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Guide to the Secure Configuration of Red Hat Enterprise Linux 7

Rules, Groups, and Values defined within the XCCDF Benchmark

  • 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
  • Enable checks on scatter-gather (SG) table operations

    Scatter-gather tables are mechanism used for high performance I/O on DMA devices. Enable this to turn on checks on scatter-gather tables. The conf...
    Rule Low Severity
  • Configure low address space to protect from user allocation

    This is the portion of low virtual memory which should be protected from userspace allocation. This configuration is available from kernel 3.14, bu...
    Rule Medium Severity
  • Disable /dev/kmem virtual device support

    Disable support for the /dev/kmem device. The configuration that was used to build kernel is available at <code>/boot/config-*</code>. To chec...
    Rule Low Severity
  • Harden memory copies between kernel and userspace

    This option checks for obviously wrong memory regions when copying memory to/from the kernel (via copy_to_user() and copy_from_user() functions) by...
    Rule High Severity
  • Disable hibernation

    Enable the suspend to disk (STD) functionality, which is usually called "hibernation" in user interfaces. STD checkpoints the system and powers it ...
    Rule Medium Severity
  • Disable IA32 emulation

    Disables support for legacy 32-bit programs under a 64-bit kernel. The configuration that was used to build kernel is available at <code>/boot/con...
    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
  • Disable the IPv6 protocol

    Disable support for IP version 6 (IPv6). The configuration that was used to build kernel is available at <code>/boot/config-*</code>. To check...
    Rule Medium Severity
  • Disable kexec system call

    <code>kexec</code> is a system call that implements the ability to shutdown your current kernel, and to start another kernel. It is like a reboot b...
    Rule Low Severity
  • Disable legacy (BSD) PTY support

    Disable the Linux traditional BSD-like terminal names /dev/ptyxx for masters and /dev/ttyxx for slaves of pseudo terminals, and use only the modern...
    Rule Medium Severity
  • Enable module signature verification

    Check modules for valid signatures upon load. Note that this option adds the OpenSSL development packages as a kernel build dependency so that the ...
    Rule Medium Severity
  • Enable automatic signing of all modules

    Sign all modules during make modules_install. Without this option, modules must be signed manually, using the scripts/sign-file tool. The configur...
    Rule Medium Severity
  • Require modules to be validly signed

    Reject unsigned modules or signed modules with an unknown key. The configuration that was used to build kernel is available at <code>/boot/config-...
    Rule Medium Severity
  • Specify the hash to use when signing modules

    This configures the kernel to build and sign modules using <xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_kernel_config_module_sig_ha...
    Rule Medium Severity
  • Specify module signing key to use

    Setting this option to something other than its default of <code>certs/signing_key.pem</code> will disable the autogeneration of signing keys and a...
    Rule Medium Severity
  • Sign kernel modules with SHA-512

    This configures the kernel to build and sign modules using SHA512 as the hash function. The configuration that was used to build kernel is availab...
    Rule Medium Severity
  • net.ipv4.conf.default.shared_media

    Controls whether the system can send(router) or accept(host) RFC1620 shared media redirects. <code>shared_media</code> for the interface will be en...
    Value
  • Enable poison without sanity check

    Skip the sanity checking on alloc, only fill the pages with poison on free. This reduces some of the overhead of the poisoning feature. This config...
    Rule Medium Severity
  • Use zero for poisoning instead of debugging value

    Instead of using the existing poison value, fill the pages with zeros. This makes it harder to detect when errors are occurring due to sanitization...
    Rule Medium Severity
  • Remove the kernel mapping in user mode

    This feature reduces the number of hardware side channels by ensuring that the majority of kernel addresses are not mapped into userspace. This con...
    Rule High Severity
  • Kernel panic oops

    Enable the kernel to panic when it oopses. This has the same effect as setting oops=panic on the kernel command line. The configuration that was u...
    Rule Medium Severity
  • Kernel panic timeout

    Set the timeout value (in seconds) until a reboot occurs when the kernel panics. A timeout of 0 configures the system to wait forever. With a timeo...
    Rule Medium Severity
  • Disable support for /proc/kkcore

    Provides a virtual ELF core file of the live kernel. The configuration that was used to build kernel is available at <code>/boot/config-*</code>. ...
    Rule Low Severity
  • Randomize the address of the kernel image (KASLR)

    In support of Kernel Address Space Layout Randomization (KASLR), this randomizes the physical address at which the kernel image is decompressed and...
    Rule Medium Severity
  • Randomize the kernel memory sections

    Randomizes the base virtual address of kernel memory sections (physical memory mapping, vmalloc &amp; vmemmap). This configuration is available fro...
    Rule Medium Severity
  • Perform full reference count validation

    Enabling this switches the refcounting infrastructure from a fast unchecked atomic_t implementation to a fully state checked implementation, which ...
    Rule Medium Severity
  • Avoid speculative indirect branches in kernel

    Compile kernel with the retpoline compiler options to guard against kernel-to-user data leaks by avoiding speculative indirect branches. Requires a...
    Rule Medium Severity
  • Enable seccomp to safely compute untrusted bytecode

    This kernel feature is useful for number crunching applications that may need to compute untrusted bytecode during their execution. By using pipes ...
    Rule Medium Severity
  • Enable use of Berkeley Packet Filter with seccomp

    Enable tasks to build secure computing environments defined in terms of Berkeley Packet Filter programs which implement task-defined system call fi...
    Rule Medium Severity
  • Enable different security models

    This allows you to choose different security modules to be configured into your kernel. The configuration that was used to build kernel is availab...
    Rule Medium Severity
  • Disable mutable hooks

    Ensure kernel structures associated with LSMs are always mapped as read-only after system boot. The configuration that was used to build kernel is...
    Rule Medium Severity
  • Enable Yama support

    This enables support for LSM module Yama, which extends DAC support with additional system-wide security settings beyond regular Linux discretionar...
    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
  • 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
  • net.ipv4.icmp_echo_ignore_broadcasts

    Ignore all ICMP ECHO and TIMESTAMP requests sent to it via broadcast/multicast
    Value
  • 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
  • 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 compiler
    Group
  • 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 y...
    Rule Medium Severity
  • Ensure rsyslog is Installed

    Rsyslog is installed by default. The rsyslog package can be installed with the following command:
     $ sudo yum install rsyslog
    Rule Medium Severity
  • Enable rsyslog Service

    The <code>rsyslog</code> service provides syslog-style logging by default on Red Hat Enterprise Linux 7. The <code>rsyslog</code> service can be e...
    Rule Medium Severity
  • Disable Logwatch on Clients if a Logserver Exists

    Does your site have a central logserver which has been configured to report on logs received from all systems? If so: <pre>$ sudo rm /etc/cron.dail...
    Rule Unknown Severity
  • Ensure rsyslog Default File Permissions Configured

    rsyslog will create logfiles that do not already exist on the system. This settings controls what permissions will be applied to these newly create...
    Rule Medium Severity
  • Configure Logwatch on the Central Log Server

    Is this system the central log server? If so, edit the file /etc/logwatch/conf/logwatch.conf as shown below.
    Group
  • Configure Logwatch HostLimit Line

    On a central logserver, you want Logwatch to summarize all syslog entries, including those which did not originate on the logserver itself. The <co...
    Rule Unknown Severity
  • Configure Logwatch SplitHosts Line

    If <code>SplitHosts</code> is set, Logwatch will separate entries by hostname. This makes the report longer but significantly more usable. If it is...
    Rule Unknown Severity

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