Review Questions
1. What does LKM stand for?
A. Linux Kernel Module
B. Linux Kernel Mode
C. Linked Kernel Module
D. Last Kernel Mode
2. What GCC command is used to compile a C++ file called source into an executable file
called game?
A. g++ source.c –o game
B. gcc source.c –o game
C. gcc make source.cpp –o game
D. g++ source.cpp –o game
3. What is the command to deny all users access from the network?
A. Cat “All:All”>> /etc/hosts.deny
B. Set “All:All”>> /etc/hosts.deny
C. IP deny “All:All”
D. Cat All:All deny
4. Of the following, which are common commercial Linux distributions?
A. SUSE, Knark, and Red Hat
B. SUSE, Adore, Debian, and Mandrake
C. SUSE, Debian, and Red Hat
D. SUSE, Adore, and Red Hat
5. What is a Linux live CD?
A. A Linux operating system that runs from a CD
B. A Linux operating system installed from a CD onto a hard drive
C. A Linux tool that runs applications from a CD
D. A Linux application that makes CDs
6. What type of attack can be disguised as an LKM?
A. DoS
B. Trojan
C. Spam virus
D. Rootkit
7. Which of the following is a reason to use Linux?
A. Linux has no security holes.
B. Linux is always up-to-date on security patches.
C. No rootkits can infect a Linux system.
D. Linux is flexible and can be modified.
8. Which of the following is not a way to harden Linux?
A. Physically secure the system.
B. Maintain a current patch level.
C. Change the default passwords.
D. Install all available services.
9. What type of file is used to create a Linux live CD?
A. ISO
B. CD
C. LIN
D. CDFS
10. Why is it important to use a known good distribution of Linux?
A. Source files can become corrupted if not downloaded properly.
B. Only certain distributions can be patched.
C. Source files can be modified, and a Trojan or backdoor may be included in the source
binaries of some less-known or free distributions of Linux.
D. Only some versions of Linux are available to the public.
11. What command will give you the most information Linux files?
A. ls -a
B. ls -m
C. ls -t
D. ls -l
12. What is the purpose of the man command?
A. Lists help and documentation
B. Manually configures a program
C. Performs system maintenance
D. Installs a program
13. In which directory are Linux system source files located?
A. source
B. src
C. sys
D. system
14. What is the Linux command that lists all current running processes?
A. ps
B. list ps
C. show ps
D. process
15. What is the Linux command for viewing the IP address of a network interface?
A. ifconfig
B. ipconfig
C. ipconfig /all
D. interface /ip
16. Which Linux command would produce the following output?
A. routing
B. route print
C. route
D. show routes
17. What is a recommended way to secure the Linux root account? (Choose all that apply.)
A. Prevent direct root logins except from the system console.
B. Restrict the use of su to a single group.
C. Install su protect to prevent misuse of the su command.
D. Grant the admin privilege to any user needing to install programs.
18. When you are securing local Linux file systems, which two types of directories should you
be check for appropriate permissions? (Choose two.)
A. Root directory
B. Services directory
C. Writable system executable directories
D. Writable user home directories
19. What is the Cat command you would use to harden the file system of a Linux system?
A. Cat “source=All:destination=All”>> /etc/hosts.deny
B. Cat “All:All”>> /etc/hosts.deny
C. Cat “Any:Any”>> /etc/hosts.deny
D. Cat “All:All” /etc/hosts.deny
20. In which file should you check to ensure users do not have a null password in a Linux system?
A. Password file
B. Passwd file
C. Shadow file
D. Shdw file
Answers to Review Questions
1. A. LKM stands for Linux Kernel Module.
2. D. g++ source.cpp –o game is the GCC command to create an executable called game
from the source file source.
3. A. Use the Cat “All:All”>> /etc/hosts.deny command to deny all users access from
the network on a Linux system.
4. C. SUSE, Debian, and Red Hat are all commercial versions of Linux.
5. A. A Linux live CD is a fully functioning operating system that runs from a CD.
6. D. A rootkit can be disguised as an LKM.
7. D. Linux is flexible and can be modified because the source code is openly available.
8. D. Linux should not have unused services running, because each additional service may
have potential vulnerabilities.
9. A. An ISO file is used to create a Linux live CD.
10. C. Known good distributions have been reviewed by the Linux community to verify that a
Trojan or backdoor does not exist in the source code.
11. D. The command ls -l lists all the information about files such as permissions, owners,
size, and last modified date.
12. A. The man command will list help and documentation in Linux.
13. B. The src directory contains the Linux source files.
14. A. The ps command lists all running processes.
15. A. Use the ifconfig command to view the IP address of a network interface. ipconfig
and ipconfig/all are Windows commands to view IP address information.
16. C. route displays the routing table. route print is a Windows command to display the
routing table. show routes is a command commonly used to view a routing table.
17. A, B. The recommended way to secure the Linux root account is to prevent direct root log-
ins and to restrict the use of su to one group.
18. C, D. Writable system executable directories and writable user home directories should
both be checked as they could be used to execute malicious code.
19. B. Use the command Cat “All:All”>> /etc/hosts.deny to harden a Linux system and
ensure all users are denied access to certain files from the network.
20. C. User passwords in a Linux system are stored in the shadow file. To harden a system,
check the shadow file for null passwords.