FollieHiyuki-dotfiles/system/etc/sysctl.d/harden.conf
2021-10-17 21:48:00 +07:00

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# NOTE: THIS IS ONLY A TEMPLATE. CHANGE IT BEFORE APPLYING IT
########## Kernel ##########
# enable ExecShield protection
# 2 enables ExecShield by default unless applications bits are set to disabled
# uncomment on systems without NX/XD protections
# check with: dmesg | grep --color '[NX|DX]*protection'
#kernel.exec-shield = 2
# enable ASLR
# turn on protection and randomize stack, vdso page and mmap + randomize brk base address
kernel.randomize_va_space = 2
# controls the System Request debugging functionality of the kernel
kernel.sysrq = 0
# controls whether core dumps will append the PID to the core filename
# useful for debugging multi-threaded applications
kernel.core_uses_pid = 1
# restrict access to kernel address
# kernel pointers printed using %pK will be replaced with 0s regardless of privileges
kernel.kptr_restrict = 2
# Ptrace protection using Yama
# - 1: only a parent process can be debugged
# - 2: only admins canuse ptrace (CAP_SYS_PTRACE capability required)
# - 3: disables ptrace completely, reboot is required to re-enable ptrace
kernel.yama.ptrace_scope = 3
# restrict kernel logs to root only
kernel.dmesg_restrict = 1
# restrict BPF JIT compiler to root only
kernel.unprivileged_bpf_disabled = 1
# disables kexec as it can be used to livepatch the running kernel
kernel.kexec_load_disabled = 1
# disable unprivileged user namespaces to decrease attack surface
kernel.unprivileged_userns_clone = 0
# allow for more PIDs
# this value can be up to:
# - 32768 (2^15) on a 32-bit system
# - 4194304 (2^22) on a 64-bit system
kernel.pid_max = 4194304
# reboot machine after kernel panic
#kernel.panic = 10
# restrict perf subsystem usage
kernel.perf_event_paranoid = 3
kernel.perf_cpu_time_max_percent = 1
kernel.perf_event_max_sample_rate = 1
########## File System ##########
# disallow core dumping by SUID/SGID programs
fs.suid_dumpable = 0
# protect the creation of hard links
# one of the following conditions must be fulfilled
# - the user can only link to files that he or she owns
# - the user must first have read and write access to a file, that he/she wants to link to
fs.protected_hardlinks = 1
# protect the creation of symbolic links
# one of the following conditions must be fulfilled
# - the process following the symbolic link is the owner of the symbolic link
# - the owner of the directory is also the owner of the symbolic link
fs.protected_symlinks = 1
# enable extended FIFO protection
fs.protected_fifos = 2
# similar to protected_fifos, but it avoids writes to an attacker-controlled regular file
fs.protected_regular = 2
# increase system file descriptor limit
# this value can be up to:
# - 2147483647 (0x7fffffff) on a 32-bit system
# - 9223372036854775807 (0x7fffffffffffffff) on a 64-bit system
# be aware that the Linux kernel documentation suggests that inode-max should be 3-4 times
# larger than this value
fs.file-max = 9223372036854775807
# increase the amount of files that can be watched
# each file watch handle takes 1080 bytes
# up to 540 MiB of memory will be consumed if all 524288 handles are used
fs.inotify.max_user_watches = 524288
########## Virtualization ##########
# do not allow mmap in lower addresses
vm.mmap_min_addr = 65536
# improve mmap ASLR effectness
vm.mmap_rnd_bits=32
vm.mmap_rnd_compat_bits=16
########## Networking ##########
# increase the maximum length of processor input queues
net.core.netdev_max_backlog = 250000
# enable BPF JIT hardening for all users
# this trades off performance, but can mitigate JIT spraying
net.core.bpf_jit_harden = 2
# increase TCP max buffer size setable using setsockopt()
#net.core.rmem_max = 8388608
#net.core.wmem_max = 8388608
#net.core.rmem_default = 8388608
#net.core.wmem_default = 8388608
#net.core.optmem_max = 8388608
########## IPv4 Networking ##########
# enable BBR congestion control
net.ipv4.tcp_congestion_control = bbr
# disallow IPv4 packet forwarding
net.ipv4.ip_forward = 0
# enable SYN cookies for SYN flooding protection
net.ipv4.tcp_syncookies = 1
# number of times SYNACKs for a passive TCP connection attempt will be retransmitted
net.ipv4.tcp_synack_retries = 5
# do not send redirects
net.ipv4.conf.default.send_redirects = 0
net.ipv4.conf.all.send_redirects = 0
# do not accept packets with SRR option
net.ipv4.conf.default.accept_source_route = 0
