mirror of
https://github.com/Kicksecure/security-misc.git
synced 2024-12-22 16:33:35 +07:00
Merge remote-tracking branch 'github-kicksecure/master'
This commit is contained in:
Patrick Schleizer
commit
3135a03e21
16
README.md
16
README.md
@ -37,11 +37,11 @@ Kernel space:
|
||||
- Entirely disable the SysRq key so that the Secure Attention Key (SAK)
|
||||
can no longer be utilized. See [documentation](https://www.kicksecure.com/wiki/SysRq).
|
||||
|
||||
- Optional - Disable all use of user namespaces.
|
||||
|
||||
- Optional - Restrict user namespaces to `CAP_SYS_ADMIN` as they can lead to substantial
|
||||
privilege escalation.
|
||||
|
||||
- Optional - Disable all use of user namespaces.
|
||||
|
||||
- Restrict kernel profiling and the performance events system to `CAP_PERFMON`.
|
||||
|
||||
- Force the kernel to panic on both "oopses", which can potentially indicate and thwart
|
||||
@ -102,6 +102,18 @@ Networking:
|
||||
- Disable ICMP redirect acceptance and redirect sending messages to prevent
|
||||
man-in-the-middle attacks and minimize information disclosure.
|
||||
|
||||
- Optional - Deny sending and receiving shared media redirects to reduce
|
||||
the risk of IP spoofing attacks.
|
||||
|
||||
- Optional - Enable ARP filtering to mitigate some ARP spoofing and ARP
|
||||
cache poisoning attacks.
|
||||
|
||||
- Optional - Respond to ARP requests only if the target IP address is
|
||||
on-link, preventing some IP spoofing attacks.
|
||||
|
||||
- Optional - Drop gratuitous ARP packets to prevent ARP cache poisoning
|
||||
via man-in-the-middle and denial-of-service attacks.
|
||||
|
||||
- Ignore ICMP echo requests to prevent clock fingerprinting and Smurf attacks.
|
||||
|
||||
- Ignore bogus ICMP error responses.
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||||
|
||||
@ -8,6 +8,7 @@
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||||
## If there is no explicit KSPP compliance notice, the setting is not mentioned by the KSPP.
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||||
|
||||
## Enable known mitigations for CPU vulnerabilities.
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||||
## Note, the mitigations for SSB and Retbleed are not currently mentioned in the first link.
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/index.html
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
|
||||
## https://forums.whonix.org/t/should-all-kernel-patches-for-cpu-bugs-be-unconditionally-enabled-vs-performance-vs-applicability/7647
|
||||
@ -17,7 +18,7 @@
|
||||
## https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/advisory-guidance.html
|
||||
## https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/disclosure-documentation.html
|
||||
|
||||
## Enable a subset of known mitigations for CPU vulnerabilities and disable SMT.
|
||||
## Enable a subset of known mitigations for some CPU vulnerabilities and disable SMT.
|
||||
##
|
||||
## KSPP=yes
|
||||
## KSPP sets the kernel parameters.
|
||||
@ -27,7 +28,7 @@ GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX mitigations=auto,nosmt"
|
||||
## Disable SMT as it has been the cause of and amplified numerous CPU exploits.
|
||||
## The only full mitigation of cross-HT attacks is to disable SMT.
|
||||
## Disabling will significantly decrease system performance on multi-threaded tasks.
|
||||
## To enable SMT, remove this line and all other occurrences of "nosmt" in this file.
|
||||
## Note, this setting will prevent re-enabling SMT via the sysfs interface.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/core-scheduling.html
|
||||
## https://forums.whonix.org/t/should-all-kernel-patches-for-cpu-bugs-be-unconditionally-enabled-vs-performance-vs-applicability/7647/17
|
||||
@ -36,95 +37,136 @@ GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX mitigations=auto,nosmt"
