ethical hacking computer science innovations, llc
TRANSCRIPT
Ethical Hacking
Computer Science Innovations, LLC
Overview
Define Security Discretionary Access Control Trusted Computer System Evaluation
Criteria (TCSEC) - Orange Book 1984 by MITRE Corporation Basis for all we do in Security Define Security, how me measure it.
Long-term goal
Given a System, X, tell me the security level. C2, B1, PL3, PL3+
What does the security level imply? It implies, what you can do with the system. Says Who? Commercial world – Underwriter? What's an Underwriter? Quantify? Insurance Companies.
The Present Situation
If I am Responsible for System, X, how do I bring it into Production?
Someone must Approve. Somebody must assume risk. Who is that? Insurance company DOD Adjudicator. Someone who assumes the risk.
Development up to present
If your system, and you are well defined. If your security model is simple and based
on standards. If you speak the same language as the
decision maker? It is easier to get someone to put their neck
on the line. Einstein said, If I saw further than others it is
because I was standing on the shoulders of Giants.
Goals
Einstein said, As simple as possible, but no simpler.
If you cannot explain it simply, you do not understand it well enough.
Any fool can make things more complex it takes genius to find the simplicity.
Great science is simple.
Science Being Simple
Computer Science – Simple seems to win.
P-V Semaphore --- Seven lines of code.
Google ---- Processing Paradigms....
Simplicity in processing.
Map/Reduce …. Solr...
Open Source......
Definitions
Levels of Security Lowest D... Not even discuss it. Next Level up is C... C1 and C2 C1 and C2 rely on Discretionary Access
Control. Next level up is B1, B2, B3 which are largely
related. B level uses Mandatory Access Control
Use of Definitions
The same definitions are used for Commercial as Government
In other words, there is just one Security. There is Computer Security Used in Different
Areas. What is Discretionary Access Control?
Discretionary Access Control
Concerns itself with Named Subjects accessing Named Objects.
So what is a Subject.... Someone or something wishing to access a computer object.
You accessing your email. The Subject --- You. The Object Email.
What does Concerns Itself with Mean?
Subjects and Objects
Access Control... Can the subject read or write the Object? That is one thing we are concerned with.
Auditing... What did the subject do on June 30th? Who are the subjects that accessed my mail.
Assurance – How can I be Guaranteed that all access to th data have access control and Auditing. And … Does my model work?
Access Control
Access Control has some pieces.... What are the pieces? The first two are Identity Assertion Role Gathering Systems do this. We knew this in 1984.. This is not new and
pre-dates the Internet.
Identity Assertion
Eminem – I am who you say I am. How do you find out your identity? Google... Username and Password Google.. Additional Security through a Token Show Something About yourself Biometric Devices. Prove who you are.
How Do We Do Identity Assertion
Web ServerBrowser
Www.bankofamerica.com
Do
I ha
ve
a se
ssi
on
Do I have a session
How Do We Assert and Identity
Username and Password
Sitekey
Identity Asserter is username and password.
Google --- username and password.
Challenge ---> send a key to cell phone
Biometrics... cheap....
Identity Assertion
Identity Asserters must be pluggable. What does that mean? It means if I change the Identity Asserter, I do
not need to change the software. Best Practice … Run the software with two
different Identity Asserters without changing, compiling or writing Software.
Role Gathering
Browser Web server
Asserts IdentityGathers roles
Role Gathering
Having proven who I am.... What can I do? The Roles Dictate what you can do. So if my role is Administrator.. I can do a lot. If my role is Guest... I can do a little. Show me what you mean. Ok. Let's do a
practical Example.
Where do We See Roles
Web applications.....
Web.xml
Directory ---- roles can work in the directory
Page --- useradmin ----> roles can see it are
Administrator....
Browser... look up web.xml roles..... See it.
Practical Example - Roles
id
uid=1000(scott) gid=1000(scott) groups=1000(scott),27(sudo),30(dip),46(plugdev),109(lpadmin),124(sambashare),129(vboxusers)
Groups are Synonymous with Roles... Spec says.
They say what I can do. Use Plug in Devices Line Printer Administrator, Share Files...etc.
What Happened?
Logged into my machine. Asserted my identity by username password. Gathered my roles. Determined what I can do. Why? It's the standard.
Impromptu Lab
Go to your backtrack instance.
Username root
Password toor
id command
Common Shortcomings?
Let's say you have a machine with a web server.
You have 5 people that are Web Server Administrators
What are your options? You can have a Group Account Or you can setup the machine to allow multiple
people to update the Web Server.
What is Wrong with a Group Account?
It Violates Discretionary Access Control. Why? Named Subject, Named Object. NOT Named Group containing many Subjects and
Named Object. Must be one to one – Person to Subject. Now Three More Topics for C2.
Bringing Up A Web Server
Web Server ---- runs on port 80
Web Server ---- runs on port 8080
Ports < 1024 require Admin Privilege to Start Process.
Ports >= 1024 do not require Admin
Why do we care? Least Privilege....
Have “Normal” Users Web Admin
So Let's say --- Morris Mo... he is a web admin
Cheri is a web admin.... They are going to run
As normal users... But they need to share
The web server.. and we do not want to violate
DAC.. So we need to separate them and
Keep Least Privilege...
Separate Users
Step 1
Create a group per user
And create a shared group.
