Guide to the Secure Configuration of Red Hat Enterprise Linux 9
Rules, Groups, and Values defined within the XCCDF Benchmark
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Configure Speculative Store Bypass Mitigation
Certain CPUs are vulnerable to an exploit against a common wide industry wide performance optimization known as Speculative Store Bypass (SSB). In...Rule Medium Severity -
Set the Boot Loader Admin Username to a Non-Default Value
The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings. <br><br> To maximize the prote...Rule High Severity -
Enforce Spectre v2 mitigation
Spectre V2 is an indirect branch poisoning attack that can lead to data leakage. An exploit for Spectre V2 tricks the indirect branch predictor int...Rule High Severity -
Ensure debug-shell service is not enabled during boot
systemd's <code>debug-shell</code> service is intended to diagnose systemd related boot issues with various <code>systemctl</code> commands. Once e...Rule Medium Severity -
Disable vsyscalls
To disable use of virtual syscalls, add the argument <code>vsyscall=none</code> to the default GRUB 2 command line for the Linux operating system. ...Rule Medium Severity -
Non-UEFI GRUB2 bootloader configuration
Non-UEFI GRUB2 bootloader configurationGroup -
Verify /boot/grub2/grub.cfg Group Ownership
The file <code>/boot/grub2/grub.cfg</code> should be group-owned by the <code>root</code> group to prevent destruction or modification of the file....Rule Medium Severity -
Verify /boot/grub2/user.cfg Group Ownership
The file <code>/boot/grub2/user.cfg</code> should be group-owned by the <code>root</code> group to prevent reading or modification of the file. To...Rule Medium Severity -
Verify /boot/grub2/grub.cfg User Ownership
The file <code>/boot/grub2/grub.cfg</code> should be owned by the <code>root</code> user to prevent destruction or modification of the file. To pr...Rule Medium Severity -
Verify /boot/grub2/user.cfg User Ownership
The file <code>/boot/grub2/user.cfg</code> should be owned by the <code>root</code> user to prevent reading or modification of the file. To proper...Rule Medium Severity -
Verify /boot/grub2/grub.cfg Permissions
File permissions for <code>/boot/grub2/grub.cfg</code> should be set to 600. To properly set the permissions of <code>/boot/grub2/grub.cfg</code>,...Rule Medium Severity -
Verify /boot/grub2/user.cfg Permissions
File permissions for <code>/boot/grub2/user.cfg</code> should be set to 600. To properly set the permissions of <code>/boot/grub2/user.cfg</code>,...Rule Medium Severity -
Set Boot Loader Password in grub2
The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings. <br><br> Since plaintext passw...Rule High Severity -
UEFI GRUB2 bootloader configuration
UEFI GRUB2 bootloader configurationGroup -
Verify the UEFI Boot Loader grub.cfg Group Ownership
The file <code>/boot/grub2/grub.cfg</code> should be group-owned by the <code>root</code> group to prevent destruction or modification of the file....Rule Medium Severity -
Verify /boot/grub2/user.cfg Group Ownership
The file <code>/boot/grub2/user.cfg</code> should be group-owned by the <code>root</code> group to prevent reading or modification of the file. To...Rule Medium Severity -
Verify the UEFI Boot Loader grub.cfg User Ownership
The file <code>/boot/grub2/grub.cfg</code> should be owned by the <code>root</code> user to prevent destruction or modification of the file. To pr...Rule Medium Severity -
Verify /boot/grub2/user.cfg User Ownership
The file <code>/boot/grub2/user.cfg</code> should be owned by the <code>root</code> user to prevent reading or modification of the file. To proper...Rule Medium Severity -
Verify the UEFI Boot Loader grub.cfg Permissions
File permissions for <code>/boot/grub2/grub.cfg</code> should be set to 700. To properly set the permissions of <code>/boot/grub2/grub.cfg</code>,...Rule Medium Severity -
Verify /boot/grub2/user.cfg Permissions
File permissions for <code>/boot/grub2/user.cfg</code> should be set to 600. To properly set the permissions of <code>/boot/grub2/user.cfg</code>,...Rule Medium Severity -
Set the UEFI Boot Loader Admin Username to a Non-Default Value
The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings. <br><br> To maximize the prote...Rule Medium Severity -
Set the UEFI Boot Loader Password
The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings. <br><br> Since plaintext passw...Rule High Severity -
zIPL bootloader configuration
During the boot process, the bootloader is responsible for starting the execution of the kernel and passing options to it. The default Red Hat Ente...Group -
Enable Auditing to Start Prior to the Audit Daemon in zIPL
To ensure all processes can be audited, even those which start prior to the audit daemon, check that all boot entries in <code>/boot/loader/entries...Rule Medium Severity -
Protect Random-Number Entropy Pool
The I/O operations of the Linux kernel block layer due to their inherently unpredictable execution times have been traditionally considered as a re...Group -
Extend Audit Backlog Limit for the Audit Daemon in zIPL