|
||||
## KSPP=yes
|
||||
## KSPP sets the kernel parameter.
|
||||
##
|
||||
## To re-enable SMT:
|
||||
## - Remove "nosmt=force".
|
||||
## - Remove all occurrences of ",nosmt" in this file (note the comma ",").
|
||||
## - Downgrade "l1tf=full,force" protection to "l1tf=flush".
|
||||
## - Regenerate the dracut initramfs and then reboot system.
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX nosmt=force"
|
||||
|
||||
## Enable mitigations for both Spectre Variant 2 (indirect branch speculation)
|
||||
## and Intel branch history injection (BHI) vulnerabilities.
|
||||
## Spectre Side Channels (BTI and BHI):
|
||||
## Unconditionally enable mitigation for Spectre Variant 2 (branch target injection).
|
||||
## Enable mitigation for the Intel branch history injection vulnerability.
|
||||
## Currently affects both AMD and Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/spectre.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX spectre_v2=on"
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX spectre_bhi=on"
|
||||
|
||||
## Disable Speculative Store Bypass (Spectre Variant 4).
|
||||
## Unconditionally enable mitigation for both kernel and userspace.
|
||||
## Speculative Store Bypass (SSB):
|
||||
## Mitigate Spectre Variant 4 by disabling speculative store bypass system-wide.
|
||||
## Unconditionally enable the mitigation for both kernel and userspace.
|
||||
## Currently affects both AMD and Intel CPUs.
|
||||
##
|
||||
## https://en.wikipedia.org/wiki/Speculative_Store_Bypass
|
||||
## https://www.suse.com/support/kb/doc/?id=000019189
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX spec_store_bypass_disable=on"
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX ssbd=force-on"
|
||||
|
||||
## Enable mitigations for the L1TF vulnerability through disabling SMT
|
||||
## and L1D flush runtime control.
|
||||
## L1 Terminal Fault (L1TF):
|
||||
## Mitigate the vulnerability by disabling L1D flush runtime control and SMT.
|
||||
## If L1D flushing is conditional, mitigate the vulnerability for certain KVM hypervisor configurations.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX l1tf=full,force"
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX kvm-intel.vmentry_l1d_flush=always"
|
||||
|
||||
## Enable mitigations for the MDS vulnerability through clearing buffer cache
|
||||
## and disabling SMT.
|
||||
## Microarchitectural Data Sampling (MDS):
|
||||
## Mitigate the vulnerability by clearing the CPU buffer cache and disabling SMT.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/mds.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX mds=full,nosmt"
|
||||
|
||||
## Patches the TAA vulnerability by disabling TSX and enables mitigations using
|
||||
## TSX Async Abort along with disabling SMT.
|
||||
## TSX Asynchronous Abort (TAA):
|
||||
## Mitigate the vulnerability by disabling TSX.
|
||||
## If TSX is enabled, clear CPU buffer rings on transitions and disable SMT.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/tsx_async_abort.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX tsx=off"
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX tsx_async_abort=full,nosmt"
|
||||
|
||||
## Mark all huge pages in the EPT as non-executable to mitigate iTLB multihit.
|
||||
## iTLB Multihit:
|
||||
## Mitigate the vulnerability by marking all huge pages in the EPT as non-executable.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/multihit.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX kvm.nx_huge_pages=force"
|
||||
|
||||
## Mitigations for SRBDS to prevent MDS attacks on RDRAND and RDSEED instructions
|
||||
## are only possible through microcode updates from Intel.
|
||||
## Special Register Buffer Data Sampling (SRBDS):
|
||||
## Mitigation of the vulnerability is only possible via microcode update from Intel.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/special-register-buffer-data-sampling.html
|
||||
## https://access.redhat.com/solutions/5142691
|
||||
|
||||
## Enable the prctl() interface to prevent leaks from L1D on context switches.
|
||||
## L1D Flushing:
|
||||
## Mitigate leaks from the L1D cache on context switches by enabling the prctl() interface.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1d_flush.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX l1d_flush=on"
|
||||
|
||||
## Mitigate numerous MMIO Stale Data vulnerabilities and disable SMT.
|
||||
## Processor MMIO Stale Data:
|
||||
## Mitigate the vulnerabilities by appropriately clearing the CPU buffer and disabling SMT.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/processor_mmio_stale_data.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX mmio_stale_data=full,nosmt"
