CompTIA XK0-005 Online Practice Questions and Exam Preparation

CompTIA XK0-005 Online Questions & Answers

• Question 331:

  A hardened physical Linux system allows regular, unprivileged users to remotely connect to the server using SSH only. No sudo tool has been installed. Which of the following should the Linux administrator use to perform administrative tasks on this host? (Select two).

  A. Create an SSH key and copy it to the remote server to allow passwordless login
  B. Access the server's physical console and use the root user's password to log in
  C. Install the telnet server on this system to be able to use a root account
  D. Use the su command and enter the root user's password
  E. Install the sudo command using the unprivileged user's account
  F. Add the user to the wheel group
  B. Access the server's physical console and use the root user's password to log in
  D. Use the su command and enter the root user's password

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  Explanation

  Without sudo, the administrator must either access the system physically or use the su command to switch to the root account using the root password. Since the system is hardened and SSH is allowed, installing sudo or using Telnet would not be secure or permitted options. Physical access to the console or using su is the correct approach.

• Question 332:

  A Linux engineer needs to download a ZIP file and wants to set the nice of value to -10 for this new process. Which of the following commands will help to accomplish the task?

  A. $ nice -v -10 wget https://foo.com/installation.zip
  B. $ renice -v -10 wget https://foo.com/installation.2ip
  C. $ renice -10 wget https://foo.com/installation.zip
  D. $ nice -10 wget https://foo.com/installation.zip
  D. $ nice -10 wget https://foo.com/installation.zip

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  Explanation

  The nice -10 wget https://foo.com/installation.zip command will help to accomplish the task of downloading a ZIP file and setting the nice value to -10 for this new process. The nice command can be used to run a program with a modified

  scheduling priority, which affects how much CPU time the process receives. The nice value ranges from -20 (highest priority) to 19 (lowest priority), and the default value is 0. The -10 option specifies the nice value to be used for the wget

  command, which will download the ZIP file from the given URL. The nice -v -10 wget https://foo.com/installation.zip command is incorrect, as -v is not a valid option for nice. The renice -v -10 wget https://foo.com/installation.zip command is

  incorrect, as renice is used to change the priority of an existing process, not a new one. The renice -10 wget https://foo.com/installation.zip command is incorrect for the same reason as above.

  References: CompTIA Linux+ (XK0-005)

  Certification Study Guide, Chapter 15:

  Managing Memory and Process Execution, page 469.

• Question 333:

  Which of the following paths stores the configuration files in a Linux filesystem?

  A. /proc
  B. /home
  C. /root
  D. /etc
  D. /etc

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  Explanation

  The /etc directory contains configuration files for system-wide settings and services in Linux. Files like /etc/fstab, /etc/hosts, and /etc/passwd reside here, controlling various aspects of system behavior and service configurations.

• Question 334:

  Some servers in an organization have been compromised. Users are unable to access to the organization's web page and other services. While reviewing the system log, a systems administrator notices messages from the kernel regarding firewall rules:

  

  Which of the following commands will remediate and help resolve the issue?

  

  A. Option A
  B. Option B
  C. Option C
  D. Option D
  A. Option A

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  Explanation

  The command iptables -F will remediate and help resolve the issue. The issue is caused by the firewall rules that block the access to the organization's web page and other services. The output of dmesg | grep firewall shows that the kernel has dropped packets from the source IP address 192.168.1.100 to the destination port 80, which is the default port for HTTP. The command iptables -F will flush all the firewall rules and allow the traffic to pass through. This command will resolve the issue and restore the access to the web page and other services. The other options are incorrect because they either do not affect the firewall rules (ip route flush or ip addr flush) or do not exist (iptables - R).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 18: Securing Linux Systems, page 543.

• Question 335:

  Which of the following can reduce the attack surface area in relation to Linux hardening?

  A. Customizing the log-in banner
  B. Reducing the number of directories created
  C. Extending the SSH startup timeout period
  D. Enforcing password strength and complexity
  D. Enforcing password strength and complexity

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  Explanation

• Question 336:

  A Linux administrator is troubleshooting a memory-related issue. Based on the output of the commands:

  

  Which of the following commands would address the issue?

  A. top -p 8321
  B. kill -9 8321
  C. renice -10 8321
  D. free 8321
  B. kill -9 8321

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  Explanation

  The command that would address the memory-related issue is kill -9 8321. This command will send a SIGKILL signal to the process with the PID 8321, which is the mysqld process that is using 99.7% of the available memory according to the top output. The SIGKILL signal will terminate the process immediately and free up the memory it was using. However, this command should be used with caution as it may cause data loss or corruption if the process was performing some critical operations. The other options are not correct commands for addressing the memory-related issue. The top -p 8321 command will only display information about the process with the PID 8321, but will not kill it or reduce its memory usage. The renice -10 8321 command will change the priority (niceness) of the process with the PID 8321 to -10, which means it will have a higher scheduling priority, but this will not affect its memory consumption. The free 8321 command is invalid because free does not take a PID as an argument; free only displays information about the total, used, and free memory in the system.