To improve the kernel capacity to queue all log events, even those which start prior to the audit daemon, check that all boot entries in <code>/boo...Rule Medium Severity -
Ensure all zIPL boot entries are BLS compliant
Ensure that zIPL boot entries fully adheres to Boot Loader Specification (BLS) by checking that <code>/etc/zipl.conf</code> doesn't contain <code>i...Rule Medium Severity -
Ensure zIPL bootmap is up to date
Make sure that <code>/boot/bootmap</code> is up to date.<br> Every time a boot entry or zIPL configuration is changed <code>/boot/bootmap</code> ne...Rule Medium Severity -
Ensure SELinux Not Disabled in zIPL
To ensure SELinux is not disabled at boot time, check that no boot entry in <code>/boot/loader/entries/*.conf</code> has <code>selinux=0</code> inc...Rule Medium Severity -
Configure kernel to zero out memory before allocation in zIPL
To ensure that the kernel is configured to zero out memory before allocation, check that all boot entries in <code>/boot/loader/entries/*.conf</cod...Rule Medium Severity -
Enable randomization of the page allocator in zIPL
To enable the randomization of the page allocator in the kernel, check that all boot entries in <code>/boot/loader/entries/*.conf</code> have <code...Rule Medium Severity -
Enable page allocator poisoning in zIPL
To enable poisoning of free pages, check that all boot entries in <code>/boot/loader/entries/*.conf</code> have <code>page_poison=1</code> included...Rule Medium Severity -
Enable SLUB/SLAB allocator poisoning in zIPL
To enable poisoning of SLUB/SLAB objects, check that all boot entries in <code>/boot/loader/entries/*.conf</code> have <code>slub_debug=P</code> in...Rule Medium Severity -
Ensure debug-shell service is not enabled in zIPL
systemd's <code>debug-shell</code> service is intended to diagnose systemd related boot issues with various <code>systemctl</code> commands. Once e...Rule Medium Severity -
Ensure Solid State Drives Do Not Contribute To Random-Number Entropy Pool
For each solid-state drive on the system, run:# echo 0 > /sys/block/DRIVE/queue/add_random
Rule Medium Severity -
Kernel Configuration
Contains rules that check the kernel configuration that was used to build it.Group -
Hash function for kernel module signing
The hash function to use when signing modules during kernel build process.Value -
Key and certificate for kernel module signing
The private key and certificate to use when signing modules during kernel build process. On systems where the OpenSSL ENGINE_pkcs11 is functional —...Value -
Kernel panic timeout
The time, in seconds, to wait until a reboot occurs. If the value is <code>0</code> the system never reboots. If the value is less than <code>0</co...Value -
Do not allow ACPI methods to be inserted/replaced at run time
This debug facility allows ACPI AML methods to be inserted and/or replaced without rebooting the system. This configuration is available from kerne...Rule Low Severity -
Emulate Privileged Access Never (PAN)
Enabling this option prevents the kernel from accessing user-space memory directly by pointing TTBR0_EL1 to a reserved zeroed area and reserved ASI...Rule Medium Severity -
Disable kernel support for MISC binaries
Enabling <code>CONFIG_BINFMT_MISC</code> makes it possible to plug wrapper-driven binary formats into the kernel. This is specially useful for prog...Rule Medium Severity -
Enable support for BUG()
Disabling this option eliminates support for BUG and WARN, reducing the size of your kernel image and potentially quietly ignoring numerous fatal c...Rule Medium Severity -
Trigger a kernel BUG when data corruption is detected
This option makes the kernel BUG when it encounters data corruption in kernel memory structures when they get checked for validity. This configurat...Rule Low Severity -
Disable compatibility with brk()
Enabling compatiliby with <code>brk()</code> allows legacy binaries to run (i.e. those linked against libc5). But this compatibility comes at the c...Rule Medium Severity -
Disable the 32-bit vDSO
Certain buggy versions of glibc (2.3.3) will crash if they are presented with a 32-bit vDSO that is not mapped at the address indicated in its segm...Rule Low Severity -
Enable checks on credential management
Enable this to turn on some debug checking for credential management. The additional code keeps track of the number of pointers from task_structs t...Rule Low Severity -
Disable kernel debugfs
<code>debugfs</code> is a virtual file system that kernel developers use to put debugging files into. Enable this option to be able to read and wri...Rule Low Severity -
Enable checks on linked list manipulation
Enable this to turn on extended checks in the linked-list walking routines. The configuration that was used to build kernel is available at <code>...Rule Low Severity -
Enable checks on notifier call chains
Enable this to turn on sanity checking for notifier call chains. This is most useful for kernel developers to make sure that modules properly unreg...Rule Low Severity
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