thread.Ext.call_stack_summary :
                     ("ntdll.dll|kernelbase.dll|Unbacked",
                      "ntdll.dll|kernelbase.dll|kernel32.dll|Unbacked",
					  "ntdll.dll|kernelbase.dll|Unknown|kernel32.dll|ntdll.dll",
					  "ntdll.dll|kernelbase.dll|Unknown|kernel32.dll|ntdll.dll",
					  "ntdll.dll|kernelbase.dll|kernel32.dll|Unknown|kernel32.dll|ntdll.dll",
                      "ntdll.dll|wow64.dll|wow64cpu.dll|wow64.dll|ntdll.dll|kernelbase.dll|Unbacked",
                      "ntdll.dll|wow64.dll|wow64cpu.dll|wow64.dll|ntdll.dll|kernelbase.dll|Unbacked|kernel32.dll|ntdll.dll",
                      "ntdll.dll|Unbacked",
                      "Unbacked",
					  "Unknown")]
'''

min_endpoint_version = "8.7.0"
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

[[optional_actions]]
action = "rollback"
field = "process.entity_id"
state = 0

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1486"
name = "Data Encrypted for Impact"
reference = "https://attack.mitre.org/techniques/T1486/"

[[threat.technique]]
id = "T1490"
name = "Inhibit System Recovery"
reference = "https://attack.mitre.org/techniques/T1490/"


[threat.tactic]
id = "TA0040"
name = "Impact"
reference = "https://attack.mitre.org/tactics/TA0040/"

[internal]
min_endpoint_version = "8.7.0"