Guide to the Secure Configuration of Red Hat Enterprise Linux 9
Rules, Groups, and Values defined within the XCCDF Benchmark
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Disallow merge of slab caches
For reduced kernel memory fragmentation, slab caches can be merged when they share the same size and other characteristics. This carries a risk of ...Rule Medium Severity -
Enable SLUB debugging support
SLUB has extensive debug support features and this allows the allocator validation checking to be enabled. The configuration that was used to buil...Rule Medium Severity -
Stack Protector buffer overlow detection
This feature puts, at the beginning of functions, a canary value on the stack just before the return address, and validates the value just before a...Rule Medium Severity -
Strong Stack Protector
This features adds canary logic protection to more kinds of vulnerable functions than CONFIG_STACKPROTECTOR, but not to all functions so that perfo...Rule Medium Severity -
Make the kernel text and rodata read-only
When set, kernel text and rodata memory will be made read-only, and non-text memory will be made non-executable. This configuration is available fr...Rule Medium Severity -
Make the module text and rodata read-only
When set, module text and rodata memory will be made read-only, and non-text memory will be made non-executable. This configuration is available fr...Rule Medium Severity -
Configure rsyslogd to Accept Remote Messages If Acting as a Log Server
By default, <code>rsyslog</code> does not listen over the network for log messages. If needed, modules can be enabled to allow the rsyslog daemon t...Group -
Enable TCP/IP syncookie support
Normal TCP/IP networking is open to an attack known as SYN flooding. It is denial-of-service attack that prevents legitimate remote users from bein...Rule Medium Severity -
Unmap kernel when running in userspace (aka KAISER)
Speculation attacks against some high-performance processors can be used to bypass MMU permission checks and leak kernel data to userspace. This ca...Rule Medium Severity -
User a virtually-mapped stack
Enable this to use virtually-mapped kernel stacks with guard pages. This configuration is available from kernel 4.9. The configuration that was us...Rule Medium Severity -
Disable x86 vsyscall emulation
Disabling it is roughly equivalent to booting with vsyscall=none, except that it will also disable the helpful warning if a program tries to use a ...Rule Low Severity -
Kernel GCC plugin configuration
Contains rules that check the configuration of GCC plugins used by the compilerGroup -
Generate some entropy during boot and runtime
Instrument some kernel code to extract some entropy from both original and artificially created program state. This will help especially embedded s...Rule Medium Severity -
Randomize layout of sensitive kernel structures
Randomize at compile-time the layouts of structures that are entirely function pointers (and have not been manually annotated with __no_randomize_l...Rule Medium Severity -
Poison kernel stack before returning from syscalls
This option makes the kernel erase the kernel stack before returning from system calls. This has the effect of leaving the stack initialized to the...Rule Medium Severity -
Ensure syslog-ng is Installed
syslog-ng can be installed in replacement of rsyslog. The <code>syslog-ng-core</code> package can be installed with the following command: <pre> $ ...Rule Medium Severity -
Force initialization of variables containing userspace addresses
While the kernel is built with warnings enabled for any missed stack variable initializations, this warning is silenced for anything passed by refe...Rule Medium Severity -
zero-init everything passed by reference
Zero-initialize any stack variables that may be passed by reference and had not already been explicitly initialized. This configuration is availabl...Rule Medium Severity -
Configure Syslog
The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lac...Group -
Ensure rsyslog-gnutls is installed
TLS protocol support for rsyslog is installed. The <code>rsyslog-gnutls</code> package can be installed with the following command: <pre> $ sudo d...Rule Medium Severity
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