defense_evasion_virtualprotect_call_via_nttestalert.toml

[rule]
description = """
Detects calls to the VirtualProtect Windows API to change memory permissions and the call is originating from a thread
pointing to the API NtTestAlert. This may indicate that this call is coming from a pending APC or a sleeping thread.
"""
id = "9906a386-771f-4003-b426-fbe75bdd6e73"
license = "Elastic License v2"
name = "VirtualProtect Call via NtTestAlert"
os_list = ["windows"]
version = "1.0.3"

query = '''
api where 
 process.Ext.api.name : "VirtualProtect" and 
 process.thread.Ext.call_stack_summary : "ntdll.dll*" and 
 _arraysearch(process.thread.Ext.call_stack, $entry, $entry.symbol_info : ("*NtTestAlert*", "*ZwTestAlert*")) and 
 _arraysearch(process.thread.Ext.call_stack, $entry, $entry.symbol_info : "*ProtectVirtualMemory*") and 
 process.thread.Ext.call_stack_summary : ("ntdll.dll", "ntdll.dll|kernelbase.dll|ntdll.dll|Unknown", "ntdll.dll|Unbacked", "ntdll.dll|Unknown")
'''

min_endpoint_version = "8.8.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1036"
name = "Masquerading"
reference = "https://attack.mitre.org/techniques/T1036/"

[[threat.technique]]
id = "T1055"
name = "Process Injection"
reference = "https://attack.mitre.org/techniques/T1055/"


[threat.tactic]
id = "TA0005"
name = "Defense Evasion"
reference = "https://attack.mitre.org/tactics/TA0005/"

[internal]
min_endpoint_version = "8.8.0"