Features

ipsets basierend auf zB: Hostnamen d.h. iptables Freigaben oder Blocks können auf Domain bzw. Hostnamen Ebene durchgeführt werden im Unterschied zu „nativem“ iptables

ipsets basierend auf CIDR Netznotationen

ipsets basierend auf Einzel IPs

Implementierung von http://iplists.firehol.org/ basierend auf ihrem bash Skript (https://github.com/firehol/blocklist-ipsets)

Pi-Hole Minimal für Blacklists pihole-minimal.tar

Voraussetzungen

Minimale Requirements mit update-ipsets.tar auf jeden Fall wird iprange benötigt

Für /usr/share/netfilter-persistent/plugins.d# iptables-scripts.zip , Originalmodule löschen

dnsmasq zum aktualisieren von den Domain/Hostname basierenden IP Sets

zB: auf Debian Stretch:

apt-get install ipset netfilter-persistent iptables iptables-persistent dnsmasq

Anpassungen

Verzeichnisse u. Dateien

Grundsätzlicher Aufbau

root@mrBox-x:/etc/iptables# ls -al /etc/iptables/
total 60
drwxr-x--- 5 root root 4096 Sep 29 11:42 .
drwxr-xr-x 91 root root 4096 Nov 22 10:08 ..
drwxr-x--- 2 root root 4096 Dec 8 2017 ipset-dns.v4
drwxr-x--- 2 root root 4096 Sep 29 11:15 ipset-ips.v4
drwxr-x--- 2 root root 4096 Sep 29 11:28 ipset-networks.v4
-rw-r----- 1 root root 9291 Sep 29 11:42 rules-new.v4
-rw-r----- 1 root root 6353 Dec 8 2017 rules-new.v6
-rw-r----- 1 root root 9291 Sep 29 11:43 rules.v4
-rw-r----- 1 root root 6353 Dec 8 2017 rules.v6
root@mrBox-x:~# ls -al /usr/share/netfilter-persistent/plugins.d/
total 16
drwxr-xr-x 2 root root 4096 Nov 22 10:19 .
drwxr-xr-x 3 root root 4096 Mar 24 2016 ..
-rwx------ 1 root root 3902 Sep 29 11:31 40-ip4tables
-rwx------ 1 root root 2078 Mar 18 2017 60-ip6tables
root@mrBox-x:~# ls -al /usr/local/sbin/update-ipsets/
total 324
drwxr-sr-x 2 root staff 4096 Sep 29 11:29 .
drwxrwsr-x 3 root staff 4096 Sep 29 11:26 ..
-rw-r--r-- 1 root staff 70 May 2 2018 commands.txt
-rw-r--r-- 1 root staff 2095 May 2 2018 functions.common
-rw-r--r-- 1 root staff 2346 May 2 2018 install.config
-rwxr--r-- 1 root staff 310196 May 2 2018 update-ipsets.sh
root@mrBox-x:/etc/cron.d# cat update-ipset
SHELL=/bin/bash
PATH=/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games
*/15 * * * * root /usr/local/sbin/update-ipsets/update-ipsets.sh --silent &> /dev/null

Firewall IPv4 Beispiel :