|
||||
|
||||
## Enable mitigations for RETBleed (Arbitrary Speculative Code Execution with
|
||||
## Return Instructions) vulnerability and disable SMT.
|
||||
## Arbitrary Speculative Code Execution with Return Instructions (Retbleed):
|
||||
## Mitigate the vulnerability through CPU-dependent implementation and disable SMT.
|
||||
## Currently affects both AMD Zen 1-2 and Intel CPUs.
|
||||
##
|
||||
## https://en.wikipedia.org/wiki/Retbleed
|
||||
## https://comsec.ethz.ch/research/microarch/retbleed/
|
||||
## https://www.suse.com/support/kb/doc/?id=000020693
|
||||
## https://access.redhat.com/solutions/retbleed
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX retbleed=auto,nosmt"
|
||||
|
||||
## Control RAS overflow mitigation on AMD Zen CPUs.
|
||||
## Cross-Thread Return Address Predictions:
|
||||
## Mitigate the vulnerability for certain KVM hypervisor configurations.
|
||||
## Currently affects AMD Zen 1-2 CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/cross-thread-rsb.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX kvm.mitigate_smt_rsb=1"
|
||||
|
||||
## Speculative Return Stack Overflow (SRSO):
|
||||
## Mitigate the vulnerability by ensuring all RET instructions speculate to a controlled location.
|
||||
## Currently affects AMD Zen 1-4 CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/srso.html
|
||||
##
|
||||
## The default kernel setting will be utilized until provided sufficient evidence to modify.
|
||||
## Using "spec_rstack_overflow=ipbp" may provide stronger security at a greater performance impact.
|
||||
##
|
||||
#GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX spec_rstack_overflow=safe-ret"
|
||||
|
||||
## Enable Gather Data Sampling (GDS) mitigation.
|
||||
## Note for systems that have not received a suitable microcode update this will
|
||||
## entirely disable use of the AVX instructions set.
|
||||
## Gather Data Sampling (GDS):
|
||||
## Mitigate the vulnerability either via microcode update or by disabling AVX.
|
||||
## Note, without a suitable microcode update, this will entirely disable use of the AVX instructions set.
|
||||
## Currently affects Intel CPUs.
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/gather_data_sampling.html
|
||||
##
|
||||
GRUB_CMDLINE_LINUX="$GRUB_CMDLINE_LINUX gather_data_sampling=force"
|
||||
|
||||
## Enable Register File Data Sampling (RFDS) mitigation on Intel Atom CPUs which
|
||||
## encompasses E-cores on hybrid architectures.
|
||||
## Register File Data Sampling (RFDS):
|
||||
## Mitigate the vulnerability by appropriately clearing the CPU buffer.
|
||||
## Currently affects Intel Atom CPUs (which encompasses E-cores on hybrid architectures).
|
||||
##
|
||||
## https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/reg-file-data-sampling.html
|
||||
##
|
||||
|
||||
@ -7,10 +7,15 @@
|
||||
## KSPP=no: not (currently) compliant with recommendations by the KSPP
|
||||
## If there is no explicit KSPP compliance notice, the setting is not mentioned by the KSPP.
|
||||
|
||||
## Disable access to single-user mode (i.e. recovery mode).
|
||||
## Disable access to single-user (recovery) mode.
|
||||
##
|
||||
## https://forums.kicksecure.com/t/remove-linux-recovery-mode-boot-option-from-default-grub-boot-menu/727
|
||||
GRUB_DISABLE_RECOVERY='true'
|
||||
##
|
||||
GRUB_DISABLE_RECOVERY="true"
|
||||
|
||||
## Disable access to Dracut's recovery console.
|
||||
##
|
||||
## https://forums.kicksecure.com/t/harden-dracut-initramfs-generator-by-disabling-recovery-console/724
|
||||
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT rd.shell=0 rd.emergency=halt"
|
||||
##
|
||||
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT rd.emergency=halt"
|
||||
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT rd.shell=0"
