mirror of
https://github.com/tommytran732/Linux-Setup-Scripts
synced 2024-11-14 05:51:34 -05:00
118 lines
4.2 KiB
Plaintext
118 lines
4.2 KiB
Plaintext
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl
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dev.tty.ldisc_autoload = 0
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# https://access.redhat.com/solutions/1985633
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# Seems dangerous.
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fs.binfmt_misc.status = 0
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl-userspace
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# Enable fs.protected sysctls.
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fs.protected_regular = 2
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fs.protected_fifos = 2
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fs.protected_symlinks = 1
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fs.protected_hardlinks = 1
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#core-dumps
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# Disable coredumps.
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# For additional safety, disable coredumps using ulimit and systemd too.
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kernel.core_pattern=|/bin/false
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fs.suid_dumpable = 0
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# Restrict dmesg to CAP_SYS_LOG.
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# https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
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kernel.dmesg_restrict = 1
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# Disable io_uring
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# https://docs.kernel.org/admin-guide/sysctl/kernel.html#io-uring-disabled
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# https://security.googleblog.com/2023/06/learnings-from-kctf-vrps-42-linux.html
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# Note that this will make using Proxmox extremely annoying though, so you might wanna comment this out
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# on a Proxmox node.
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kernel.io_uring_disabled = 2
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# https://www.kernel.org/doc/Documentation/sysctl/kernel.txt
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl-kernel
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# https://kernsec.org/wiki/index.php/Bug_Classes/Kernel_pointer_leak
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# Restrict access to /proc.
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kernel.kptr_restrict = 2
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# Not needed, I don't do livepatching and reboot regularly.
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# On Ubuntu LTS just sed this to be 0 if you use livepatch.
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kernel.kexec_load_disabled = 1
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl
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# Basically, restrict eBPF to CAP_BPF.
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kernel.unprivileged_bpf_disabled = 1
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net.core.bpf_jit_harden = 2
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# Docker running as root do not require unpriv user ns, which is dangerous, so we disabe it.
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kernel.unprivileged_userns_clone = 0
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# Needed for gVisor, which is used on almost all of my servers.
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kernel.yama.ptrace_scope = 1
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl
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# Restrict performance events from unprivileged users as much as possible.
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# We are using 4 here, since Ubuntu supports such a level.
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# Official Linux kernel documentation only says >= so it probably will work.
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kernel.perf_event_paranoid = 4
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl-kernel
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# Disable sysrq.
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kernel.sysrq = 0
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# https://www.stigviewer.com/stig/red_hat_enterprise_linux_6/2020-09-03/finding/V-217911
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# Not running a router here, so no redirects.
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net.ipv4.conf.*.send_redirects = 0
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net.ipv4.conf.*.accept_redirects = 0
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net.ipv6.conf.*.accept_redirects = 0
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# Check if the source of the IP address is reachable through the same interface it came in.
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# Basic IP spoofing mitigation.
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net.ipv4.conf.*.rp_filter = 1
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# Respond to ICMP
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net.ipv4.icmp_echo_ignore_all = 0
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net.ipv6.icmp.echo_ignore_all = 0
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# Ignore Bogus ICMP responses.
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net.ipv4.icmp_ignore_bogus_error_responses = 1
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# Enable IP Forwarding.
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# Almost all of my servers run Docker anyways, and Docker absolutely requires this.
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net.ipv4.ip_forward = 1
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net.ipv6.conf.all.forwarding = 1
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# https://www.stigviewer.com/stig/red_hat_enterprise_linux_6/2016-06-05/finding/V-38537
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# Ignore bogus icmp response.
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net.ipv4.icmp_ignore_bogus_error_responses = 1
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# Protection against time-wait assasination attacks.
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net.ipv4.tcp_rfc1337 = 1
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# Enable SYN cookies.
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# Basic SYN flood mitigation.
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net.ipv4.tcp_syncookies = 1
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# https://access.redhat.com/sites/default/files/attachments/20150325_network_performance_tuning.pdf
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# Make sure TCP timestamp is enabled.
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net.ipv4.tcp_timestamps = 1
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# https://access.redhat.com/sites/default/files/attachments/20150325_network_performance_tuning.pdf
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# Disable TCP SACK.
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# We have good networking :)
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net.ipv4.tcp_sack = 0
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# No SACK, therefore no Duplicated SACK.
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net.ipv4.tcp_dsack = 0
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# Improve ALSR effectiveness for mmap.
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vm.mmap_rnd_bits = 32
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vm.mmap_rnd_compat_bits = 16
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# https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl-kernel
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# Restrict userfaultfd to CAP_SYS_PTRACE.
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# https://bugs.archlinux.org/task/62780
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# Interestingly enough, Arch does not even have userfaultfd in their kernel, so it is
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# probably not used in the real world at all.
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vm.unprivileged_userfaultfd = 0 |