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Rex-1.16.1
⭐ Starred 717 / Rex::Commands::Iptables
Security Advisories (1)
CVE-2026-94140 (2026-10-21)

Rex versions through 1.16.1 for Perl accept an unknown SSH host key for remote rsync transfers because sync hardcodes StrictHostKeyChecking=no. Every remote branch of sync builds its ssh command with that option, for password authentication, for private-key authentication and for the fallback. The ssh options a caller sets through set_openssh_opt reach the OpenSSH transport but not this command, so there is no configuration that restores host key checking for the transfer. An attacker who can redirect the connection before the real host key is known presents their own and the transfer proceeds: under password authentication sync sends the connection password to that server, an upload writes the selected local files to it, and a download writes what it returns to the local destination.

NAME

Rex::Commands::Iptables - Iptable Management Commands

DESCRIPTION

With this Module you can manage basic Iptables rules.

Version <= 1.0: All these functions will not be reported.

Only open_port and close_port are idempotent.

SYNOPSIS

use Rex::Commands::Iptables;

task "firewall", sub {
  iptables_clear;

  open_port 22;
  open_port [22, 80] => {
    dev => "eth0",
  };

  close_port 22 => {
    dev => "eth0",
  };
  close_port "all";

  redirect_port 80 => 10080;
  redirect_port 80 => {
    dev => "eth0",
    to  => 10080,
  };

  default_state_rule;
  default_state_rule dev => "eth0";

  is_nat_gateway;

  iptables t => "nat",
        A => "POSTROUTING",
        o => "eth0",
        j => "MASQUERADE";

  # The 'iptables' function also accepts long options,
  # however, options with dashes need to be quoted
  iptables table => "nat",
        accept          => "POSTROUTING",
        "out-interface" => "eth0",
        jump            => "MASQUERADE";

  # Version of IP can be specified in the first argument
  # of any function: -4 or -6 (defaults to -4)
  iptables_clear -6;

  open_port -6, [22, 80];
  close_port -6, "all";
  redirect_port -6, 80 => 10080;
  default_state_rule -6;

  iptables -6, "flush";
  iptables -6,
        t     => "filter",
        A     => "INPUT",
        i     => "eth0",
        m     => "state",
        state => "RELATED,ESTABLISHED",
        j     => "ACCEPT";
};

EXPORTED FUNCTIONS

open_port($port, $option)

Open a port for inbound connections.

task "firewall", sub {
  open_port 22;
  open_port [22, 80];
  open_port [22, 80],
    dev => "eth1";
};

task "firewall", sub {
 open_port 22,
   dev    => "eth1",
   only_if => "test -f /etc/firewall.managed";
} ;

close_port($port, $option)

Close a port for inbound connections.

task "firewall", sub {
  close_port 22;
  close_port [22, 80];
  close_port [22, 80],
    dev    => "eth0",
    only_if => "test -f /etc/firewall.managed";
};

redirect_port($in_port, $option)

Redirect $in_port to another local port.

task "redirects", sub {
  redirect_port 80 => 10080;
  redirect_port 80 => {
    to  => 10080,
    dev => "eth0",
  };
};

iptables(@params)

Write standard iptable comands.

Note that there is a short form for the iptables --flush option; when you pass the option of -F|"flush" as the only argument, the command iptables -F is run on the connected host. With the two argument form of flush shown in the examples below, the second argument is table you want to flush.

task "firewall", sub {
  iptables t => "nat", A => "POSTROUTING", o => "eth0", j => "MASQUERADE";
  iptables t => "filter", i => "eth0", m => "state", state => "RELATED,ESTABLISHED", j => "ACCEPT";

  # automatically flushes all tables; equivalent to 'iptables -F'
  iptables "flush";
  iptables -F;

  # flush only the "filter" table
  iptables flush => "filter";
  iptables -F => "filter";
};

# Note: options with dashes "-" need to be quoted to escape them from Perl
task "long_form_firewall", sub {
  iptables table => "nat",
       append          => "POSTROUTING",
       "out-interface" => "eth0",
       jump            => "MASQUERADE";
  iptables table => "filter",
       "in-interface" => "eth0",
       match          => "state",
       state          => "RELATED,ESTABLISHED",
       jump           => "ACCEPT";
};

is_nat_gateway

This function creates a NAT gateway for the device the default route points to.

task "make-gateway", sub {
  is_nat_gateway;
  is_nat_gateway -6;
};

default_state_rule(%option)

Set the default state rules for the given device.

task "firewall", sub {
  default_state_rule(dev => "eth0");
};

iptables_list

List all iptables rules.

task "list-iptables", sub {
  print Dumper iptables_list;
  print Dumper iptables_list -6;
};

iptables_clear

Remove all iptables rules.

task "no-firewall", sub {
  iptables_clear;
};