|
||||
@ -117,42 +117,41 @@ vm.unprivileged_userfaultfd=0
|
||||
##
|
||||
kernel.sysrq=0
|
||||
|
||||
## Restrict user namespaces to users with CAP_SYS_ADMIN.
|
||||
## Disable user namespaces entirely.
|
||||
## User namespaces aim to improve sandboxing and accessibility for unprivileged users.
|
||||
## Unprivileged user namespaces pose substantial privilege escalation risks.
|
||||
## Restricting may lead to breakages in numerous software packages.
|
||||
##
|
||||
## Flatpak requires unprivileged users to create new user namespaces for sandboxing.
|
||||
## https://github.com/flatpak/flatpak/wiki/User-namespace-requirements
|
||||
## https://salsa.debian.org/debian/bubblewrap/-/blob/debian/latest/debian/README.Debian
|
||||
## https://forums.kicksecure.com/t/can-not-run-flatpak-apps-after-kicksecure-update/592
|
||||
##
|
||||
## Disabling entirely will reduce compatibility with some AppArmor profiles.
|
||||
## Disabling entirely is known to break the UPower systemd service.
|
||||
##
|
||||
## Also breaks (some?) AppImages.
|
||||
## https://forums.kicksecure.com/t/cannot-run-some-appimage-apps-after-kicksecure-upate/594
|
||||
##
|
||||
## Might also break evolution (e-mail client):
|
||||
## https://forums.kicksecure.com/t/impossible-to-start-evolution-app-since-the-last-update/601
|
||||
## Not recommended due to well-known breakages across numerous software packages.
|
||||
##
|
||||
## https://lwn.net/Articles/673597/
|
||||
## https://madaidans-insecurities.github.io/linux.html#kernel
|
||||
## https://gitlab.com/apparmor/apparmor/-/wikis/unprivileged_userns_restriction
|
||||
## https://github.com/a13xp0p0v/kernel-hardening-checker#questions-and-answers
|
||||
## https://github.com/NixOS/nixpkgs/pull/84522#issuecomment-614640601
|
||||
## https://github.com/flatpak/flatpak/wiki/User-namespace-requirements
|
||||
## https://github.com/Kicksecure/security-misc/pull/263
|
||||
## https://github.com/Kicksecure/security-misc/issues/274
|
||||
##
|
||||
## KSPP=no
|
||||
## KSPP sets user.max_user_namespaces=0 sysctl, a Linux mainline, stricter setting.
|
||||
## KSPP sets the sysctl.
|
||||
##
|
||||
## kernel.unprivileged_userns_clone is a Debian specific kernel feature. Not Linux mainline.
|
||||
#kernel.unprivileged_userns_clone=0
|
||||
## Uncomment the following sysctl to entirely disable user namespaces.
|
||||
#user.max_user_namespaces=0
|
||||
|
||||
## Restrict user namespaces to users with CAP_SYS_ADMIN.
|
||||
## See the user.max_user_namespaces setting for more details.
|
||||
## This is a Debian-specific kernel feature, not a Linux mainline setting.
|
||||
## Unprivileged user namespaces pose substantial privilege escalation risks.
|
||||
## Flatpak requires unprivileged users to create new user namespaces for sandboxing.
|
||||
## Restricting is known to cause breakages in some AppImages and the Evolution Email Client.
|
||||
## Not recommended due to widespread breakages across many software packages.
|
||||
##
|
||||
## https://salsa.debian.org/debian/bubblewrap/-/blob/debian/latest/debian/README.Debian
|
||||
## https://gitlab.com/apparmor/apparmor/-/wikis/unprivileged_userns_restriction
|
||||
## https://github.com/flatpak/flatpak/wiki/User-namespace-requirements
|
||||
## https://forums.kicksecure.com/t/can-not-run-flatpak-apps-after-kicksecure-update/592
|
||||
## https://forums.kicksecure.com/t/cannot-run-some-appimage-apps-after-kicksecure-upate/594
|
||||
## https://forums.kicksecure.com/t/impossible-to-start-evolution-app-since-the-last-update/601
|
||||
## https://github.com/Kicksecure/security-misc/issues/274
|
||||