# Generated by iptables-save v1.4.12 on Mon Oct 14 15:11:00 2013
*raw
:PREROUTING ACCEPT [60:6158]
:OUTPUT ACCEPT [0:0]
-A PREROUTING -i eth0 -s 10.0.0.0/8 -j RETURN
-A PREROUTING -i eth0 -s 192.168.0.0/16 -j RETURN
-A PREROUTING -i eth0 -s 172.16.0.0/12 -j RETURN
-A PREROUTING -i eth0 -m set --match-set firehol_level1 src -m limit --limit 5/sec -j LOG --log-prefix "fw firehol_level1 DROP: " --log-level 7
-A PREROUTING -i eth0 -m set --match-set firehol_level1 src -j DROP
-A PREROUTING -i eth0 -m set --match-set firehol_level2 src -m limit --limit 5/sec -j LOG --log-prefix "fw firehol_level2 DROP: " --log-level 7
-A PREROUTING -i eth0 -m set --match-set firehol_level2 src -j DROP
COMMIT
*nat
:PREROUTING ACCEPT [1:84]
:INPUT ACCEPT [1:84]
:OUTPUT ACCEPT [0:0]
:POSTROUTING ACCEPT [0:0]
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p udp --dport 53 -m limit --limit 5/sec -j LOG --log-prefix "fw DNS REDIRECT: " --log-level 7
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p udp --dport 53 -j REDIRECT --to 53
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p tcp -m tcp --dport 53 -m limit --limit 5/sec -j LOG --log-prefix "fw DNS REDIRECT: " --log-level 7
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p tcp -m tcp --dport 53 -j REDIRECT --to 53
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p tcp -m tcp --dport 80 -m limit --limit 5/sec -j LOG --log-prefix "fw HTTP REDIRECT: " --log-level 7
-A PREROUTING ! -d 192.168.1.1/32 -i br0 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 8081
-A POSTROUTING -o eth0 -j MASQUERADE
COMMIT
# Completed on Mon Oct 14 15:11:00 2013
# Generated by iptables-save v1.4.12 on Mon Oct 14 15:11:00 2013
*mangle
:PREROUTING ACCEPT [348:36659]
:INPUT ACCEPT [348:36659]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [252:78891]
:POSTROUTING ACCEPT [252:78891]
COMMIT
# Completed on Mon Oct 14 15:11:00 2013
# Generated by iptables-save v1.4.12 on Mon Oct 14 15:11:00 2013
*filter
:INPUT DROP [0:0]
:FORWARD DROP [0:0]
:OUTPUT DROP [0:0]
:ALLOW - [0:0]
:EXT-FW - [0:0]
:EXT-INT - [0:0]
:FW-EXT - [0:0]
:FW-INT - [0:0]
:GARBAGE - [0:0]
:INT-EXT - [0:0]
:INT-FW - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth0 -j EXT-FW
-A INPUT -i br0 -j INT-FW
-A INPUT -j GARBAGE
-A INPUT -m limit --limit 5/sec -j LOG --log-prefix "fw INPUT DROP: " --log-level 7
-A INPUT -j DROP
-A FORWARD -i br0 -o eth0 -j INT-EXT
-A FORWARD -i eth0 -o br0 -j EXT-INT
-A FORWARD -j GARBAGE
-A FORWARD -m limit --limit 5/sec -j LOG --log-prefix "fw FORWARD DROP: " --log-level 7
-A FORWARD -j DROP
-A OUTPUT -o lo -j ACCEPT
-A OUTPUT -o eth0 -j FW-EXT
-A OUTPUT -o br0 -j FW-INT
-A OUTPUT -j GARBAGE
-A OUTPUT -m limit --limit 5/sec -j LOG --log-prefix "fw OUTPUT DROP: " --log-level 7
-A OUTPUT -j DROP
-A ALLOW -m limit --limit 5/sec -j LOG --log-prefix "fw ALLOW ACCEPT: " --log-level 7
-A ALLOW -j ACCEPT
-A EXT-FW -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A EXT-FW -p icmp -m icmp --icmp-type 8 -j ALLOW
-A EXT-FW -j GARBAGE
-A EXT-FW -m limit --limit 5/sec -j LOG --log-prefix "fw EXT-FW DROP: " --log-level 7
-A EXT-FW -j DROP
-A EXT-INT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A EXT-INT -j GARBAGE
-A EXT-INT -m limit --limit 5/sec -j LOG --log-prefix "fw EXT-INT DROP: " --log-level 7
-A EXT-INT -j DROP
-A FW-EXT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FW-EXT -p tcp -m tcp --dport 80 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A FW-EXT -p tcp -m tcp --dport 443 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A FW-EXT -p icmp -m icmp --icmp-type 8 -j ALLOW
-A FW-EXT -p udp -m udp --dport 67 -j ALLOW
-A FW-EXT -p tcp -m tcp --dport 587 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A FW-EXT -p udp -m udp --dport 123 -j ALLOW
-A FW-EXT -p udp -m udp --dport 53 -j ALLOW
-A FW-EXT -p tcp -m tcp --dport 53 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A FW-EXT -p udp -m udp --dport 65194 -j ALLOW
-A FW-EXT -m owner --uid-owner proxy -j ALLOW
-A FW-EXT -j GARBAGE
-A FW-EXT -m limit --limit 5/sec -j LOG --log-prefix "fw FW-EXT DROP: " --log-level 7
-A FW-EXT -j DROP
-A FW-INT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A FW-INT -p udp -m udp --dport 68 -j ALLOW
-A FW-INT -p icmp -m icmp --icmp-type 8 -j ALLOW
-A FW-INT -j GARBAGE
-A FW-INT -m limit --limit 5/sec -j LOG --log-prefix "fw FW-INT DROP: " --log-level 7
-A FW-INT -j DROP
-A GARBAGE -d 224.0.0.1/32 -j DROP
-A GARBAGE -d 255.255.255.255/32 -j DROP
-A GARBAGE -d 224.0.0.251/32 -j DROP
-A GARBAGE -p udp -m udp --dport 137 -j DROP
-A GARBAGE -p udp -m udp --dport 138 -j DROP
-A INT-EXT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INT-EXT -p tcp --syn --dport 465 -j ALLOW
-A INT-EXT -p tcp --syn --dport 587 -j ALLOW
-A INT-EXT -p tcp --syn --dport 993 -j ALLOW
-A INT-EXT -p tcp --syn --dport 995 -j ALLOW
-A INT-EXT -p icmp -m icmp --icmp-type 8 -j ALLOW
-A INT-EXT -m limit --limit 5/sec -j LOG --log-prefix "fw INT-EXT DROP: " --log-level 7
-A INT-EXT -j DROP
-A INT-FW -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
-A INT-FW -p tcp -m tcp --dport 8080 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A INT-FW -p tcp -m tcp --dport 8081 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A INT-FW -p tcp -m tcp --dport 53 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A INT-FW -p tcp -m tcp --dport 80 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A INT-FW -p tcp -m tcp --dport 22 --tcp-flags FIN,SYN,RST,ACK SYN -j ALLOW
-A INT-FW -p udp -m udp --dport 53 -j ALLOW
-A INT-FW -p udp -m udp --dport 67 -j ALLOW
-A INT-FW -p icmp -m icmp --icmp-type 8 -j ALLOW
-A INT-FW -p udp -m udp --dport 123 -j ALLOW
-A INT-FW -j GARBAGE
-A INT-FW -m limit --limit 5/sec -j LOG --log-prefix "fw INT-FW DROP: " --log-level 7
-A INT-FW -j DROP
COMMIT
# Completed on Mon Oct 14 15:11:00 2013

Backup Leitung

Wenn der primäre Link offline geht wechsel zum Sekundären

Wenn der primäre Link offline war und „zurück“ kommt wechsel wieder zum Primären

Wenn der primäre Link funktioniert gibt es keine Änderungen

/usr/local/sbin/check_wan_links.sh

#!/bin/bash
# Requirements:
# IF primary link is down switch to secondary link if not already active
# IF primary link is down and comes back switch to primary link
# IF primary link is active and working do nothing
PRIMARY_IP="82.149.97.213"
SECONDARY_IP="192.168.29.2"
PRIMARY_GATEWAY="82.149.97.1"
SECONDARY_GATEWAY="192.168.29.1"
function checkLink()
{
returnCode="1"
/bin/ping -q -c 5 -I $1 8.8.8.8 >/dev/null || /bin/ping -q -c 5 -I $1 1.1.1.1 >/dev/null || /bin/ping -q -c 5 -I $1 9.9.9.9 >/dev/null || returnCode="0"
echo $returnCode
}
function checkCurrentGateway()
{
default=$(/sbin/ip route get 8.8.8.8 | awk '{print $3}')
echo $default
}
function setCurrentGateway()
{
/sbin/ip route change default via $1
echo "Default route changed to: $1"
}
linkPrimary=$(checkLink $PRIMARY_IP);
currentGateway=$(checkCurrentGateway);
#echo "Link Primary: $linkPrimary"
#echo "Current Gateway: $currentGateway"
[[ $linkPrimary == "0" && $currentGateway == $PRIMARY_GATEWAY ]] && setCurrentGateway $SECONDARY_GATEWAY
[[ $linkPrimary == "1" && $currentGateway == $SECONDARY_GATEWAY ]] && setCurrentGateway $PRIMARY_GATEWAY
exit 0

