161 lines
7.4 KiB
Plaintext
161 lines
7.4 KiB
Plaintext
###############################################################################
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# The MIT License
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#
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# Copyright 2012-2014 Jakub Jirutka <jakub@jirutka.cz>.
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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# THE SOFTWARE.
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#
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###############################################################################
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#
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# Basic ip6tables/IPv6 template for an ordinary servers
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#
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# This file is in iptables-restore format. See the man pages for
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# ip6tables-restore(8) and ip6tables-save(8).
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#
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# The following is a set of firewall rules that should be applicable to Linux
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# servers running within departments. It is intended to provide a useful
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# starting point from which to devise a comprehensive firewall policy for
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# a host.
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#
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# Parts 1 and 3 of these rules are the same for each host, whilst part 2 can be
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# populated with rules specific to particular hosts.
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#
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# This template is based on http://jdem.cz/v64a3 from University of Leicester.
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#
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# For the newest version go to https://gist.github.com/jirutka/3742890.
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#
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# @author Jakub Jirutka <jakub@jirutka.cz>
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# @version 1.3.1
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# @date 2014-01-28
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#
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###############################################################################
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# 1. COMMON HEADER #
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# #
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# This section is a generic header that should be suitable for most hosts. #
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###############################################################################
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*filter
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# Base policy
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:INPUT DROP [0:0]
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:FORWARD DROP [0:0]
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:OUTPUT ACCEPT [0:0]
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# Don't attempt to firewall internal traffic on the loopback device.
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-A INPUT -i lo -j ACCEPT
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# Continue connections that are already established or related to an established
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# connection.
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-A INPUT -m conntrack --ctstate RELATED,ESTABLISHED -j ACCEPT
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# Drop non-conforming packets, such as malformed headers, etc.
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-A INPUT -m conntrack --ctstate INVALID -j DROP
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# Block remote packets claiming to be from a loopback address.
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-A INPUT -s ::1/128 ! -i lo -j DROP
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# Chain for preventing SSH brute-force attacks.
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# Permits 10 new connections within 5 minutes from a single host then drops
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# incomming connections from that host. Beyond a burst of 100 connections we
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# log at up 1 attempt per second to prevent filling of logs.
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-N SSHBRUTE
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-A SSHBRUTE -m recent --name SSH --set
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-A SSHBRUTE -m recent --name SSH --update --seconds 300 --hitcount 10 -m limit --limit 1/second --limit-burst 100 -j LOG --log-prefix "ip6tables[SSH-brute]: "
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-A SSHBRUTE -m recent --name SSH --update --seconds 300 --hitcount 10 -j DROP
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-A SSHBRUTE -j ACCEPT
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# Chain for preventing ping flooding - up to 6 pings per second from a single
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# source, again with log limiting. Also prevents us from ICMP REPLY flooding
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# some victim when replying to ICMP ECHO from a spoofed source.
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-N ICMPFLOOD
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-A ICMPFLOOD -m recent --set --name ICMP --rsource
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-A ICMPFLOOD -m recent --update --seconds 1 --hitcount 6 --name ICMP --rsource --rttl -m limit --limit 1/sec --limit-burst 1 -j LOG --log-prefix "ip6tables[ICMP-flood]: "
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-A ICMPFLOOD -m recent --update --seconds 1 --hitcount 6 --name ICMP --rsource --rttl -j DROP
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-A ICMPFLOOD -j ACCEPT
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###############################################################################
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# 2. HOST SPECIFIC RULES #
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# #
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# This section is a good place to enable your host-specific services. #
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###############################################################################
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# Accept HTTP and HTTPS
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#-A INPUT -p tcp -m multiport --dports 80,443 --syn -m conntrack --ctstate NEW -j ACCEPT
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###############################################################################
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# 3. GENERAL RULES #
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# #
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# This section contains general rules that should be suitable for most hosts. #
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###############################################################################
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# Accept worldwide access to SSH and use SSHBRUTE chain for preventing
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# brute-force attacks.
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-A INPUT -p tcp --dport 22 --syn -m conntrack --ctstate NEW -j SSHBRUTE
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# Permit needed ICMP packet types for IPv6 per RFC 4890.
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-A INPUT -p ipv6-icmp --icmpv6-type 1 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 2 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 3 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 4 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 133 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 134 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 135 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 136 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 137 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 141 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 142 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 130 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 131 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 132 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 143 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 148 -j ACCEPT
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-A INPUT -p ipv6-icmp --icmpv6-type 149 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 151 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 152 -j ACCEPT
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-A INPUT -s fe80::/10 -p ipv6-icmp --icmpv6-type 153 -j ACCEPT
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# Permit IMCP echo requests (ping) and use ICMPFLOOD chain for preventing ping
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# flooding.
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-A INPUT -p ipv6-icmp --icmpv6-type 128 -j ICMPFLOOD
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# Do not log packets that are going to ports used by SMB
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# (Samba / Windows Sharing).
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-A INPUT -p udp -m multiport --dports 135,445 -j DROP
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-A INPUT -p udp --dport 137:139 -j DROP
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-A INPUT -p udp --sport 137 --dport 1024:65535 -j DROP
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-A INPUT -p tcp -m multiport --dports 135,139,445 -j DROP
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# Do not log packets that are going to port used by UPnP protocol.
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-A INPUT -p udp --dport 1900 -j DROP
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# Do not log late replies from nameservers.
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-A INPUT -p udp --sport 53 -j DROP
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# Good practise is to explicately reject AUTH traffic so that it fails fast.
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-A INPUT -p tcp --dport 113 --syn -m conntrack --ctstate NEW -j REJECT --reject-with tcp-reset
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# Prevent DOS by filling log files.
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-A INPUT -m limit --limit 1/second --limit-burst 100 -j LOG --log-prefix "ip6tables[DOS]: "
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COMMIT
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