osquery-defense-kit/detection/persistence/low-fd-socket.sql

-- Find programs where fd0 (stdin), fd1 (stdout), or fd2 (stderr) are connected to a socket
--
-- false positives:
--   * none known
--
-- references:
--   * https://www.deepinstinct.com/blog/bpfdoor-malware-evolves-stealthy-sniffing-backdoor-ups-its-game
--
-- tags: process state
-- platform: posix
SELECT
  pos.protocol,
  pos.pid,
  pos.remote_address,
  pos.local_address,
  pos.local_port,
  pos.remote_port,
  pos.state,
  -- Child
  p0.pid AS p0_pid,
  p0.path AS p0_path,
  p0.name AS p0_name,
  p0.start_time AS p0_start,
  p0.cmdline AS p0_cmd,
  p0.cwd AS p0_cwd,
  p0.cgroup_path AS p0_cgroup,
  p0.euid AS p0_euid,
  p0_hash.sha256 AS p0_sha256,
  -- Parent
  p0.parent AS p1_pid,
  p1.path AS p1_path,
  p1.name AS p1_name,
  p1.start_time AS p1_start,
  p1.euid AS p1_euid,
  p1.cmdline AS p1_cmd,
  p1_hash.sha256 AS p1_sha256,
  -- Grandparent
  p1.parent AS p2_pid,
  p2.name AS p2_name,
  p2.start_time AS p2_start,
  p2.path AS p2_path,
  p2.cmdline AS p2_cmd,
  p2_hash.sha256 AS p2_sha256
FROM
  process_open_sockets pos
  JOIN processes p0 ON pos.pid = p0.pid
  LEFT JOIN hash p0_hash ON p0.path = p0_hash.path
  LEFT JOIN processes p1 ON p0.parent = p1.pid
  LEFT JOIN hash p1_hash ON p1.path = p1_hash.path
  LEFT JOIN processes p2 ON p1.parent = p2.pid
  LEFT JOIN hash p2_hash ON p2.path = p2_hash.path
WHERE
  pos.fd < 3
  AND pos.family != 1
  AND p0.path NOT IN (
    '/Applications/NetSpot.app/Contents/MacOS/NetSpot',
    '/Library/Application Support/Viscosity/viscosity_openvpn',
    '/usr/bin/skopeo',
    '/usr/libexec/bootpd',
    '/usr/libexec/pcp/bin/pmcd',
    '/usr/local/bin/velociraptor'
  )