Routing zB: /etc/network/interfaces

#DREI Huawei Modem
auto bond0.29
iface bond0.29 inet static
up ip route add 192.168.29.0/24 dev bond0.29 table lte
up ip route add default via 192.168.29.1 table lte
up ip rule add from 192.168.92.2 lookup lte
address 192.168.29.2
netmask 255.255.255.0
#EXT - kabelsignal AG
auto eth2
iface eth2 inet static
address 82.149.97.213
netmask 255.255.255.0
gateway 82.149.97.1
up ip route add 82.149.97.0/24 dev eth2 table kabsi
up ip route add default via 82.149.97.1 table kabsi
up ip rule add from 82.149.97.213 lookup kabsi

Gäste WLAN

Gäste WLAN , das innerhalb der vorhandenen LAN Infrastruktur durchgereicht werden kann ohne komplexe VLAN Taggings

In Kombination mit zB: openwrt und openvpn möglich + Linux Firewall

Firewall Konfiguration

Wir benötigen eine Bridge und OpenVPN

Verschlüsselung ist nicht notwendig ausschließlich Authentifizierung

DNSMASQ dient als DHCP Server

/etc/dnsmasq.conf

..
dhcp-range=set:wlan,10.0.212.100,10.0.212.200,255.255.255.0,4h
dhcp-option=tag:wlan,6,8.8.8.8,8.8.4.4
dhcp-option=tag:wlan,3,10.0.212.1
..

/etc/network/interfaces

...
#WLAN Guest Interface
auto br-guest
iface br-guest inet manual
pre-up brctl addbr br-guest
pre-up brctl stp br-guest off
pre-up brctl setfd br-guest 0
pre-up ip addr add 10.0.212.1/24 brd + dev br-guest
pre-up ip li set dev br-guest up
...

/etc/openvpn/wlan-guest.conf

dev tap0
dev-type tap
port 65190
proto udp
mode server
management 127.0.0.1 222
cd /etc/openvpn/wlan-guest
cipher none
server 172.24.240.0 255.255.255.0
dh dh2048.pem
ca ca.crt
cert firewall.crt
key firewall.key
status status.log
client-config-dir ccd
topology subnet
tls-server
keepalive 5 15
verb 3
multihome
script-security 2
up /etc/openvpn/wlan-guest/add_tap.sh
multihome

/etc/openvpn/wlan-guest/add_tap.sh

#!/bin/bash
brctl addif br-guest tap0

Access Point Konfiguration

/etc/config/network

Achtung in diesem Fall 2 VLANs die das interne und Gästenetz aufteilen auf entsprechende Ports ( in diesem Fall 841n TP-Link)

config interface 'loopback'
option ifname 'lo'
option proto 'static'
option ipaddr '127.0.0.1'
option netmask '255.0.0.0'
config interface 'guest'
option ifname 'eth1.2'
option type 'bridge'
config interface 'intern'
option ifname 'eth0 eth1.3'
option proto 'dhcp'
option type 'bridge'
config switch
option name 'switch0'
option reset '1'
option enable_vlan '1'
config switch_vlan
option device 'switch0'
option vlan '3'
option ports '0t 2 3'
config switch_vlan
option device 'switch0'
option vlan '2'
option ports '0t 1 4'

/etc/config/wireless

config wifi-device radio0
option type mac80211
option channel auto
option hwmode	11g
option path	'platform/ar934x_wmac'
option htmode	HT20
list ht_capab	LDPC
list ht_capab	SHORT-GI-20
list ht_capab	SHORT-GI-40
list ht_capab	TX-STBC
list ht_capab	RX-STBC1
list ht_capab	DSSS_CCK-40
# REMOVE THIS LINE TO ENABLE WIFI:
option disabled 0
config wifi-iface
option device radio0
option network guest
option mode ap
option ssid SSID_GASTNETZWERK
option encryption psk2
option key PSK_GASTNETZWERK

/etc/openvpn/client.conf

client
dev tap-guest
dev-type tap
cipher none
proto udp
remote firewall 65190
keepalive 5 10
resolv-retry infinite
script-security 2
up /etc/openvpn/client/add_tap.sh
nobind
ca /etc/openvpn/client/ca.crt
cert /etc/openvpn/client/wlanx.crt
key /etc/openvpn/client/wlanx.key
ns-cert-type server
verb 3

