Suspicious Network Connection via systemd

Detects suspicious network events executed by systemd, potentially indicating persistence through a systemd backdoor. Systemd is a system and service manager for Linux operating systems, used to initialize and manage system processes. Attackers can backdoor systemd for persistence by creating or modifying systemd unit files to execute malicious scripts or commands, or by replacing legitimate systemd binaries with compromised ones, ensuring that their malicious code is automatically executed at system startup or during certain system events.

Rule type: eql

Rule indices:

Severity: medium

Risk score: 47

Runs every: 5m

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References: None

Tags:

Version: 1

Rule authors:

Rule license: Elastic License v2

sequence by host.id with maxspan=5s
  [process where host.os.type == "linux" and event.action == "exec" and event.type == "start" and
   process.parent.name == "systemd" and process.name in (
     "python*", "php*", "perl", "ruby", "lua*", "openssl", "nc", "netcat", "ncat", "telnet", "awk"
   )
  ] by process.entity_id
  [network where host.os.type == "linux" and event.action == "connection_attempted" and event.type == "start"
  ] by process.parent.entity_id