Chapter 10: Securing Your System

Question 1

Super daemon

Answer 1

A program that listens for network connections for another program. As soon as the connection is initiated, the super daemon gives control of the connection to the intended server.

Question 2

What are the two primary super daemons?

Answer 2

<b>inetd</b>

xinetd</b>

Question 3

<b>inetd</b>

Answer 3

The legacy super daemon in Linux. You probably won’t ever see it, except on the Linux+ test. Learn more on 526

Question 4

TCP Wrappers

Answer 4

It checks whether a client is authorized to access a server, and if it is, it calls the server program. Learn more on 527.

Question 5

<b>xinetd</b>

Answer 5

Extended super daemon. It has all the functionality of <b>inetd</b>, plus security options similar to TCP Wrappers. Learn more on 528-529.

Question 6

What program can be used to configure packet filter firewall settings?

Answer 6

<b>iptables</b>

Question 7

<b>netstat</b>

Answer 7

The best way to begin auditing your network security. You can look at network activity and open ports to see what exactly is going on. Learn more on 531.

Question 8

<b>lsof</b>

Answer 8

Nominally lists open files, who’s accessing them, etc. Learn more on 534.

Question 9

<b>nmap</b>

Answer 9

This is a network scanner. It can look around at all the open ports on your computer or on others. It’s very easy to use and very powerful. Learn more on 536.

Question 10

<b>fuser</b>

Answer 10

Another port auditing tool that’s really good for determining processes currently using a particular port.

<b>$ sudo fuser 22/tcp</b>

Learn more on 538.

Question 11

What options do you have for shutting down an unnecessary server?

Answer 11

You can disable the server by changing its startup script, or disabling the daemon’s configuration files.

You can also completely uninstall the server using the package management tools or by just deleting its files by hand.

Question 12

REMEMBER GOOD PASWORD RULES

Answer 12

We learned this shit in Security+

Question 13

Tools for password management

Answer 13

You can use <b>usermod</b> to adjust shadow password features. <b>chage</b> is more thorough for some of these security features.

Question 14

If a user is complaining about specific problems and you want to look at them from their perspective, how can you do that?

Answer 14

As <b>root</b>, you can use the <b>su</b> command to switch to another user, i.e. acquire their privileges.

Question 15

<b>sudo</b>

Answer 15

This command lets you run a single command as <b>root</b>. This is much more secure than just logging in to a session as root.

Question 16

What is repudiation?

Answer 16

You can’t really prove who may be at fault. If you’re logged in as <b>root</b>, no one can prove that you were up to the no good that went on.

Question 17

<b>who</b>

Answer 17

This command shows you everyone who’s currently logged onto a system. Using the <b>-a</b> modifier will give you a lot of more useful information.

Question 18

How can you determine who was last logged into the system?

Answer 18

<b>last</b>