Marc S. Weidner
ae0bd5f3e9
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Signed-off-by: Marc S. Weidner <msw@coresecret.dev>
242 lines
9.3 KiB
Bash
242 lines
9.3 KiB
Bash
#!/bin/bash
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# SPDX-Version: 3.0
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# SPDX-CreationInfo: 2025-10-11; WEIDNER, Marc S.; <msw@coresecret.dev>
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# SPDX-ExternalRef: GIT https://git.coresecret.dev/msw/CISS.debian.live.builder.git
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# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
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# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <msw@coresecret.dev>
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# SPDX-FileType: SOURCE
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# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
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# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
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# SPDX-PackageName: CISS.debian.live.builder
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# SPDX-Security-Contact: security@coresecret.eu
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set -Ceuo pipefail
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printf "\e[95m++++ ++++ ++++ ++++ ++++ ++++ ++ 🧪 '%s' starting ... \e[0m\n" "${0}"
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cd /root
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cp -u /etc/fail2ban/fail2ban.conf /root/.ciss/cdlb/backup/fail2ban.conf.bak
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chmod 0400 /root/.ciss/cdlb/backup/fail2ban.conf.bak
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### https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1024305
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sed -i 's/#allowipv6 = auto/allowipv6 = auto/1' /etc/fail2ban/fail2ban.conf
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mv /etc/fail2ban/jail.d/defaults-debian.conf /root/.ciss/cdlb/backup/defaults-debian.conf.bak
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chmod 0400 /root/.ciss/cdlb/backup/defaults-debian.conf.bak
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cat << EOF >| /etc/fail2ban/jail.d/ciss-default.conf
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# SPDX-Version: 3.0
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# SPDX-CreationInfo: 2025-05-05; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.live.builder.git
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# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
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# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-FileType: SOURCE
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# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
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# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
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# SPDX-PackageName: CISS.debian.live.builder
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# SPDX-Security-Contact: security@coresecret.eu
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[DEFAULT]
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banaction = nftables-multiport
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banaction_allports = nftables-allports
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dbpurgeage = 384d
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# 127.0.0.1/8 - IPv4 loopback range (local host)
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# ::1/128 - IPv6 loopback
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# fe80::/10 - IPv6 link-local (on-link only; NDP/RA/DAD)
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# ff00::/8 - IPv6 multicast (not an unicast host)
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# ::/128 - IPv6 unspecified (all zeros; never a real peer)
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ignoreip = 127.0.0.1/8 ::1/128 fe80::/10 ff00::/8 ::/128 IGNORE_IP_MUST_BE_SET
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usedns = yes
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[recidive]
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enabled = true
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banaction = nftables[type=custom, family=inet, table=f2b-table, chain=f2b-chain, blocktype=drop]
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bantime = 8d
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bantime.increment = true
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bantime.factor = 1
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bantime.maxtime = 128d
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bantime.multipliers = 1 2 4 8 16
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bantime.overalljails = true
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bantime.rndtime = 877s
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filter = recidive
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findtime = 16d
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logpath = /var/log/fail2ban/fail2ban.log*
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maxretry = 2
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### SSH Handling: Foreign IP (not in /etc/hosts.allow): refused to connect: immediate ban [sshd-refused]
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### Jump host mistyped 1-3 times: no ban, only after four attempts [sshd]
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[sshd]
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enabled = true
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backend = systemd
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bantime = 1h
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bantime.increment = true
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bantime.factor = 1
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bantime.maxtime = 16d
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bantime.multipliers = 1 2 4 8 16 32 64 128 256 384
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bantime.overalljails = true
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bantime.rndtime = 877s
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filter = sshd
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findtime = 16m
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maxretry = 4
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mode = aggressive
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port = PORT_MUST_BE_SET
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protocol = tcp
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[sshd-refused]
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enabled = true
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bantime = 1h
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bantime.increment = true
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bantime.factor = 1
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bantime.maxtime = 16d
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bantime.multipliers = 1 2 4 8 16 32 64 128 256 384
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bantime.overalljails = true
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bantime.rndtime = 877s
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filter = ciss-sshd-refused
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findtime = 16m
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logpath = /var/log/auth.log
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maxretry = 1
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port = PORT_MUST_BE_SET
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protocol = tcp
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#
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# CISS aggressive approach:
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# Any valid client communicating with our server should be going directly to the service ports opened in ufw (ssh, 80, ...).
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# Any client touching other ports is treated as malicious and therefore should be blocked access to ALL ports after 1 attempt.
