2023-11-04 10:14:42 +00:00
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{...}: {
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2023-09-19 00:17:43 +00:00
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# All sysctl-s are from https://madaidans-insecurities.github.io/guides/linux-hardening.html#sysctl
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boot.kernel.sysctl = {
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# Kernel self-protection
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"kernel.kptr_restrict" = "2"; # Kernel pointer
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"kernel.dmesg_restrict" = "1"; # restricts dmesg
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"kernel.printk" = "3 3 3 3"; # disable kernel log at boot time
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"kernel.unprivileged_bpf_disabled" = "1"; # eBPF
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"net.core.bpf_jit_harden" = "2"; # eBPF
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"dev.tty.ldisc_autoload" = "0"; # tty
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"vm.unprivileged_userfaultfd" = "0";
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"kernel.kexec_load_disabled" = "1";
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"kernel.sysrq" = "4"; # disable magic sysrq
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#"kernel.unprivileged_userns_clone" = "0"; # does not exist on nixos
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"kernel.perf_event_paranoid" = "3";
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# Network
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"net.ipv4.tcp_syncookies" = "1"; # against SYN flood attacks
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"net.ipv4.tcp_rfc1337" = "1"; # against time-wait assassination
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"net.ipv4.conf.all.rp_filter" = "1"; # against IP spoofing
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"net.ipv4.conf.default.rp_filter" = "1";
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"net.ipv4.conf.all.accept_redirects" = "0";
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2023-11-04 10:14:42 +00:00
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"net.ipv4.conf.default.accept_redirects" = "0"; # disable ICMP redirect acceptance and sending, against MITM
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2023-09-19 00:17:43 +00:00
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"net.ipv4.conf.all.secure_redirects" = "0";
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"net.ipv4.conf.default.secure_redirects" = "0";
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"net.ipv6.conf.all.accept_redirects" = "0";
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"net.ipv6.conf.default.accept_redirects" = "0";
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"net.ipv4.conf.all.send_redirects" = "0";
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"net.ipv4.conf.default.send_redirects" = "0";
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"net.ipv4.icmp_echo_ignore_all" = "1"; # ignore all ICMP req, against smurf attacks
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"net.ipv4.conf.all.accept_source_route" = "0";
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"net.ipv4.conf.default.accept_source_route" = "0";
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"net.ipv6.conf.all.accept_source_route" = "0";
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"net.ipv6.conf.default.accept_source_route" = "0";
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"net.ipv6.conf.all.accept_ra" = "0"; # MITM
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"net.ipv6.conf.default.accept_ra" = "0";
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"net.ipv4.tcp_sack" = "0"; # disable TCP SACK
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"net.ipv4.tcp_dsack" = "0";
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"net.ipv4.tcp_fack" = "0";
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# User Space
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"kernel.yama.ptrace_scope" = "2"; # restricts usage of ptrace
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"vm.mmap_rnd_bits" = "32"; # ASLR
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"vm.mmap_rnd_compat_bits" = "16";
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"fs.protected_symlinks" = "1";
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"fs.protected_hardlinks" = "1";
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"fs.protected_fifos" = "2";
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"fs.protected_regular" = "2";
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};
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2023-11-04 10:14:42 +00:00
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}
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