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92 lines
2.8 KiB
ReStructuredText
92 lines
2.8 KiB
ReStructuredText
Using Masscanned
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================
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Dedicated addresses
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~~~~~~~~~~~~~~~~~~~
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Masscanned is designed to handle its own IP addresses, which means
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that the host should not have those addresses configured, and
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Masscanned will answer ``ARP`` requests (or ``ICMPv6`` ``ND`` neighbor
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sollicitations).
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The host may have one or more (``IPv4`` and/or ``IPv6``) addresses configured
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on an interface also used by masscanned, but those addresses must be
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different from those configured to be used by masscanned.
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In that situation (dedicated addresses), just run:
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::
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# masscanned -i <iface> -f <ip_addr_file>
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where ``<ip_addr_file>`` is the path of a text file with one address (``IPv4``
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or ``IPv6``) per line.
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Addresses shared with the host
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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Sometimes it is desirable to have an IP address used by the host
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(*e.g.*, for administration tasks) and by masscanned (to handle all
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other incoming packets).
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Since this is not implemented in masscanned, a tiny hack is needed: we
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are going to run it on a ``veth`` interface.
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For this example, we suppose:
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- The interface is ``eth0``, the address is ``192.168.0.10``.
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- We want masscanned to handle all the traffic except for incoming SSH
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connections on TCP/22 port.
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We create a ``veth`` pair of interfaces, on which we are going to use
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the 0.255.0.0/31 network (which should not be a problem since
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0.0.0.0/8 is reserved as "Current Network"):
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::
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# ip link add to_masscanned type veth peer masscanned
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# ip link set masscanned up
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# ip link set to_masscanned up
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# ip addr add 0.255.0.0/31 dev to_masscanned
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# masscanned -i masscanned
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Masscanned can now be used, but only from the host where it runs:
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::
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# ping -c 1 0.255.0.1
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PING 0.255.0.1 (0.255.0.1) 56(84) octets de données.
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64 octets de 0.255.0.1 : icmp_seq=1 ttl=64 temps=0.442 ms
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--- statistiques ping 0.255.0.1 ---
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1 paquets transmis, 1 reçus, 0% packet loss, time 0ms
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rtt min/avg/max/mdev = 0.442/0.442/0.442/0.000 ms
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Now, we are going to use Netfilter / ``iptables`` to redirect incoming
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traffic to masscanned:
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::
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# sysctl -w net.ipv4.ip_forward=1
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# iptables -t nat -A PREROUTING -i eth0 -d 192.168.0.10 -p tcp --dport 22 -j ACCEPT
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# iptables -t nat -A PREROUTING -i eth0 -d 192.168.0.10/32 -j DNAT --to-destination 0.255.0.1
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And, from another host on the 192.168.0.0/24 network:
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::
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# ping -c 1 192.168.0.10
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PING 192.168.0.10 (192.168.0.10) 56(84) octets de données.
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64 octets de 192.168.0.10 : icmp_seq=1 ttl=63 temps=0.366 ms
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--- statistiques ping 192.168.0.10 ---
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1 paquets transmis, 1 reçus, 0% packet loss, time 0ms
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rtt min/avg/max/mdev = 0.366/0.366/0.366/0.000 ms
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The masscanned output:
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::
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WARN - ARP-Reply to ea:c0:d6:20:0c:6a for IP 0.255.0.1
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WARN - ICMP-Echo-Reply to ICMP-Echo-Request
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