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#
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[ufw]
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enabled = true
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banaction = nftables[type=custom, family=inet, table=f2b-table, chain=f2b-chain, blocktype=drop]
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bantime = 1h
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bantime.increment = true
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bantime.factor = 1
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bantime.maxtime = 16d
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bantime.multipliers = 1 2 4 8 16 32 64 128 256 384
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bantime.overalljails = true
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bantime.rndtime = 877s
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filter = ciss-ufw
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findtime = 16m
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logpath = /var/log/ufw.log
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maxretry = 1
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# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
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EOF
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cat << EOF >| /etc/fail2ban/filter.d/ciss-ufw.conf
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# SPDX-Version: 3.0
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# SPDX-CreationInfo: 2025-10-18; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.live.builder.git
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# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
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# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-FileType: SOURCE
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# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
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# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
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# SPDX-PackageName: CISS.debian.live.builder
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# SPDX-Security-Contact: security@coresecret.eu
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[Definition]
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# Match UFW BLOCK/REJECT with a source IP and *any* port field (SPT or DPT), protocol may be missing.
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failregex = ^.*UFW (?:BLOCK|REJECT).*?\bSRC=<HOST>\b.*?(?:\bDPT=\d+\b|\bSPT=\d+\b).*$
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ignoreregex =
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# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
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EOF
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cat << 'EOF' >| /etc/fail2ban/filter.d/ciss-sshd-refused.conf
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# SPDX-Version: 3.0
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# SPDX-CreationInfo: 2025-10-18; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-ExternalRef: GIT https://cendev.eu/marc.weidner/CISS.2025.debian.live.builder.git
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# SPDX-FileContributor: WEIDNER, Marc S.; Centurion Intelligence Consulting Agency
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# SPDX-FileCopyrightText: 2024-2025; WEIDNER, Marc S.; <cendev@coresecret.eu>
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# SPDX-FileType: SOURCE
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# SPDX-License-Identifier: EUPL-1.2 OR LicenseRef-CCLA-1.0
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# SPDX-LicenseComment: This file is part of the CISS.debian.installer.secure framework.
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# SPDX-PackageName: CISS.debian.live.builder
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# SPDX-Security-Contact: security@coresecret.eu
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[Definition]
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failregex = ^refused connect from \S+ \(<HOST>\)
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# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=conf
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EOF
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###########################################################################################
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# Remarks: hardening of fail2ban systemd #
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###########################################################################################
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# https://wiki.archlinux.org/title/fail2ban#Service_hardening #
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# The CapabilityBoundingSet parameters CAP_DAC_READ_SEARCH will allow Fail2ban full read #
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# access to every directory and file. CAP_NET_ADMIN and CAP_NET_RAW allow Fail2ban to #
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# operate # on any firewall that has a command-line shell interface. By using #
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# ProtectSystem=strict the filesystem hierarchy will only be read-only; ReadWritePaths #
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# allows Fail2ban to have write access on required paths. #
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###########################################################################################
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mkdir -p /etc/systemd/system/fail2ban.service.d
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mkdir -p /var/log/fail2ban
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cat << 'EOF' >| /etc/systemd/system/fail2ban.service.d/override.conf
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[Service]
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PrivateDevices=yes
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PrivateTmp=yes
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ProtectHome=read-only
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ProtectSystem=strict
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ReadWritePaths=-/var/run/fail2ban
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ReadWritePaths=-/var/lib/fail2ban
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ReadWritePaths=-/var/log/fail2ban
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ReadWritePaths=-/var/spool/postfix/maildrop
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ReadWritePaths=-/run/xtables.lock
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CapabilityBoundingSet=CAP_AUDIT_READ CAP_DAC_READ_SEARCH CAP_NET_ADMIN CAP_NET_RAW
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### Added by CISS.debian.live.builder
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ProtectClock=true
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ProtectHostname=true
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EOF
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cat << 'EOF' >> /etc/fail2ban/fail2ban.local
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[Definition]
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logtarget = /var/log/fail2ban/fail2ban.log
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[Database]
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# Keep entries for at least 384 days to cover recidive findtime.
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dbpurgeage = 384d
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EOF
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###########################################################################################
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# Remarks: Logrotate must be updated either #
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###########################################################################################
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cp -a /etc/logrotate.d/fail2ban /root/.ciss/cdlb/backup/fail2ban_logrotate.bak
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cat << EOF >| /etc/logrotate.d/fail2ban
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/var/log/fail2ban/fail2ban.log {
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daily
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rotate 384
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maxage 384
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notifempty
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dateext
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dateyesterday
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compress
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compresscmd /usr/bin/zstd
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compressext .zst
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compressoptions -20
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uncompresscmd /usr/bin/unzstd
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delaycompress
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shred
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missingok
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postrotate
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fail2ban-client flushlogs 1>/dev/null
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endscript
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# If fail2ban runs as non-root it still needs to have write access
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# to logfiles.
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# create 640 fail2ban adm
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create 640 root adm
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}
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EOF
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touch /var/log/fail2ban/fail2ban.log
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chmod 0640 /var/log/fail2ban/fail2ban.log
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printf "\e[92m++++ ++++ ++++ ++++ ++++ ++++ ++ ✅ '%s' applied successfully. \e[0m\n" "${0}"
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exit 0
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# vim: number et ts=2 sw=2 sts=2 ai tw=128 ft=sh
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