Guide to the Secure Configuration of Red Hat Enterprise Linux 7
Rules, Groups, and Values defined within the XCCDF Benchmark
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Add nodev Option to /var/tmp
The <code>nodev</code> mount option can be used to prevent device files from being created in <code>/var/tmp</code>. Legitimate character and block...Rule Medium Severity -
Add noexec Option to /var/tmp
The <code>noexec</code> mount option can be used to prevent binaries from being executed out of <code>/var/tmp</code>. Add the <code>noexec</code> ...Rule Medium Severity -
Add nosuid Option to /var/tmp
The <code>nosuid</code> mount option can be used to prevent execution of setuid programs in <code>/var/tmp</code>. The SUID and SGID permissions sh...Rule Medium Severity -
Verify Permissions on Important Files and Directories Are Configured in /etc/permissions.local
Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses the ...Group -
Restrict Programs from Dangerous Execution Patterns
The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution ar...Group -
kernel.unprivileged_bpf_disabled
Prevent unprivileged processes from using the bpf() syscall.Value -
Disable the uvcvideo module
If the device contains a camera it should be covered or disabled when not in use.Rule Medium Severity -
Restrict Access to Kernel Message Buffer
To set the runtime status of the <code>kernel.dmesg_restrict</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.dmesg...Rule Low Severity -
Disable Kernel Image Loading
To set the runtime status of the <code>kernel.kexec_load_disabled</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel....Rule Medium Severity -
Disable loading and unloading of kernel modules
To set the runtime status of the <code>kernel.modules_disabled</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.mod...Rule Medium Severity -
Kernel panic on oops
To set the runtime status of the <code>kernel.panic_on_oops</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.panic_...Rule Medium Severity -
Limit CPU consumption of the Perf system
To set the runtime status of the <code>kernel.perf_cpu_time_max_percent</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w k...Rule Medium Severity -
Limit sampling frequency of the Perf system
To set the runtime status of the <code>kernel.perf_event_max_sample_rate</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w ...Rule Medium Severity -
Disallow kernel profiling by unprivileged users
To set the runtime status of the <code>kernel.perf_event_paranoid</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel....Rule Low Severity -
Configure maximum number of process identifiers
To set the runtime status of the <code>kernel.pid_max</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.pid_max=6553...Rule Medium Severity -
Disallow magic SysRq key
To set the runtime status of the <code>kernel.sysrq</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.sysrq=0</pre> ...Rule Medium Severity -
Restrict usage of ptrace to descendant processes
To set the runtime status of the <code>kernel.yama.ptrace_scope</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.ya...Rule Medium Severity -
Prevent applications from mapping low portion of virtual memory
To set the runtime status of the <code>vm.mmap_min_addr</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w vm.mmap_min_addr=...Rule Medium Severity -
Disable Core Dumps
A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases,...Group -
Disable core dump backtraces
The <code>ProcessSizeMax</code> option in <code>[Coredump]</code> section of <code>/etc/systemd/coredump.conf</code> specifies the maximum size in ...Rule Medium Severity -
Disable storing core dump
The <code>Storage</code> option in <code>[Coredump]</code> sectionof <code>/etc/systemd/coredump.conf</code> can be set to <code>none</code> to dis...Rule Medium Severity -
Ensure No Daemons are Unconfined by SELinux
Daemons for which the SELinux policy does not contain rules will inherit the context of the parent process. Because daemons are launched during sta...Rule Medium Severity -
Disable Core Dumps for SUID programs
To set the runtime status of the <code>fs.suid_dumpable</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w fs.suid_dumpable=...Rule Medium Severity -
Daemon Umask
The umask is a per-process setting which limits the default permissions for creation of new files and directories. The system includes initializati...Group -
daemon umask
Enter umask for daemonsValue -
Set Daemon Umask
The file <code>/etc/init.d/functions</code> includes initialization parameters for most or all daemons started at boot time. Many daemons on the sy...Rule Unknown Severity -
Enable ExecShield
ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These featu...Group -
kernel.kptr_restrict
Configure exposition of kernel pointer addressesValue -
Enable ExecShield via sysctl
By default on Red Hat Enterprise Linux 7 64-bit systems, ExecShield is enabled and can only be disabled if the hardware does not support ExecShield...Rule Medium Severity -
Restrict Exposed Kernel Pointer Addresses Access
To set the runtime status of the <code>kernel.kptr_restrict</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.kptr_r...Rule Medium Severity -
Enable Randomized Layout of Virtual Address Space
To set the runtime status of the <code>kernel.randomize_va_space</code> kernel parameter, run the following command: <pre>$ sudo sysctl -w kernel.r...Rule Medium Severity -
Enable Execute Disable (XD) or No Execute (NX) Support on x86 Systems
Recent processors in the x86 family support the ability to prevent code execution on a per memory page basis. Generically and on AMD processors, th...Group -
cron_userdomain_transition SELinux Boolean
default - Default SELinux boolean setting.
