CompTIA CompTIA Certifications XK0-005 Questions & Answers

• Question 11:

  An administrator installed an application from source into /opt/operations1/ and has received numerous reports that users are not able to access the application without having to use the full path /opt/operations1/bin/*. Which of the following commands should be used to resolve this issue?

  A. echo 'export PATH=$PATH:/opt/operations1/bin' >> /etc/profile

  B. echo 'export PATH=/opt/operations1/bin' >> /etc/profile

  C. echo 'export PATH=$PATH/opt/operations1/bin' >> /etc/profile

  D. echo 'export $PATH:/opt/operations1/bin' >> /etc/profile

  Correct Answer: A

  Explanation: The command echo 'export PATH=$PATH:/opt/operations1/bin' >> /etc/profile should be used to resolve the issue of users not being able to access the application without using the full path. The echo command prints the given string to the standard output. The export command sets an environment variable and makes it available to all child processes. The PATH variable contains a list of directories where the shell looks for executable files. The $PATH expands to the current value of the PATH variable. The : separates the directories in the list. The /opt/operations1/bin is the directory where the application is installed. The >> operator appends the output to the end of the file. The /etc/profile file is a configuration file that is executed when a user logs in. The command echo 'export PATH=$PATH:/opt/operations1/bin' >> /etc/profile will add the /opt/operations1/bin directory to the PATH variable for all users and allow them to access the application without using the full path. This is the correct command to use to resolve the issue. The other options are incorrect because they either overwrite the PATH variable (echo 'export PATH=/opt/operations1/bin' >> /etc/profile) or do not use the correct syntax (echo 'export PATH=$PATH/opt/operations1/bin' >> /etc/profile or echo 'export $PATH:/opt/operations1/bin' >> /etc/profile). References: CompTIA Linux+ (XK0- 005) Certification Study Guide, Chapter 9: Working with the Linux Shell, page 295.

• Question 12:

  A junior administrator is setting up a new Linux server that is intended to be used as a router at a remote site. Which of the following parameters will accomplish this goal?

  

  A. Option A

  B. Option B

  C. Option C

  D. Option D

  Correct Answer: C

  Explanation: The parameter net.ipv4.ip_forward=1 will accomplish the goal of setting up a new Linux server as a router. This parameter enables the IP forwarding feature, which allows the server to forward packets between different network interfaces. This is necessary for a router to route traffic between different networks. The parameter can be set in the /etc/sysctl.conf file or by using the sysctl command. This is the correct parameter to use to accomplish the goal. The other options are incorrect because they either do not exist (net.ipv4.ip_forwarding or net.ipv4.ip_route) or do not enable IP forwarding (net.ipv4.ip_forward=0). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 12: Managing Network Connections, page 382.

• Question 13:

  Which of the following actions are considered good security practices when hardening a Linux server? (Select two).

  A. Renaming the root account to something else

  B. Removing unnecessary packages

  C. Changing the default shell to /bin/csh

  D. Disabling public key authentication

  E. Disabling the SSH root login possibility

  F. Changing the permissions on the root filesystem to 600

  Correct Answer: BE

  Some good security practices when hardening a Linux server are:

  Removing unnecessary packages (B) to reduce the attack surface and eliminate potential vulnerabilities

  Disabling the SSH root login possibility (E) to prevent unauthorized access and brute-force attacks on the root account References:

  [CompTIA Linux+ Study Guide], Chapter 9: Securing Linux, Section: Hardening Linux

  [How to Harden Your Linux Server]

• Question 14:

  A systems administrator is tasked with preventing logins from accounts other than root, while the file /etc/nologin exists. Which of the following PAM modules will accomplish this task?

  A. pam_login.so

  B. pam_access.so

  C. pam_logindef.so

  D. pam_nologin.so

  Correct Answer: D

  Explanation: The PAM module pam_nologin.so will prevent logins from accounts other than root, while the file /etc/nologin exists. This module checks for the existence of the file /etc/nologin and displays its contents to the user before denying access. The root user is exempt from this check and can still log in. This is the correct module to accomplish the task. The other options are incorrect because they are either non-existent modules (pam_login.so or pam_logindef.so) or do not perform the required function (pam_access.so controls access based on host, user, or time). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 15: Managing Users and Groups, page 471.

• Question 15:

  A Linux administrator wants to set the SUID of a file named dev_team.text with 744 access rights. Which of the following commands will achieve this goal?

  A. chmod 4744 dev_team.txt

  B. chmod 744 --setuid dev_team.txt

  C. chmod -c 744 dev_team.txt

  D. chmod -v 4744 --suid dev_team.txt

  Correct Answer: A

  Explanation: The command that will set the SUID of a file named dev_team.txt with 744 access rights is chmod 4744 dev_team.txt. This command will use the chmod utility to change the file mode bits of dev_team.txt. The first digit (4) represents the SUID bit, which means that when someone executes dev_team.txt, it will run with the permissions of the file owner. The next three digits (744) represent the read, write, and execute permissions for the owner (7), group (4), and others (4). This means that the owner can read, write, and execute dev_team.txt, while the group and others can only read it. The other options are not correct commands for setting the SUID of a file with 744 access rights. The chmod 744 -setuid dev_team.txt command is invalid because there is no -- setuid option in chmod. The chmod -c 744 dev_team.txt command will change the file mode bits to 744, but it will not set the SUID bit. The -c option only means that chmod will report when a change is made. The chmod -v 4744 --suid dev_team.txt command is also invalid because there is no --suid option in chmod. The -v option only means that chmod will output a diagnostic for every file processed. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 8: Managing Users and Groups; chmod(1) - Linux manual page

• Question 16:

  A newly created container has been unable to start properly, and a Linux administrator is analyzing the cause of the failure. Which of the following will allow the administrator to determine the FIRST command that is executed inside the container right after it starts?

