Guide to the Secure Configuration of OpenEmbedded
Rules, Groups, and Values defined within the XCCDF Benchmark
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Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session
To configure the number of retry prompts that are permitted per-session: Edit the <code>pam_pwquality.so</code> statement in <code>/etc/pam.d/system-auth</code> to show <code>retry=<xccdf-1.2:s...Rule Medium Severity -
Set Password Hashing Algorithm
The system's default algorithm for storing password hashes in/etc/shadowis SHA-512. This can be configured in several locations.Group -
Protect Physical Console Access
It is impossible to fully protect a system from an attacker with physical access, so securing the space in which the system is located should be considered a necessary step. However, there are some...Group -
Require Authentication for Emergency Systemd Target
Emergency mode is intended as a system recovery method, providing a single user root access to the system during a failed boot sequence. <br> <br> By default, Emergency mode is protected by...Rule Medium Severity -
Require Authentication for Single User Mode
Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup. <br> <br> By default, single-user mode is ...Rule Medium Severity -
number of days after a password expires until the account is permanently disabled
The number of days to wait after a password expires, until the account will be permanently disabled.Value -
Ensure All Accounts on the System Have Unique Names
Ensure accounts on the system have unique names. To ensure all accounts have unique names, run the following command: <pre>$ sudo getent passwd | awk -F: '{ print $1}' | uniq -d</pre> If a usernam...Rule Medium Severity -
Use Centralized and Automated Authentication
Implement an automated system for managing user accounts that minimizes the risk of errors, either intentional or deliberate. This system should integrate with an existing enterprise user managemen...Rule Medium Severity -
Set Password Expiration Parameters
The file <code>/etc/login.defs</code> controls several password-related settings. Programs such as <code>passwd</code>, <code>su</code>, and <code>login</code> consult <code>/etc/login.defs</code> ...Group -
maximum password age
Maximum age of password in daysValue -
minimum password age
Minimum age of password in daysValue -
minimum password length
Minimum number of characters in passwordValue -
warning days before password expires
The number of days' warning given before a password expires.Value -
Set Password Minimum Age
To specify password minimum age for new accounts, edit the file <code>/etc/login.defs</code> and add or correct the following line: <pre>PASS_MIN_DAYS <xccdf-1.2:sub idref="xccdf_org.ssgproject.con...Rule Medium Severity -
Set Password Minimum Length in login.defs
To specify password length requirements for new accounts, edit the file <code>/etc/login.defs</code> and add or correct the following line: <pre>PASS_MIN_LEN <xccdf-1.2:sub idref="xccdf_org.ssgproj...Rule Medium Severity -
Set Existing Passwords Maximum Age
Configure non-compliant accounts to enforce a <xccdf-1.2:sub idref="xccdf_org.ssgproject.content_value_var_accounts_maximum_age_login_defs" use="legacy"></xccdf-1.2:sub>-day maximum password lifeti...Rule Medium Severity -
Set Existing Passwords Minimum Age
Configure non-compliant accounts to enforce a 24 hours/1 day minimum password lifetime by running the following command:$ sudo chage -m 1 USERRule Medium Severity -
Set Password Warning Age
To specify how many days prior to password expiration that a warning will be issued to users, edit the file <code>/etc/login.defs</code> and add or correct the following line: <pre>PASS_WARN_AGE <...Rule Medium Severity -
Verify Proper Storage and Existence of Password Hashes
By default, password hashes for local accounts are stored in the second field (colon-separated) in <code>/etc/shadow</code>. This file should be readable only by processes running with root credent...Group -
Restrict Root Logins
Direct root logins should be allowed only for emergency use. In normal situations, the administrator should access the system via a unique unprivileged account, and then use <code>su</code> or <cod...Group -
Verify Only Root Has UID 0
If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed. <br> If the account is asso...Rule High Severity -
Verify Root Has A Primary GID 0
Therootuser should have a primary group of 0.Rule High Severity -
Ensure that System Accounts Do Not Run a Shell Upon Login
Some accounts are not associated with a human user of the system, and exist to perform some administrative functions. Should an attacker be able to log into these accounts, they should not be grant...Rule Medium Severity -
Restrict Serial Port Root Logins
To restrict root logins on serial ports, ensure lines of this form do not appear in/etc/securetty:ttyS0 ttyS1
Rule Medium Severity -
Restrict Virtual Console Root Logins