on - SELinux boolean is enabled.
off - SELinux boolean is disabled.Value -
cups_execmem SELinux Boolean
default - Default SELinux boolean setting.
on - SELinux boolean is enabled.
off - SELinux boolean is disabled.Value -
Enable NX or XD Support in the BIOS
Reboot the system and enter the BIOS or Setup configuration menu. Navigate the BIOS configuration menu and make sure that the option is enabled. Th...Rule Medium Severity -
Install PAE Kernel on Supported 32-bit x86 Systems
Systems that are using the 64-bit x86 kernel package do not need to install the kernel-PAE package because the 64-bit x86 kernel already includes t...Rule Unknown Severity -
Memory Poisoning
Memory Poisoning consists of writing a special value to uninitialized or freed memory. Poisoning can be used as a mechanism to prevent leak of info...Group -
slub_debug - debug options
Defines the debug options to use inslub_debugkernel command line argument.Value -
Enable page allocator poisoning
To enable poisoning of free pages, add the argument <code>page_poison=1</code> to the default GRUB 2 command line for the Linux operating system. T...Rule Medium Severity -
Enable SLUB/SLAB allocator poisoning
To enable poisoning of SLUB/SLAB objects, add the argument <code>slub_debug=<xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_slub_debug...Rule Medium Severity -
SELinux
SELinux is a feature of the Linux kernel which can be used to guard against misconfigured or compromised programs. SELinux enforces the idea that p...Group -
SELinux policy
Type of policy in use. Possible values are: <br>targeted - Only targeted network daemons are protected. <br>strict - Full SELinux protection. <br>m...Value -
SELinux state
enforcing - SELinux security policy is enforced. <br>permissive - SELinux prints warnings instead of enforcing. <br>disabled - SELinux is fully dis...Value -
Install libselinux Package
Thelibselinuxpackage can be installed with the following command:$ sudo yum install libselinux
Rule High Severity -
Install policycoreutils Package
Thepolicycoreutilspackage can be installed with the following command:$ sudo yum install policycoreutils
Rule Low Severity -
Uninstall mcstrans Package
The <code>mcstransd</code> daemon provides category label information to client processes requesting information. The label translations are define...Rule Low Severity -
Uninstall setroubleshoot-plugins Package
The SETroubleshoot plugins are used to analyze SELinux AVC data. The service provides information around configuration errors, unauthorized intrusi...Rule Low Severity -
Uninstall setroubleshoot-server Package
The SETroubleshoot service notifies desktop users of SELinux denials. The service provides information around configuration errors, unauthorized in...Rule Low Severity -
Uninstall setroubleshoot Package
The SETroubleshoot service notifies desktop users of SELinux denials. The service provides information around configuration errors, unauthorized in...Rule Low Severity -
Ensure SELinux Not Disabled in the kernel arguments
SELinux can be disabled at boot time by disabling it via a kernel argument. Remove any instances of <code>selinux=0</code> from the kernel argument...Rule Medium Severity
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