/etc/openvpn/client/add_tap.sh

#!/bin/sh
brctl addif br-guest tap-guest

rogue client workstation detection

Getestet mit Debian 9 - apt-get install arpalert

Es soll eine Mail an root geschickt werden wenn ein unbekannter Client dem System hinzugefügt wird und zusätzlich noch wenn möglich ein Port Scan auf den Client durchgeführt werden

grep -v ^# /etc/arpalert/arpalert.conf

maclist file = "/etc/arpalert/maclist.allow"
maclist alert file = "/etc/arpalert/maclist.deny"
maclist leases file = "/var/lib/arpalert/arpalert.leases"
lock file = "/var/run/arpalert.pid"
use syslog = true
log level = 7
user = arpalert
umask = 177
dump packet = false
daemon = false
dump inter = 5
catch only arp = true
interface = "eth1"
action on detect = "/usr/local/sbin/notifyArpalert.sh"
mod on detect = ""
mod config = ""
execution timeout = 10
max alert = 20
dump black list = false
dump white list = false
dump new address = true
mac timeout = 1555200
expire authorized mac addresses = false
max entry = 1000000
anti flood interval = 5
anti flood global = 50
mac vendor file = "/etc/arpalert/oui.txt"
log mac vendor = true
alert mac vendor = true
mod mac vendor = true
log referenced address = false
alert on referenced address = false
mod on referenced address = false
log deny address = true
alert on deny address = true
mod on deny address = true
log new address = true
alert on new address = true
mod on new address = true
log new mac address = true
alert on new mac address = true
mod on new mac address = true
log ip change = true
alert on ip change = false
mod on ip change = true
log mac change = true
alert on mac change = false
mod on mac change = true
log unauth request = true
alert on unauth request = true
mod on unauth request = true
ignore unknown sender = false
ignore me = true
ignore self test = true
unauth ignore time method = 2
log request abus = true
alert on request abus = true
mod on request abus = true
max request = 1000000
log mac error = true
alert on mac error = true
mod on mac error = true
log flood = true
alert on flood	= true
mod on flood = true
log expire mac address = false
alert on expire mac address = false
mod on expire mac address = false

/usr/local/sbin/notifyArpalert.sh

#!/bin/bash
tmp_file=$(mktemp)
ip_address="$2"
mac_address="$1"
params="$3"
ethernet_device="$4"
alert_type="$5"
echo "Possible Intrusion Attempt" > $tmp_file
echo "IP Address: $ip_address" >> $tmp_file
echo "MAC Address: $mac_address" >> $tmp_file
echo "Parameters: $params" >> $tmp_file
echo "Alert Type: $alert_type" >> $tmp_file
alert_explained=$(cat << EOF
Alert Types: \n
0: ip change \n
1: mac address only detected but not in whithe list \n
2: mac address in black list \n
3: new mac address \n
4: unauthorized arp request \n
5: abusive number of arp request detected \n
6: ethernet mac address different from arp mac address \n
7: global flood detection \n
8: new mac adress without ip \n
9: mac change \n
10: mac expire \n
EOF)
echo -e $alert_explained >> $tmp_file
echo "Nmap Scan: " >> $tmp_file
ip route get $ip_address | grep -q eth1
( [[ $? == 0 ]] && nmap -Pn $ip_address >> $tmp_file ) || echo "I'm not performing nmap on $ip_address" >> $tmp_file
cat $tmp_file | mail -s "Possible Break in Attempt " root
rm $tmp_file

/etc/arpalert/maclist.allow

#KOMMENTAR GERÄT1
11:22:33:44:55:66 IP_GERÄT1 INTERFACE_NETZWERK

rogue dhcp server detection

dhcp-probe

- BUG beim Socket WAIT ?? - im Debugging „wartet“ er für immer nach erster Runde

Es sollen DHCP Server gefunden werden , die sich in der aktuellen Broadcast Domain befinden, die nicht autorisiert sind

getestet auf Debian 9 mit apt-get install dhcp-probe

löschen von dhcp-probe init Skript rm /etc/init.d/dhcp-probe

Die Ausgabe wird nun geloggt über syslog mit Systemd

Systemd Unit /lib/systemd/system/dhcp_probe\@.service

[Unit]
Description=DHCP-Probe Instance %i
After=network.target
[Service]
Type=simple
ExecStart=/usr/sbin/dhcp_probe -f -d 11 -T %i
#2020-08-12 cc: ExecStop not defined on purpose
KillSignal=9
[Install]
WantedBy=multi-user.target

Für interface eth1:

ln -s /lib/systemd/system/dhcp_probe\@.service /etc/systemd/system/multi-user.target.wants/dhcp_probe\@eth1.service

/etc/dhcp_probe.cf

legal_server IP_DHCP_SERVER1
legal_server IP_DHCP_SERVER2
alert_program_name2 /usr/local/sbin/notifyDHCP.sh
response_wait_time 10000

/usr/local/sbin/notifyDHCP.sh

#!/bin/bash
tmp_file=$(mktemp)
# -I the name of the interface on which the unexpected response packet was received
# -i the IP source address of the packet
# -m Ethernet source address of the packet
ip_address="NONE"
mac_address="NONE"
ethernet_device="NONE"
program_id="NONE"
while getopts ":I:i:m:p:" arg; do
case "$arg" in
I)
ethernet_device=$OPTARG
;;
i)
ip_address=$OPTARG
;;
m)
mac_address=$OPTARG
;;
p)
program_id=$OPTARG
;;
*)
;;
esac
done
echo "Possible Rogue DHCP Server" > $tmp_file
echo "IP Address: $ip_address" >> $tmp_file
echo "MAC Address: $mac_address" >> $tmp_file
echo "Ethernet Device: $ethernet_device" >> $tmp_file
echo "Nmap Scan: " >> $tmp_file
ip route get $ip_address | grep -q eth1
( [[ $? == 0 ]] && nmap -Pn $ip_address >> $tmp_file ) || echo "I'm not performing nmap on $ip_address" >> $tmp_file
cat $tmp_file | mail -s "POSSIBLE rogue DHCP SERVER " root
rm $tmp_file

dhclient Skript

Getestet unter Debian 9

Wir lassen den offiziellen DHCP Client dhclient eine Lease über das Interface %i zb. eth1 holen und triggern sobald er die IP setzen sollte /usr/local/sbin/triggerDHCPLease.sh Das Renewal setzen wir auf 300 Sekunden /usr/local/sbin/triggerDHCPLease.sh - Wenn die lease von einem DHCP Server kommt , den wir nicht whitelisted haben rufe notfiyDHCP.sh auf scanne ggf. die IP mit nmap und sende ein Mail an root

apt-get install isc-dhcp-client

Systemd Service cat /lib/systemd/system/dhcp-monitoring\@.service

[Unit]
Description=DHCP-Monitoring Instance %i
After=network.target
[Service]
Type=simple
ExecStart=/sbin/dhclient -v -d -sf /usr/local/sbin/triggerDHCPLease.sh -cf /usr/local/etc/dhcp-monitoring/dhclient.conf -lf /dev/zero %i
#2020-08-12 cc: ExecStop not defined on purpose
KillSignal=9
[Install]
WantedBy=multi-user.target

