Memory File Descriptor Child Process Execution

[rule]
description = """
This rule detects when a child process is executed from a memory file descriptor (memfd). Attackers may use memfd to
create and execute code directly in memory, bypassing traditional file-based detection mechanisms. The use of memfd for
child process execution is uncommon and may indicate an attempt to evade security controls.
"""
id = "edc713a8-f352-4b12-ba50-b24944dfbd2d"
license = "Elastic License v2"
name = "Memory File Descriptor Child Process Execution"
os_list = ["linux"]
reference = ["https://man7.org/linux/man-pages/man2/memfd_create.2.html"]
version = "1.0.6"

query = '''
process where event.type == "start" and event.action == "exec" and process.parent.executable like "?memfd:*" and
not (
  process.executable in ("/usr/bin/fusermount", "/usr/bin/fusermount3", "/usr/sbin/logrotate") or
  (
    process.working_directory == "/run/nordlayer" and
    process.parent.command_line in (
      "/proc/self/fd/4 -config /etc/nordlayer/config.hcl",
      "/dev/fd/4 -config /etc/nordlayer/config.hcl"
    )
  )
)
'''

min_endpoint_version = "7.15.0"
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 = "T1106"
name = "Native API"
reference = "https://attack.mitre.org/techniques/T1106/"


[threat.tactic]
id = "TA0002"
name = "Execution"
reference = "https://attack.mitre.org/tactics/TA0002/"
[[threat]]
framework = "MITRE ATT&CK"
[[threat.technique]]
id = "T1055"
name = "Process Injection"
reference = "https://attack.mitre.org/techniques/T1055/"
[[threat.technique.subtechnique]]
id = "T1055.009"
name = "Proc Memory"
reference = "https://attack.mitre.org/techniques/T1055/009/"


[[threat.technique]]
id = "T1620"
name = "Reflective Code Loading"
reference = "https://attack.mitre.org/techniques/T1620/"


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

[internal]
min_endpoint_version = "7.15.0"