  References: How to troubleshoot Linux server memory issues; kill(1) - Linux manual page

• Question 337:

  SIMULATION

  Junior system administrator had trouble installing and running an Apache web server on a Linux server. You have been tasked with installing the Apache web server on the Linux server and resolving the issue that prevented the junior

  administrator from running Apache.

  INSTRUCTIONS

  Install Apache and start the service. Verify that the Apache service is running with the defaults.

  Typing "help" in the terminal will show a list of relevant event commands.

  If at any time you would like to bring back the initial state of the simulation, please click the Reset All button.

  

  A. See the explanation below.
  B. PlaceHolder
  C. PlaceHolder
  D. PlaceHolder
  A. See the explanation below.

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  Explanation

  yum install httpd

  systemctl --now enable httpd

  systemctl status httpd

  netstat -tunlp | grep 80

  pkill

  systemctl restart httpd

  systemctl status httpd

• Question 338:

  A cloud engineer needs to block the IP address 192.168.10.50 from accessing a Linux server. Which of the following commands will achieve this goal?

  A. iptables -F INPUT -j 192.168.10.50 -m DROP
  B. iptables -A INPUT -s 192.168.10.30 -j DROP
  C. iptables -i INPUT --ipv4 192.168.10.50 -z DROP
  D. iptables -j INPUT 192.168.10.50 -p DROP
  B. iptables -A INPUT -s 192.168.10.30 -j DROP

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  Explanation

  The correct command to block the IP address 192.168.10.50 from accessing a Linux server is iptables -A INPUT -s 192.168.10.50 -j DROP. This command appends a rule to the INPUT chain that matches the source address 192.168.10.50

  and jumps to the DROP target, which discards the packet. The other commands are incorrect because they either have invalid syntax, wrong parameters, or wrong order of arguments.

  References:

  CompTIA Linux+ Study Guide, Fourth Edition, page 457-458.

• Question 339:

  A Linux administrator reviews a set of log output files and needs to identify files that contain any occurrence of the word denied. All log files containing entries in uppercase or lowercase letters should be included in the list. Which of the following commands should the administrator use to accomplish this task?

  A. find . -type f -print | xrags grep -ln denied
  B. find . -type f -print | xrags grep -nv denied
  C. find . -type f -print | xrags grep -wL denied
  D. find . -type f -print | xrags grep -li denied
  D. find . -type f -print | xrags grep -li denied

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  Explanation

  The command find . -type f -print | xargs grep -li denied will accomplish the task of identifying files that contain any occurrence of the word denied. The find command is a tool for searching for files and directories on Linux systems. The . is the starting point of the search, which means the current directory. The -type f option specifies the type of the file, which means regular file. The -print option prints the full file name on the standard output. The | is a pipe symbol that redirects the output of one command to the input of another command. The xargs command is a tool for building and executing commands from standard input. The grep command is a tool for searching for patterns in files or input. The -li option specifies the flags that the grep command should apply. The -l flag shows only the file names that match the pattern, instead of the matching lines. The -i flag ignores the case of the pattern, which means it matches both uppercase and lowercase letters. The denied is the pattern that the grep command should search for. The command find . - type f -print | xargs grep -li denied will find all the regular files in the current directory and its subdirectories, and then search for any occurrence of the word denied in those files, ignoring the case, and print only the file names that match the pattern. This will allow the administrator to identify files that contain any occurrence of the word denied. This is the correct command to use to accomplish the task. The other options are incorrect because they either do not ignore the case of the pattern (find . -type f -print | xargs grep -ln denied or find . -type f -print | xargs grep -wL denied) or do not show the file names that match the pattern (find . -type f -print | xargs grep -nv denied).

  References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 16: Managing Logging and Monitoring, page 489.

• Question 340:

  A new user is experiencing issues creating files in the folder /home/testuser/testdir/. The directory needs to be accessible for reading by other users in the system. The administrator gathers the following information:

  drwxr-xr-x. 2 root testuser 6 Oct 19 11:22 testdir

  Which of the following commands should the administrator use to solve the issue? (Select TWO.)

  A. chmod u+w /home/testuser/testdir/
  B. usermod -G root testuser
  C. chmod g+w /home/testuser/testdir/
  D. usermod -G testuser root
  E. chown newuser /home/testuser
  A. chmod u+w /home/testuser/testdir/
  C. chmod g+w /home/testuser/testdir/

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  Explanation