Quiz
Libro T10 - Securing Your System
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Questions in this quiz (20)
1Typing lsof -i | grep LISTEN as root produces three lines of output, corresponding
to the sendmail, sshd, and proftpd servers. What can you conclude about the security of
this system?- AA. Everything is OK; the presence of sshd ensures that data are being encrypted via SSH.
- BB. The sendmail and sshd servers are OK, but the FTP protocol used by proftpd is
insecure and should never be used. - CC. The sendmail server should be replaced by Postfix or qmail for improved security, but
sshd and proftpd are fine. - DD. Because sendmail and proftpd both use unencrypted text-mode data transfers,
neither is appropriate on a network-connected computer. - EE. No conclusion can be drawn without further information; the listed servers may or
may not be appropriate or authentic.
2As part of a security audit, you plan to use Nmap to check all of the computers on your
network for unnecessary servers. Which of the following tasks should you do prior to
running your Nmap check?- AA. Back up /etc/passwd on the target systems to eliminate the possibility of it being
damaged. - BB. Obtain the root passwords to the target systems so that you can properly configure
them to accept the Nmap probes. - CC. Obtain written permission from your boss to perform the Nmap sweep.
- DD. Configure /etc/sudoers on the computer you intend to use for the sweep, to give
yourself the ability to run Nmap. - EE. Disable any firewall between the computer that’s running Nmap and the servers you
intend to scan.
- AA. Back up /etc/passwd on the target systems to eliminate the possibility of it being
3Your login server is using PAM, and you want to limit users’ access to system resources.
Which configuration file will you need to edit?- AA. /etc/limits.conf
- BB. /etc/pam/limits.conf
- CC. /etc/security/limits.conf
- DD. /etc/security/pam/limits.conf
- EE. /usr/local/limits.conf
4Which of the following tools might you use to check for open ports on a local computer?
(Select three.)- AA. Nmap
- BB. netstat
- CC. lsof
- DD. portmap
- EE. services
5Which of the following commands will locate all of the program files on a computer on
which the SUID bit is set?- AA. find / -type SUID
- BB. find / -perm +4000 -type f
- CC. find / -perm +SUID -type f
- DD. find / -type +4000
- EE. find / -suid
6The /etc/sudoers file on a computer includes the following line. What is its effect?
%admin ALL=(ALL) ALL- AA. Members of the admin group may run all programs with root privileges by using sudo.
- BB. Users in the admin user alias, defined earlier in the file, may run all programs with
root privileges by using sudo. - CC. The admin user alias is defined to include all users on the system.
- DD. The admin command alias is defined to include all commands.
- EE. The user admin may run all programs on the computer as root by using sudo.
7Which command would you type, as root, to discover all the open network connections on
a Linux computer?- AA. lsof -c a
- BB. netstat -ap
- CC. ifconfig eth0
- DD. nmap -sT localhost
- EE. top -net
8A server/computer combination appears in both hosts.allow and hosts.deny. What’s the
result of this configuration when TCP wrappers runs?- AA. TCP wrappers refuses to run and logs an error in /var/log/messages.
- BB. The system’s administrator is paged to decide whether to allow access.
- CC. hosts.deny takes precedence; the client is denied access to the server.
- DD. hosts.allow takes precedence; the client is granted access to the server.
- EE. The client is granted access to the server if no other client is currently
accessing it.
9When is the bind option of xinetd most useful?
- AA. When you want to run two servers on one port
- BB. When you want to specify computers by name rather than IP address
- CC. When xinetd is running on a system with two network interfaces
- DD. When resolving conflicts between different servers
- EE. When xinetd manages a DNS server program
10You’ve discovered that the Waiter program (a network server) is running inappropriately
on your computer. You therefore locate its startup script and shut it down by removing that
script. How can you further reduce the risk that outsiders will abuse the Waiter program?