##
|
||||
#kernel.unprivileged_userns_clone=0
|
||||
|
||||
## Restricts kernel profiling to users with CAP_PERFMON.
|
||||
## The performance events system should not be accessible by unprivileged users.
|
||||
## Other distributions such as Ubuntu and Fedora may permit further restricting.
|
||||
@ -281,7 +280,7 @@ fs.protected_fifos=2
|
||||
fs.protected_regular=2
|
||||
|
||||
## Enable ASLR for mmap base, stack, VDSO pages, and heap.
|
||||
## Forces shared libraries to be loaded to random addresses
|
||||
## Forces shared libraries to be loaded to random addresses.
|
||||
## Start location of PIE-linked binaries is randomized.
|
||||
## Heap randomization can lead to breakages with legacy applications.
|
||||
##
|
||||
@ -443,6 +442,48 @@ net.ipv4.conf.*.send_redirects=0
|
||||
net.ipv6.conf.*.accept_redirects=0
|
||||
#net.ipv4.conf.*.secure_redirects=1
|
||||
|
||||
## Deny sending and receiving RFC1620 shared media redirects.
|
||||
## Relevant mainly for network interfaces that operate over shared media such as Ethernet hubs.
|
||||
## Stops the kernel from sending ICMP redirects to specific networks from the connected network.
|
||||
## This variable overrides the use secure_redirects.
|
||||
##
|
||||
## https://cyber.gouv.fr/sites/default/files/document/linux_configuration-en-v2.pdf
|
||||
## https://datatracker.ietf.org/doc/html/rfc1620
|
||||
## https://www.frozentux.net/ipsysctl-tutorial/chunkyhtml/theconfvariables.html
|
||||
##
|
||||
#net.ipv4.conf.*.shared_media=0
|
||||
|
||||
## Enable ARP (Address Resolution Protocol) filtering.
|
||||
## Prevents the Linux kernel from handling the ARP table globally
|
||||
## Can mitigate some ARP spoofing and ARP cache poisoning attacks.
|
||||
## Improper filtering can lead to increased ARP traffic and inadvertently block legitimate ARP requests.
|
||||
##
|
||||
## https://cyber.gouv.fr/sites/default/files/document/linux_configuration-en-v2.pdf
|
||||
##
|
||||
#net.ipv4.conf.*.arp_filter=1
|
||||
|
||||
## Respond to ARP (Address Resolution Protocol) requests only if the target IP address is on-link.
|
||||
## Reduces IP spoofing attacks by limiting the scope of allowable ARP responses.
|
||||
##
|
||||
## https://cyber.gouv.fr/sites/default/files/document/linux_configuration-en-v2.pdf
|
||||
## https://github.com/mullvad/mullvadvpn-app/blob/main/audits/2024-12-10-X41-D-Sec.md#mllvd-cr-24-03-virtual-ip-address-of-tunnel-device-leaks-to-network-adjacent-participant-severity-medium
|
||||
## https://github.com/mullvad/mullvadvpn-app/pull/7141
|
||||
## https://www.x41-dsec.de/static/reports/X41-Mullvad-Audit-Public-Report-2024-12-10.pdf
|
||||
##
|
||||
#net.ipv4.conf.*.arp_ignore=2
|
||||
|
||||
## Drop gratuitous ARP (Address Resolution Protocol) packets.
|
||||
## Stops ARP responses sent by a device without being explicitly requested.
|
||||
## Prevents ARP cache poisoning by rejecting fake ARP entries into a network.
|
||||
## Prevents man-in-the-middle and denial-of-service attacks.
|
||||
## May cause breakages when ARP proxies are used in the network.
|
||||
##
|
||||
## https://cyber.gouv.fr/sites/default/files/document/linux_configuration-en-v2.pdf
|
||||
## https://patchwork.ozlabs.org/project/netdev/patch/1428652454-1224-3-git-send-email-johannes@sipsolutions.net/
|
||||
## https://www.practicalnetworking.net/series/arp/gratuitous-arp/
|
||||
##
|
||||
#net.ipv4.conf.*.drop_gratuitous_arp=1
|
||||
|
||||
## Ignore ICMP echo requests.
|
||||
## Prevents clock fingerprinting through ICMP timestamps and Smurf attacks.
|
||||
##
|
||||
|
||||
Loading…
Reference in New Issue
Block a user