Für Netzwerinterface eth1 starten

ln -s /lib/systemd/system/dhcp-monitoring\@.service /etc/systemd/system/multi-user.target.wants/dhcp-monitoring\@eth1.service

ls -al /etc/systemd/system/multi-user.target.wants/dhcp-monitoring\@eth1.service
lrwxrwxrwx 1 root root 44 Aug 12 13:35 /etc/systemd/system/multi-user.target.wants/dhcp-monitoring@eth1.service -> /lib/systemd/system/dhcp-monitoring@.service

/usr/local/sbin/triggerDHCPLease.sh

#!/bin/bash
WHITELISTED_DHCP_SERVERS="^(IP_DHCP_SERVER_1|IP_DHCP_SERVER2)$"
#2020-08-12 cc: will be triggered from dhclient therefore certain variables have to exist
#Variable new_dhcp_server_identifier must be present
function bailout
{
echo -e "$1"
exit 2
}
[[ -v new_dhcp_server_identifier ]] || bailout "new_dhcp_server_identifier is not set - called by dhclient ? "
echo $new_dhcp_server_identifier | grep -q -P "$WHITELISTED_DHCP_SERVERS"
grepReturn=$?
if [ $grepReturn != "0" ]
then
/usr/local/sbin/notifyDHCP.sh -i $new_dhcp_server_identifier
fi
exit 0

/usr/local/etc/dhcp-monitoring/dhclient.conf

https://stackoverflow.com/questions/29966496/dhclient-override-renewal-time#39931509

# man page for more information about the syntax of this file
# and a more comprehensive list of the parameters understood by
# dhclient.
#
# Normally, if the DHCP server provides reasonable information and does
# not leave anything out (like the domain name, for example), then
# few changes must be made to this file, if any.
#
option rfc3442-classless-static-routes code 121 = array of unsigned integer 8;
send host-name = gethostname();
request subnet-mask, broadcast-address, time-offset, routers,
domain-name, domain-name-servers, domain-search, host-name,
dhcp6.name-servers, dhcp6.domain-search, dhcp6.fqdn, dhcp6.sntp-servers,
netbios-name-servers, netbios-scope, interface-mtu,
rfc3442-classless-static-routes, ntp-servers;
supersede dhcp-rebinding-time 300;
supersede dhcp-lease-time 300;
supersede dhcp-renewal-time 300;

VPN

roadworker mfa - multiple factor auth

Bei OpenVPN mit entsprechender Konfiguration wäre sie implizit gegeben wenn zB: ein Zertifikat zur Authentifizierung benutzt wird + Username + Password

OpenVPN Server - roadworker-auth.conf:

...
auth-user-pass-verify /etc/openvpn/roadworker-auth/hybrid_auth.sh via-env
script-security 3
...

/etc/openvpn/roadworker-auth/hybrid_auth.sh

#!/bin/bash
function bailout ()
{
echo $1
exit 1
}
export username
export password
#env > /tmp/debug
#echo "u: -$AUTH_USERNAME-" >> /tmp/debug
#echo "p: -$AUTH_PASSWORD-" >> /tmp/debug
ORIGINAL_PASSWORD="$password"
AUTH_TOTP_SECRET="/etc/openvpn/roadworker-auth/totp/$username"
echo $username | grep -P -q "^[A-Za-z0-9\.]+$"
#2021-09-21 cc: Somehow malformed
[[ $? != 0 ]] && bailout "Username malformed"
[[ -f $AUTH_TOTP_SECRET && ${#password} -lt 7 ]] && bailout "TOTP is used but password is too small"
#2021-09-21 cc: The last 6 digits contain the TOTP string / the rest is the password
[[ -f $AUTH_TOTP_SECRET ]] && password=$(echo ${ORIGINAL_PASSWORD::-6})
/etc/openvpn/roadworker-auth/smb_auth.sh
RET_SMB_AUTH=$?
[[ ! -f $AUTH_TOTP_SECRET ]] && exit $?
#echo "smb auth: $RET_SMB_AUTH" > /tmp/smb_auth
[[ $RET_SMB_AUTH != 0 ]] && bailout "SMB Auth invalid"
password=$(echo ${ORIGINAL_PASSWORD: -6})
/etc/openvpn/roadworker-auth/totp_auth.sh
exit $?

/etc/openvpn/roadworker-auth/smb_auth.sh

Gültiger Account check via smb check username

AUTH_USERNAME="$username"
AUTH_PASSWORD="$password"
AUTH_SERVER="SERVER_AUTH"
[[ $AUTH_USERNAME == "" || $AUTH_USERNAME == " " ]] && AUTH_USERNAME="---"
[[ $AUTH_PASSWORD == "" || $AUTH_USERNAME == " " ]] && AUTH_PASSWORD="---"
#env > /tmp/debug
#echo "u: -$AUTH_USERNAME-" >> /tmp/debug_smb
#echo "p: -$AUTH_PASSWORD-" >> /tmp/debug_smb
echo $AUTH_PASSWORD | /usr/bin/smbclient -mSMB3 --ip-address=$AUTH_SERVER --list=$AUTH_SERVER --user=$AUTH_USERNAME --timeout=5 &> /dev/null
exit $?