(Select two.)- AA. By blocking the Waiter program’s port using a firewall rule
- BB. By reading the Waiter program’s documentation to learn how to run it in
stealth mode - CC. By tunneling the Waiter program’s port through SSH
- DD. By uninstalling the Waiter package
- EE. By uninstalling any clients associated with Waiter from the server computer
11You want to use xinetd access controls to limit who may access a server that’s launched via
xinetd. Specifically, only users on the 192.168.7.0/24 network block should be able to use
that server. How may you do this?- AA. Enter hosts_allowed = 192.168.7.0/24 in the /etc/xinetd.conf
configuration file for the server in question. - BB. Enter only_from = 192.168.7.0/24 in the /etc/xinetd.conf configuration file
for the server in question. - CC. Enter server : 192.168.7. , where server is the server’s name, in the /etc/
hosts.allow file. - DD. Enter server : 192.168.7. , where server is the server’s name, in the /etc/
hosts.deny file. - EE. Type iptables -L 192.168.7.0 to enable only users of 192.168.7.0/24 to access
the server.
- AA. Enter hosts_allowed = 192.168.7.0/24 in the /etc/xinetd.conf
12Of the following, which is the best password?
- AA. Odysseus
- BB. iA71Oci^My~~~~~~
- CC. pickettomato
- DD. Denver2Colorado
- EE. 123456
13Which of the following types of attacks involves sending bogus email to lure unsuspecting
individuals into divulging sensitive financial or other information?- AA. Phishing
- BB. Script kiddies
- CC. Spoofing
- DD. Ensnaring
- EE. Hacking
14Ordinary users report being unable to log onto a computer, but root has no problems doing
so. What might you check to explain this situation?- AA. A misbehaving syslogd daemon
- BB. A login process that’s running as root
- CC. The presence of an /etc/nologin file
- DD. The presence of an SUID bit on /bin/login
- EE. Inappropriate use of shadow passwords
15Which servers might you consider retiring after activating an SSH server? (Select two.)
- AA. SMTP
- BB. Telnet
- CC. FTP
- DD. NTP
- EE. Samba
16You find that the ssh_host_dsa_key file in /etc/ssh has 0666 (-rw-rw-rw-) permissions.
Your SSH server has been in operation for several months. Should you be concerned?- AA. Yes
- BB. No
- CC. Only if the ssh_host_dsa_key.pub file is also world-readable
- DD. Only if you’re launching SSH from a super server
- EE. Only if you’re using a laptop computer
17For best SSH server security, how should you set the Protocol option in /etc/ssh/
sshd_config?- AA. Protocol 1
- BB. Protocol 2
- CC. Protocol 1,2
- DD. Protocol 2,1
- EE. Protocol *
18Why is it unwise to allow root to log on directly using SSH?
- AA. Disallowing direct root access means that the SSH server may be run by a non-root
user, improving security. - BB. The root password should never be sent over a network connection; allowing root
logins in this way is inviting disaster. - CC. SSH stores all login information, including passwords, in a publicly readable file.
- DD. When logged on using SSH, root’s commands can be easily intercepted and duplicated
by undesirable elements. - EE. Somebody with the root password but no other password can then break into
the computer.
- AA. Disallowing direct root access means that the SSH server may be run by a non-root
19You’ve downloaded a GPG public key from a website into the file fredkey.pub. What must
you do with this key to use it?- AA. Type inspect-gpg fredkey.pub.
- BB. Type gpg --readkey fredkey.pub.
- CC. Type import-gpg fredkey.pub
- DD. Type gpg --import fredkey.pub.
- EE. Type gpg-import fredkey.pub
20You want to send an encrypted message to an email correspondent. You both have GPG.
What do you need to exchange before you can send your encrypted message?- AA. Your correspondent must obtain your GPG public key.
- BB. Your correspondent must obtain your GPG private key.
- CC. You must exchange private keys with your correspondent.
- DD. You must obtain your correspondent’s GPG private key.
- EE. You must obtain your correspondent’s GPG public key.
Information
- Description
- ✓ 1.110.1 Perform security administration tasks ✓ 1.110.2 Set up host security ✓ 1.110.3 Securing data with encryption
- Author
- Victor Rodriguez
- Language
- Español
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- 54
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