  A. docker export

  B. docker info

  C. docker start

  D. docker inspect

  Correct Answer: D

  Explanation: The command that will allow the administrator to determine the first command that is executed inside the container right after it starts is docker inspect . This command will display detailed information about the container, including its configuration, state, network settings, mounts, and logs. One of the configuration fields is "Entrypoint", which shows the command that is executed when the container is run. The entrypoint can be specified in the Dockerfile or overridden at runtime using the --entrypoint option. The other options are not correct commands for determining the first command that is executed inside the container. The docker export command will export the contents of the container's filesystem as a tar archive to STDOUT. This will not show the entrypoint of the container, but only its files. The docker info command is invalid because docker info does not take any arguments. It shows system-wide information about Docker, such as the number of containers, images, volumes, networks, and storage drivers. The docker start command will start a stopped container and attach its STDOUT and STDERR to the terminal. This will not show the entrypoint of the container, but only its output. References: docker inspect | Docker Docs; docker export | Docker Docs; docker info | Docker Docs; docker start | Docker Docs

• Question 17:

  A systems administrator is enabling LUKS on a USB storage device with an ext4 filesystem format. The administrator runs dmesg and notices the following output:

  

  Given this scenario, which of the following should the administrator perform to meet these requirements? (Select three).

  A. gpg /dev/sdcl

  B. pvcreate /dev/sdc

  C. mkfs . ext4 /dev/mapper/LUKSCJ001 - L ENCRYPTED

  D. umount / dev/ sdc

  E. fdisk /dev/sdc

  F. mkfs . vfat /dev/mapper/LUKS0001 -- L ENCRYPTED

  G. wipefs --a/dev/sdbl

  H. cryptsetup IuksFormat /dev/ sdcl

  Correct Answer: CDH

  To enable LUKS on a USB storage device with an ext4 filesystem format, the administrator needs to perform the following steps:

  Unmount the device if it is mounted using umount /dev/sdc (D) Create a partition table on the device using fdisk /dev/sdc (E) Format the partition with LUKS encryption using cryptsetup luksFormat /dev/sdc1 (H)

  Open the encrypted partition using cryptsetup luksOpen /dev/sdc1 LUKS0001 Create an ext4 filesystem on the encrypted partition using mkfs.ext4 /dev/mapper/LUKS0001 ?

  Mount the encrypted partition using mount /dev/mapper/LUKS0001 /mnt References:

  [CompTIA Linux+ Study Guide], Chapter 9: Securing Linux, Section: Encrypting Disks

  [How to Encrypt USB Drive on Ubuntu 18.04]

• Question 18:

  A Linux administrator copied a Git repository locally, created a feature branch, and committed some changes to the feature branch. Which of the following Git actions should the Linux administrator use to publish the changes to the main branch of the remote repository?

  A. rebase

  B. tag

  C. commit

  D. push

  Correct Answer: D

  Explanation: The push action is used to publish the changes made in a local branch to a remote branch of a Git repository. This action will update the remote branch with the commits made in the local branch and synchronize the two branches. The rebase action is used to reapply commits from one branch onto another branch, creating a linear history of commits. This action does not publish any changes to a remote repository. The tag action is used to create an annotated reference to a specific commit in a Git repository. This action does not publish any changes to a remote repository. The commit action is used to record changes made in the local repository and create a new snapshot of the project state. This action does not publish any changes to a remote repository. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 20: Writing and Executing Bash Shell Scripts, page 579.

• Question 19:

  Which of the following tools is commonly used for creating CI/CD pipelines?

  A. Chef

  B. Puppet

  C. Jenkins

  D. Ansible

  Correct Answer: C

  Explanation: The tool that is commonly used for creating CI/CD pipelines is Jenkins. Jenkins is an open-source automation server that enables continuous integration and continuous delivery (CI/CD) of software projects. Jenkins allows developers to build, test, and deploy code changes automatically and frequently using various plugins and integrations. Jenkins also supports distributed builds, parallel execution, pipelines as code, and real-time feedback. References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 19: Managing Source Code; Jenkins

• Question 20:

  Users in the human resources department are trying to access files in a newly created directory. Which of the following commands will allow the users access to the files?

  A. chattr

  B. chgrp

  C. chage

  D. chcon

  Correct Answer: B

  The chgrp command is used to change the group ownership of files and directories. By using this command, the administrator can assign the files in the newly created directory to the human resources group, which will allow the users in that

  group to access them. The other commands are not relevant for this task. For example:

  chattr is used to change the file attributes, such as making them immutable or append-only1.

  chage is used to change the password expiration information for a user account2. chcon is used to change the security context of files and directories, which is related to SELinux3.

  References:

  The CompTIA Linux+ Certification Exam Objectives mention that the candidate should be able to "manage file and directory ownership and permissions" as part of the Hardware and System Configuration domain4.

  The web search result 2 explains how to use the chgrp command with examples. The web search result 3 compares the chmod and chgrp commands and their effects on file permissions.