/etc/openvpn/roadworker-auth/totp_auth.sh

TOTP Check mit oathtool

#!/bin/bash
function bailout ()
{
echo $1
exit 1
}
AUTH_USERNAME="$username"
AUTH_PASSWORD="$password"
AUTH_TOTP_SECRET="/etc/openvpn/roadworker-auth/totp/$AUTH_USERNAME"
[[ $AUTH_USERNAME == "" || $AUTH_USERNAME == " " ]] && AUTH_USERNAME="---"
[[ $AUTH_PASSWORD == "" || $AUTH_USERNAME == " " ]] && AUTH_PASSWORD="---"
echo $AUTH_USERNAME | grep -P -q "^[A-Za-z0-9\.]+$"
#2021-09-21 cc: Somehow malformed
[[ $? != 0 ]] && bailout "Username malformed"
#2021-09-21 cc: Somehow not 6 digits
echo $AUTH_PASSWORD | grep -P -q "^[0-9]{6}$"
[[ $? != 0 ]] && bailout "Digits malformed"
#2021-09-21 cc: This is tricky , if there's no secret file - it hasn't been created yet so auth succeeds
[[ ! -f $AUTH_TOTP_SECRET ]] && exit 0
TOTP_SEED=$(cat $AUTH_TOTP_SECRET)
DIGIT_CODE=$(oathtool -b --totp $TOTP_SEED)
#env > /tmp/debug
#echo "u: -$AUTH_USERNAME-" >> /tmp/debug
#echo "p: -$AUTH_PASSWORD-" >> /tmp/debug
#echo "c: -$DIGIT_CODE" >> /tmp/debug
[[ $DIGIT_CODE == $AUTH_PASSWORD ]] && exit 0
exit 1

Um für bestimmten User TOTP zu aktivieren

pwgen -0 -s -1 16 > /etc/openvpn/roadworker-auth/totp/username

Dieser TOTP Seed , der nun unter /etc/openvpn/roadworker-auth/totp/username zB: ABCABCBABCBCDFFG muss dem entsprechenden User sicher übermittelt werden zB: über Signal/Whatsapp - er kann ihn zB: im Google Authenticator als eigenen Eintrag hinzufügen

Variante um bei bestehender zertifikatsbasierender Authentifizierung OTP zu aktivieren:

für bestimmtes Gerät d.h. Zertifikat wird es obligatorisch und User können zum Zertifikat spezifiziert werden

/etc/openvpn/roadworker-cert/roadworker-cert.conf

...
auth-user-pass-verify /etc/openvpn/roadworker-cert/totp_auth.sh via-env
auth-user-pass-optional
script-security 3
....

/etc/openvpn/roadworker-cert/totp_auth.sh

#!/bin/bash
function bailout ()
{
echo $1
echo $1 | logger -t totp
exit 1
}
AUTH_USERNAME="$username"
AUTH_PASSWORD="$password"
AUTH_COMMON_NAME="$common_name"
AUTH_TOTP_ROOT_SECRET="/etc/openvpn/roadworker-cert/totp/"
AUTH_TOTP_SECRET="$AUTH_TOTP_ROOT_SECRET/$AUTH_COMMON_NAME/$AUTH_USERNAME"
#2021-10-14 cc: Certificate required
echo $common_name | grep -P -q "^[A-Za-z0-9\.\-]+$"
[[ $? != 0 ]] && bailout "Common certificate Name malformed"
#2021-10-14 cc: IF directory with common name does not exist OTP is not activated
[[ ! -d "$AUTH_TOTP_ROOT_SECRET/$AUTH_COMMON_NAME" ]] && exit 0
echo $AUTH_USERNAME | grep -P -q "^[A-Za-z0-9\.]+$"
#2021-09-21 cc: Somehow malformed
[[ $? != 0 ]] && bailout "Username malformed"
#2021-09-21 cc: Somehow not 6 digits
echo $AUTH_PASSWORD | grep -P -q "^[0-9]{6}$"
[[ $? != 0 ]] && bailout "Digits malformed"
#2021-09-21 cc: This is tricky , if there's no secret file - it has been created yet so auth succeeds
#2021-10-14 cc: If common_name root path exists there must be a file for the user
[[ ! -f $AUTH_TOTP_SECRET ]] && bailout "TOTP Secret not found - is needed"
TOTP_SEED=$(cat $AUTH_TOTP_SECRET)
DIGIT_CODE=$(oathtool -b --totp $TOTP_SEED)
#env > /tmp/debug
#echo "u: -$AUTH_USERNAME-" >> /tmp/debug
#echo "p: -$AUTH_PASSWORD-" >> /tmp/debug
#echo "c: -$DIGIT_CODE" >> /tmp/debug
[[ $DIGIT_CODE == $AUTH_PASSWORD ]] && exit 0
exit 1

roadworker openvpn wake on lan (wol) trigger

zB: bei Roadworkern die per Remote Desktop auf ihre Bürorechner zugreifen möchten / Die Bürorechner können ruhig heruntergefahren werden / Sobald eine erfolgreiche authentifizierte Verbindung aufgebaut wurde wird wol für den Rechner getriggered

/etc/openvpn/roadworker.conf (getestet auf Debian stretch)

...
script-security 2
client-connect /usr/local/sbin/wake-on-vpn.sh
...

/usr/local/sbin/wake-on-vpn.sh

#!/bin/bash
case "$common_name" in
COMMON_NAME_ROADWORKER)
echo "Wake up Client associated with: $common_name"
/usr/bin/wakeonlan -i IP_BROADCAST TARGET_MAC_ADDRESS | /usr/bin/logger -t roadworker
;;
*)
echo "No Client to wake up found: $common_name" | logger -t roadworker
;;
esac
exit 0

roadworker strongswan ipsec

Auth über radius server / Trigger bei strongswan für wake on lan

Getestet auf: Ubuntu 18.04

/etc/ipsec.conf

Verbindungsparameter wurden speziell auf Windows Rechner ausgerichtet , damit IPSEC VPN im Windows automatisch funktioniert - Achtung bei Windows wird die Default Route ersetzt , muss sich um ein „Feature“ handeln egal ob bei leftsubnet nur das Zielnetz spezifiziert wird

