Detection rules › Elastic

Abnormal Auval Child Process Execution

Source
github.com/elastic/protections-artifacts

Detects the execution of a process that should not be executed by the native auval or auvaltool binaries. This activity may occur after a threat actor loads a malicious audio unit plug-in via auval or auvaltool providing them unsigned code execution in the context of those binaries.

MITRE ATT&CK coverage

Rule body

[rule]
description = """
Detects the execution of a process that should not be executed by the native auval or auvaltool binaries. This activity
may occur after a threat actor loads a malicious audio unit plug-in via auval or auvaltool providing them unsigned code
execution in the context of those binaries.
"""
id = "c851df2d-2400-4d11-8bc1-55a26b41263f"
license = "Elastic License v2"
name = "Abnormal Auval Child Process Execution"
os_list = ["macos"]
reference = ["https://posts.specterops.io/audio-unit-plug-ins-896d3434a882"]
version = "1.0.11"

query = '''
process where event.type == "start" and (process.parent.name in ("auval", "auvaltool") or
 process.Ext.effective_parent.name in ("auval", "auvaltool")) and
 process.name like~ ("curl",
                    "nscurl", 
                    "osascript", 
                    "bash", 
                    "sh", 
                    "zsh", 
                    "python*") and 
 not process.command_line like ("/Applications/Logic Pro X.app/Contents/MacOS/Logic Pro X", "/Applications/Logic Pro.app/Contents/MacOS/Logic Pro") and
 not process.Ext.effective_parent.executable like ("/Applications/Logic Pro X.app/Contents/MacOS/Logic Pro X", "/Applications/Logic Pro.app/Contents/MacOS/Logic Pro")
'''

min_endpoint_version = "8.11.0"
optional_actions = []
[[actions]]
action = "kill_process"
field = "process.entity_id"
state = 0

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

[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1059"
name = "Command and Scripting Interpreter"
reference = "https://attack.mitre.org/techniques/T1059/"
[[threat.technique.subtechnique]]
id = "T1059.004"
name = "Unix Shell"
reference = "https://attack.mitre.org/techniques/T1059/004/"



[threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"

[internal]
min_endpoint_version = "8.11.0"

Stages and Predicates

Stage 1: process

process where event.type == "start" and (process.parent.name in ("auval", "auvaltool") or
 process.Ext.effective_parent.name in ("auval", "auvaltool")) and
 process.name like~ ("curl",
                    "nscurl", 
                    "osascript", 
                    "bash", 
                    "sh", 
                    "zsh", 
                    "python*") and 
 not process.command_line like ("/Applications/Logic Pro X.app/Contents/MacOS/Logic Pro X", "/Applications/Logic Pro.app/Contents/MacOS/Logic Pro") and
 not process.Ext.effective_parent.executable like ("/Applications/Logic Pro X.app/Contents/MacOS/Logic Pro X", "/Applications/Logic Pro.app/Contents/MacOS/Logic Pro")

Exclusions

The rule actively suppresses these predicates.

Indicators

These rows show field, operator, and value matches.