To restrict root logins through the (deprecated) virtual console devices, ensure lines of this form do not appear in/etc/securetty:vc/1 vc/2 vc/3 vc/4
Rule Medium Severity -
Enforce usage of pam_wheel for su authentication
To ensure that only users who are members of the <code>wheel</code> group can run commands with altered privileges through the <code>su</code> command, make sure that the following line exists in t...Rule Medium Severity -
Secure Session Configuration Files for Login Accounts
When a user logs into a Unix account, the system configures the user's session by reading a number of files. Many of these files are located in the user's home directory, and may have weak permissi...Group -
All Interactive User Home Directories Must Be Group-Owned By The Primary Group
Change the group owner of interactive users home directory to the group found in <code>/etc/passwd</code>. To change the group owner of interactive users home directory, use the following command: ...Rule Medium Severity -
All Interactive User Home Directories Must Be Owned By The Primary User
Change the owner of interactive users home directories to that correct owner. To change the owner of a interactive users home directory, use the following command: <pre>$ sudo chown <i>USER</i> /ho...Rule Medium Severity -
Ensure that User Home Directories are not Group-Writable or World-Readable
For each human user of the system, view the permissions of the user's home directory: <pre># ls -ld /home/<i>USER</i> </pre> Ensure that the directory is not group-writable and that it is n...Rule Medium Severity -
Ensure that No Dangerous Directories Exist in Root's Path
The active path of the root account can be obtained by starting a new root shell and running: <pre># echo $PATH</pre> This will produce a colon-separated list of directories in the path. <br> ...Group -
Ensure that Root's Path Does Not Include World or Group-Writable Directories
For each element in root's path, run:# ls -ld DIRand ensure that write permissions are disabled for group and other.Rule Medium Severity -
Ensure that Root's Path Does Not Include Relative Paths or Null Directories
Ensure that none of the directories in root's path is equal to a single <code>.</code> character, or that it contains any instances that lead to relative path traversal, such as <code>..</code> or ...Rule Unknown Severity -
Sensible umask
Enter default user umaskValue -
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_hash" use="legacy"></xccdf-1.2:sub> as the hash func...Rule Medium Severity -
System Audit Logs Must Have Mode 0750 or Less Permissive
If <code>log_group</code> in <code>/etc/audit/auditd.conf</code> is set to a group other than the <code>root</code> group account, change the mode of the audit log files with the following command...Rule Medium Severity -
Disable vsftpd if Possible
To minimize attack surface, disable vsftpd if at all possible.Group -
Records Events that Modify Date and Time Information
Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All c...Group -
Configure vsftpd to Provide FTP Service if Necessary
The primary vsftpd configuration file is/etc/vsftpd.conf, if that file exists, or/etc/vsftpd/vsftpd.confif it does not.Group -
Force kernel panic on uncorrected MCEs
A Machine Check Exception is an error generated by the CPU itdetects an error in itself, memory or I/O devices. These errors may be corrected and generate a check log entry, if an error cannot be c...Rule Medium Severity -
Ensure SMAP is not disabled during boot
The SMAP is used to prevent the supervisor mode from unintentionally reading/writing into memory pages in the user space, it is enabled by default since Linux kernel 3.7. But it could be disabled t...Rule Medium Severity -
Ensure SMEP is not disabled during boot
The SMEP is used to prevent the supervisor mode from executing user space code, it is enabled by default since Linux kernel 3.0. But it could be disabled through kernel boot parameters. Ensure tha...Rule Medium Severity -
Disable merging of slabs with similar size
The kernel may merge similar slabs together to reduce overhead and increase cache hotness of objects. Disabling merging of slabs keeps the slabs separate and reduces the risk of kernel heap overflo...Rule Medium 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 into executing code from a future indirect branch cho...Rule High 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. To properly set the group owner of <code>/boot/g...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 properly set the owner of <code>/boot/grub2/grub.cfg...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>, run the command: <pre>$ sudo chmod 600 /boot/grub...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 passwords are a security risk, generate a hash...Rule High 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 reliable source to contribute to random-number entro...Group
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