CA Zertifikat muss für den Computer Zertifikatsstore importiert worden sein und FQDN muss matchen bei Verbindungsaufbau mit zB: vpn.firewall.at

# ipsec.conf - strongSwan IPsec configuration file
config setup
#plutostart=no
conn %default
keyexchange=ikev2
ike=aes256-sha1-modp1024!
esp=aes256-sha1!
dpdaction=clear
dpddelay=300s
rekey=no
conn roadworker
left=%any
leftsubnet=0.0.0.0/0
leftauth=pubkey
leftcert=vpn.firewall.at.crt
leftid=@vpn.firweall.at
right=%any
rightsourceip=172.16.3.0/24
rightauth=eap-radius
eap_identity=%identity
rightsendcert=never
auto=add
leftupdown=/usr/local/sbin/wakeup.sh

wake on lan (wol) bei erfolgreichem Login: /usr/local/sbin/wakeup.sh

#!/bin/bash
#Debugging: env > /tmp/env_wakeup
#PLUTO_XAUTH_ID=ACCOUNTNAME@DOMAIN
/usr/sbin/etherwake -i eth1 -b -D MAC_ADDRESS
exit 0

Traffic Shaping - tc

- Großteil „man“ Seiten https://wiki.archlinux.org/title/Advanced_traffic_control / https://tldp.org/en/Traffic-Control-HOWTO/ar01s06.html

- PLAYGROUND - für bestimmten Traffic Bandbreite insgesamt einschränken , damit zB: ein Pool von Adressen eingeschränkt werden kann wie zB: Windows Updates :) entweder über iptables Markierungen oder über ipset Matches

#!/bin/sh -x
# Maximum allowed downlink. Set to 90% of the achievable downlink in mbit
DOWNLINK=60
# Interface facing the Internet
EXTDEV=wlp2s0
# Load IFB, all other modules all loaded automatically
modprobe ifb
ip link set dev ifb0 down
# Clear old queuing disciplines (qdisc) on the interfaces and the MANGLE table
tc qdisc del dev $EXTDEV root 2> /dev/null > /dev/null
tc qdisc del dev $EXTDEV ingress 2> /dev/null > /dev/null
tc qdisc del dev ifb0 root 2> /dev/null > /dev/null
tc qdisc del dev ifb0 ingress 2> /dev/null > /dev/null
iptables -t mangle -F
# appending "stop" (without quotes) after the name of the script stops here.
if [ "$1" = "stop" ]
then
echo "Shaping removed on $EXTDEV."
exit
fi
ip link set dev ifb0 up
# HTB classes on IFB with rate limiting - default class 3:30
tc qdisc add dev ifb0 root handle 3: htb default 30
tc class add dev ifb0 parent 3:3 classid 3:30 htb rate 60mbit ceil 60mbit
tc class add dev ifb0 parent 3:3 classid 3:33 htb rate 10mbit ceil 10mbit
# Packets marked with "2" on IFB flow through class 3:33
tc filter add dev ifb0 parent 3:0 protocol ip handle 2 fw flowid 3:33
# Martin Devera, author of HTB, then recommends SFQ for beneath these classes:
tc qdisc add dev ifb0 parent 3:30 handle 30: sfq perturb 10
tc qdisc add dev ifb0 parent 3:33 handle 33: sfq perturb 10
#https://speed.hetzner.de/1GB.bin
iptables -t mangle -A PREROUTING -s 88.198.248.254 -j MARK --set-mark 2
iptables -t mangle -A PREROUTING -j CONNMARK --save-mark
# Forward all ingress traffic on internet interface to the IFB device
tc qdisc add dev $EXTDEV ingress handle ffff:
tc filter add dev $EXTDEV parent ffff: protocol ip \
u32 match u32 0 0 \
action connmark \
action mirred egress redirect dev ifb0 \
flowid ffff:1
# Kein markieren mehr der Pakete / iptables fällt weg über ipset
# root@mrWhiteGhost:/home/urnilxfgbez/Desktop# ipset create slowdown hash:ip
#root@mrWhiteGhost:/home/urnilxfgbez/Desktop# tc filter add dev ifb0 parent 3:0 protocol ip basic match 'ipset(slowdown src,dst)' flowid 3:33
#
#
#
#
#root@mrWhiteGhost:/tmp# tc -s class show dev ifb0
#class htb 3:33 root prio 0 rate 10Mbit ceil 10Mbit burst 1600b cburst 1600b
# Sent 28375626 bytes 20582 pkt (dropped 0, overlimits 20488 requeues 0)
# backlog 0b 0p requeues 0
# lended: 20582 borrowed: 0 giants: 0
# tokens: -16889 ctokens: -16889
#
#class htb 3:30 root prio 0 rate 60Mbit ceil 60Mbit burst 1590b cburst 1590b
# Sent 1760229 bytes 3364 pkt (dropped 0, overlimits 884 requeues 0)
# backlog 0b 0p requeues 0
# lended: 3364 borrowed: 0 giants: 0
# tokens: 3125 ctokens: 3125
exit 0

GeoIP - iptables matches

Getestet mit Debian Buster - Achtung hier gibt es keine xtables-addons* Pakete mehr / Sukzessive Wechsel zu nftables wird spürbar(er)

Dafür gibt es die Pakete in Debian Bullseye wieder / Die Pakete für bullseye scheinen auch unter Debian Buster zu laufen (xtables-addons-common_3.13-1_amd64.deb/xtables-addons-dkms_3.13-1_all.deb ) testen,testen,testen