net.ipv4.conf.all.accept_source_route = 0
# enable reverse path source validation (BCP38)
# refer to RFC1812, RFC2827, and BCP38 (http://www.bcp38.info)
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.all.rp_filter = 1
# log packets with impossible addresses to kernel log
net.ipv4.conf.default.log_martians = 1
net.ipv4.conf.all.log_martians = 1
# do not accept ICMP redirect messages
net.ipv4.conf.default.accept_redirects = 0
net.ipv4.conf.default.secure_redirects = 0
net.ipv4.conf.all.accept_redirects = 0
net.ipv4.conf.all.secure_redirects = 0
# disable sending and receiving of shared media redirects
# this setting overwrites net.ipv4.conf.all.secure_redirects
# refer to RFC1620
net.ipv4.conf.default.shared_media = 0
net.ipv4.conf.all.shared_media = 0
# always use the best local address for announcing local IP via ARP
net.ipv4.conf.default.arp_announce = 2
net.ipv4.conf.all.arp_announce = 2
# reply only if the target IP address is local address configured on the incoming interface
net.ipv4.conf.default.arp_ignore = 1
net.ipv4.conf.all.arp_ignore = 1
# drop Gratuitous ARP frames to prevent ARP poisoning
# this can cause issues when ARP proxies are used in the network
net.ipv4.conf.default.drop_gratuitous_arp = 1
net.ipv4.conf.all.drop_gratuitous_arp = 1
# ignore all ICMP echo requests
#net.ipv4.icmp_echo_ignore_all = 1
# ignore all ICMP echo and timestamp requests sent to broadcast/multicast
net.ipv4.icmp_echo_ignore_broadcasts = 1
# ignore bad ICMP errors
net.ipv4.icmp_ignore_bogus_error_responses = 1
# mitigate TIME-WAIT Assassination hazards in TCP
# refer to RFC1337
net.ipv4.tcp_rfc1337 = 1
# disable TCP window scaling
# this makes the host less susceptible to TCP RST DoS attacks
net.ipv4.tcp_window_scaling = 0
# increase system IP port limits
net.ipv4.ip_local_port_range = 1024 65535
# TCP timestamps could provide protection against wrapped sequence numbers,
# but the host's uptime can be calculated precisely from its timestamps
# it is also possible to differentiate operating systems based on their use of timestamps
# - 0: disable TCP timestamps
# - 1: enable timestamps as defined in RFC1323 and use random offset for
# each connection rather than only using the current time
# - 2: enable timestamps without random offsets
net.ipv4.tcp_timestamps = 0
# enabling SACK can increase the throughput
# but SACK is commonly exploited and rarely used
net.ipv4.tcp_sack = 0
# divide socket buffer evenly between TCP window size and application
net.ipv4.tcp_adv_win_scale = 1
# increase memory thresholds to prevent packet dropping
#net.ipv4.tcp_rmem = 4096 87380 8388608
#net.ipv4.tcp_wmem = 4096 87380 8388608
########## IPv6 Networking ##########
# disallow IPv6 packet forwarding
net.ipv6.conf.default.forwarding = 0
net.ipv6.conf.all.forwarding = 0
# number of Router Solicitations to send until assuming no routers are present
net.ipv6.conf.default.router_solicitations = 0
net.ipv6.conf.all.router_solicitations = 0
# do not accept Router Preference from RA
net.ipv6.conf.default.accept_ra_rtr_pref = 0
net.ipv6.conf.all.accept_ra_rtr_pref = 0
# learn prefix information in router advertisement
net.ipv6.conf.default.accept_ra_pinfo = 0
net.ipv6.conf.all.accept_ra_pinfo = 0
# setting controls whether the system will accept Hop Limit settings from a router advertisement
net.ipv6.conf.default.accept_ra_defrtr = 0
net.ipv6.conf.all.accept_ra_defrtr = 0
# router advertisements can cause the system to assign a global unicast address to an interface
net.ipv6.conf.default.autoconf = 0
net.ipv6.conf.all.autoconf = 0
# number of neighbor solicitations to send out per address
net.ipv6.conf.default.dad_transmits = 0
net.ipv6.conf.all.dad_transmits = 0
# number of global unicast IPv6 addresses can be assigned to each interface
net.ipv6.conf.default.max_addresses = 1
net.ipv6.conf.all.max_addresses = 1
# enable IPv6 Privacy Extensions (RFC3041) and prefer the temporary address
net.ipv6.conf.default.use_tempaddr = 2
net.ipv6.conf.all.use_tempaddr = 2
# ignore IPv6 ICMP redirect messages
net.ipv6.conf.default.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
# do not accept packets with SRR option
net.ipv6.conf.default.accept_source_route = 0
net.ipv6.conf.all.accept_source_route = 0
# ignore all ICMPv6 echo requests
#net.ipv6.icmp.echo_ignore_all = 1
#net.ipv6.icmp.echo_ignore_anycast = 1
#net.ipv6.icmp.echo_ignore_multicast = 1