[Rule Tuning] Suspicious Network Connection via systemd (#5432)

rules/linux/persistence_systemd_netcon.toml

@@ -2,7 +2,7 @@
 creation_date = "2024/02/01"
 integration = ["endpoint"]
 maturity = "production"
-updated_date = "2025/02/04"
+updated_date = "2025/12/09"
 
 [rule]
 author = ["Elastic"]
@@ -61,8 +61,31 @@ type = "eql"
 query = '''
 sequence by host.id with maxspan=5s
   [process where host.os.type == "linux" and event.type == "start" and event.action == "exec" and
-   process.parent.name == "systemd" and process.name in (
-     "python*", "php*", "perl", "ruby", "lua*", "openssl", "nc", "netcat", "ncat", "telnet", "awk"
+   process.parent.name == "systemd" and (
+     process.name in (
+       "openssl", "nc", "ncat", "netcat", "nc.openbsd", "nc.traditional", "socat", "busybox", "mkfifo",
+       "nohup", "setsid", "xterm", "telnet", "awk"
+     ) or
+    (process.name : "python*" and process.args : "-c" and process.args : (
+     "*import*pty*spawn*", "*import*subprocess*call*"
+    )) or
+    (process.name : "perl*" and process.args : "-e" and process.args : "*socket*" and process.args : (
+     "*exec*", "*system*"
+    )) or
+    (process.name : "ruby*" and process.args : ("-e", "-rsocket") and process.args : (
+     "*TCPSocket.new*", "*TCPSocket.open*"
+     )) or
+    (process.name : "lua*" and process.args : "-e" and process.args : "*socket.tcp*" and process.args : (
+     "*io.popen*", "*os.execute*"
+    )) or
+    (process.name : "php*" and process.args : "-r" and process.args : "*fsockopen*" and process.args : "*/bin/*sh*") or 
+    (process.name == "node" and process.args == "-e" and process.args : "*spawn*sh*" and process.args : "*connect*") or
+    (process.name : ("awk", "gawk", "mawk", "nawk") and process.args : "*/inet/tcp/*") or
+    (process.name in ("rvim", "vim", "vimdiff", "rview", "view") and process.args == "-c" and process.args : "*socket*")
+  ) and
+   not (
+     process.args in ("/usr/bin/pg_ctlcluster", "/usr/bin/pveproxy", "/usr/sbin/pveum", "/usr/bin/pveupdate") or
+     process.executable like ("/usr/local/cpanel/*/bin/perl", "/opt/puppetlabs/puppet/bin/ruby")
    )
   ] by process.entity_id
   [network where host.os.type == "linux" and event.action == "connection_attempted" and event.type == "start" and