Grundsätzliches: iptables -m geoip –help

iptables -m geoip --help
iptables v1.8.2
Usage: iptables -[ACD] chain rule-specification [options]
iptables -I chain [rulenum] rule-specification [options]
iptables -R chain rulenum rule-specification [options]
iptables -D chain rulenum [options]
iptables -[LS] [chain [rulenum]] [options]
iptables -[FZ] [chain] [options]
iptables -[NX] chain
iptables -E old-chain-name new-chain-name
iptables -P chain target [options]
iptables -h (print this help information)
Commands:
Either long or short options are allowed.
--append -A chain	Append to chain
--check -C chain	Check for the existence of a rule
--delete -D chain	Delete matching rule from chain
--delete -D chain rulenum
Delete rule rulenum (1 = first) from chain
--insert -I chain [rulenum]
Insert in chain as rulenum (default 1=first)
--replace -R chain rulenum
Replace rule rulenum (1 = first) in chain
--list -L [chain [rulenum]]
List the rules in a chain or all chains
--list-rules -S [chain [rulenum]]
Print the rules in a chain or all chains
--flush -F [chain]	Delete all rules in chain or all chains
--zero -Z [chain [rulenum]]
Zero counters in chain or all chains
--new -N chain	Create a new user-defined chain
--delete-chain
-X [chain]	Delete a user-defined chain
--policy -P chain target
Change policy on chain to target
--rename-chain
-E old-chain new-chain
Change chain name, (moving any references)
Options:
--ipv4	-4	Nothing (line is ignored by ip6tables-restore)
--ipv6	-6	Error (line is ignored by iptables-restore)
[!] --proto	-p proto	protocol: by number or name, eg. `tcp'
[!] --source	-s address[/mask][...]
source specification
[!] --destination -d address[/mask][...]
destination specification
[!] --in-interface -i input name[+]
network interface name ([+] for wildcard)
--jump	-j target
target for rule (may load target extension)
--goto -g chain
jump to chain with no return
--match	-m match
extended match (may load extension)
--numeric	-n	numeric output of addresses and ports
[!] --out-interface -o output name[+]
network interface name ([+] for wildcard)
--table	-t table	table to manipulate (default: `filter')
--verbose	-v	verbose mode
--wait	-w [seconds]	maximum wait to acquire xtables lock before give up
--wait-interval -W [usecs]	wait time to try to acquire xtables lock
default is 1 second
--line-numbers	print line numbers when listing
--exact	-x	expand numbers (display exact values)
[!] --fragment	-f	match second or further fragments only
--modprobe=<command>	try to insert modules using this command
--set-counters PKTS BYTES	set the counter during insert/append
[!] --version	-V	print package version.
geoip match options:
[!] --src-cc, --source-country country[,country...]
Match packet coming from (one of) the specified country(ies)
[!] --dst-cc, --destination-country country[,country...]
Match packet going to (one of) the specified country(ies)
NOTE: The country is inputed by its ISO3166 code

Datenbank aktualisieren 1x im Monat update-geoip.sh

#!/bin/bash
DST_TEMP_DB="/tmp/dbip-country-lite.csv.gz"
SRC_URL="https://download.db-ip.com/free/dbip-country-lite-$(date +%Y)-$(date +%m).csv.gz"
#Required on Ubuntu 18.04: libtext-csv-xs-perl, libnet-cidr-lite-perl / took xt_geoip_build from ubuntu 20.04
XTABLES_BUILD_SCRIPT="/usr/lib/xtables-addons/xt_geoip_build"
XTABLES_GEOIP_DIRECTORY="/usr/share/xt_geoip"
function bailout
{
>&2 echo -e "$1"
exit 2
}
[[ -f $DST_TEMP_DB ]] && bailout "FAIL: $DST_TEMP_DB already found aborting"
wget -q "$SRC_URL" -O $DST_TEMP_DB || bailout "FAIL: $DST_TEMP_DB cannot be downloaded from $SRC_URL"
gunzip -t $DST_TEMP_DB || bailout "FAIL: Gzip Format failure from $SRC_URL"
[[ -d "$XTABLES_GEOIP_DIRECTORY" ]] || echo "FAIL: could not find Destination: $XTABLES_GEOIP_DIRECTORY"
gunzip -f $DST_TEMP_DB --to-stdout > $XTABLES_GEOIP_DIRECTORY/dbip-country-lite.csv || bailout "FAIL: cannot gunzip file from $SRC_URL"
[[ -x $XTABLES_BUILD_SCRIPT ]] || echo "FAIL: could not find $XTABLES_BUILD_SCRIPT"
$XTABLES_BUILD_SCRIPT -D "$XTABLES_GEOIP_DIRECTORY" -S "$XTABLES_GEOIP_DIRECTORY"
rm $DST_TEMP_DB
exit 0

Achtung /usr/lib/xtables-addons/xt_geoip_build stammt aus dem Ubuntu 20.04 Paket von xtables-addons-common_3.8-2_amd64.deb

Nach 20 Minuten Tests mit iptables matches gabs noch keine panic :)

19 976 LOG all -- * * 0.0.0.0/0 0.0.0.0/0 -m geoip --source-country CN,RS LOG flags 0 level 4

WEB Module

Blocks - IPSET

In Kombination mit dnsmasq und seiner Funktionalität ipsets aktualisieren zu können

www-data muss dnsmasq neu starten können zB: visudo → www-data ALL=(ALL)NOPASSWD:/usr/sbin/service dnsmasq restart / und die entsprechenden Berechtigungen für das Set File besitzen unter /etc/dnsmasq.d/ipset-foo.conf

blocked-ipset.zip

Blocks - Hostnamen

In Kombination mit dnsmasq / um quasi „dns Spoofing“ zu betreiben d.h. das Resolving zu überschreiben für bestimmte Hostnamen

www-data muss dnsmasq neu starten können zB: visudo → www-data ALL=(ALL)NOPASSWD:/usr/sbin/service dnsmasq restart

blocked-addresses.zip

Proxy

Um squid proxy ACLs zu bearbeiten

Achtung www-data braucht sudo Rechte für parse / reload

zB: visudo → www-data ALL=(ALL)NOPASSWD:/usr/sbin/squid3 -k reconfigure, /usr/sbin/squid3 -k parse

proxy.zip

Authorizer

Um nach erfolgter Authentifizierung IP/MACs in ipset einzutragen

authorizer.tar.gz