defense_evasion_acl_modification_via_setfacl.toml

[metadata]
bypass_bbr_timing = true
creation_date = "2024/08/23"
integration = ["endpoint", "auditd_manager"]
maturity = "production"
updated_date = "2024/08/23"

[rule]
author = ["Elastic"]
building_block_type = "default"
description = """
This building block rule (BBR) detects Linux Access Control List (ACL) modification via the setfacl command.
"""
from = "now-9m"
index = ["logs-endpoint.events.*", "endgame-*", "auditbeat-*", "logs-auditd_manager.auditd-*"]
language = "eql"
license = "Elastic License v2"
name = "Access Control List Modification via setfacl"
references = ["https://www.uptycs.com/blog/threat-research-report-team/evasive-techniques-used-by-malicious-linux-shell-scripts"]
risk_score = 21
rule_id = "999565a2-fc52-4d72-91e4-ba6712c0377e"
severity = "low"
tags = [
    "Domain: Endpoint",
    "OS: Linux",
    "Use Case: Threat Detection",
    "Tactic: Defense Evasion",
    "Rule Type: BBR",
    "Data Source: Elastic Defend",
    "Data Source: Elastic Endgame",
    "Data Source: Auditd Manager",
]
timestamp_override = "event.ingested"
type = "eql"
query = '''
process where host.os.type == "linux" and event.type == "start" and
event.action in ("exec", "exec_event", "executed", "process_started") and
process.name == "setfacl"
'''

[[rule.threat]]
framework = "MITRE ATT&CK"

[[rule.threat.technique]]
id = "T1222"
name = "File and Directory Permissions Modification"
reference = "https://attack.mitre.org/techniques/T1222/"

[[rule.threat.technique.subtechnique]]
id = "T1222.002"
name = "Linux and Mac File and Directory Permissions Modification"
reference = "https://attack.mitre.org/techniques/T1222/002/"

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