Mo Al
Webguys shared group.
How To
root@companion:/opt# groupadd mo
root@companion:/opt# groupadd al
root@companion:/opt# groupadd webguys
root@companion:/opt# useradd mo -g mo -G webguys
root@companion:/opt# useradd al -g al -G webguys
root@companion:/opt# useradd mo -g mo -G webguysroot@companion:/opt# useradd al -g al -G webguys
Three More Topics
Confidentiality No one can listen in and gain information. Encryption
Least Privilege Very Very Important. Am I doing the action with the least amount
of Authority. Don't work as Root or Admin Non-Repudiation
How can I not deny that I sent it.
Confidentiality
https Hyper Text Transport Protocol Secure When you read your email are you
http or https? Log into your mail. Is it http or https? https
Least Privilege
I must work as a normal user Or I must work as an admin. Which is better? Why? Myself? Why? You don't mess up the
system on purpose or by accident. Ports... https which port is that? 443 Who do you have to be to work as 443? For ports less than 1024 you must be admin
How Do We Do Least Privilege With https?
The browser (Source) wants to communicate on 443.... Default
The system wants to use a normal user. So what happens? So your Firewall or Router maps 443 to 8443 So the Source requests 443 the System
responds with 8443 the Router maps them. Best Practice … Always map <1024 ports to >
1024 to preserve Least Privilege.
Outside World to Inside
Https in a browser it says communicate on 443
But we want least privilege … So how do we do that.
8443 on the local system.
We need our firewall/router administrator to set this up for us.
Let's Look At This
Web Server8443Browser 443
FirewallAl Admin
Map Incoming443 to intenal 8443 On a specifc Server
Apache and Least Privilege ubuntu@ip-10-204-147-104:~$ ps -ef | grep apache
root 3725 1 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3727 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3729 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3730 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
ubuntu 3828 865 0 14:55 pts/0 00:00:00 grep --color=auto apache
ubuntu@ip-10-204-147-104:~$ sudo su -
root@ip-10-204-147-104:~# cd /etc/
root@ip-10-204-147-104:/etc# grep www-data passwd
www-data:x:33:33:www-data:/var/www:/bin/sh
Apache is not adhering to Least Privilege
Let's Do It
Go to Amazon Web Services. Where .. Google it.
Use Scott's Account [email protected]
lakers Create an Ubuntu 12.04 instance.
Use Backtrack
Go ti VMWare and Start Backtrack Login root toor Type dhclient Type startx Go to firefox Login using your pem key Then go to firefox on backtrack and do http://<amazon.machine.name> You will get …. nothing running
What Happened
Security Group had to have ports 80 and 22 open.
You had to set permission on pem file as 400 meaning only the user can read it.
You ssh -i <pem.filie> ubuntu@<amazon.host.name>
When you go to browser http://<amazon.host.name> nothing
So what are we going to do.. Apache runs.
Next Step – Start Apache
Do an sudo apt-get install apache2 Take the defaults Go to the browser http://<amazon host name> you should see an “It worked!”
What port is it running as? 80
Do a ps -ef | grep apache
root@ip-10-204-147-104:/etc# ps -ef | grep apache
root 3725 1 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3727 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3729 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
www-data 3730 3725 0 14:55 ? 00:00:00 /usr/sbin/apache2 -k start
Who is it Running As?
It was www-data. Who is www-data? Do a grep www-data /etc/passwd What number is associated with www-data? 33 which is less than 1000 which is a root type
user. Do we have least privilege? No. Why? Running as root and using port 80
How For Lab
Classic wizard gives you different ones to choose from. Amazon gives you their own AMI default. Choose an instance of them.
Option to create a new key pair.
Custom TCP rule.
Allow all of 80 8080 22
Then lets launch it.
Need to take a list of it. Need to set the key to get it to log in.
Unix Cheat Sheet
The command ls is the same thing as dir in windows
The command ps is process status and commonly used as ps -ef | more
Do a ps -ef | more The command pwd is print working directory The command chmod is change mode The command chgrp is change user and group
DAC in UNIX
In Unix we get DAC out of the box. How do we do it. Name Subject …. logging in You guys are root/toor – backtrack How do we protect files? This is access control.
Unix History
How did we get to Unix? Who created it? Brian Kerrnighan, Dennis
Ritchie, Thompson. They worked for AT&T in New Jersey in the
70's. They had an idea. What if an operating systems was created that worked on any hardware?
So they needed a hardware independent language – they called it C.
Unix History Continued
AT&T gave it away for free. How many run Android's. Unix kernel How many run IPhones. Unix. There are two flavors. System V – MIT –
Linux BSD – Berkeley – Cal Berkley – Mac/OS AT&T – Created this.
Amazon Unix vs. Windows
Unix and Windows are both available in the Cloud.
The pricing difference is what? Windows is more expensive differing by
licensing costs. Access is a little different.
Commands - Unix
Permissions wwwxxxyyy for a file or directory. Now let's define www it has 3 digit for RWE So RWE is what … 7 now www is for the
user's permission. xxx is for the group's permission and yyy is for the world's permission. So if a file is 400 like .pem file what is that? 400 100 000 000 which is R------ at the owner
level.
More Permissions
So if I want a file to be Read and Write for the Owner (User) of the file and Read for the Group and Nothing for the world.
Let's do it together www xxx yyy U G O The three digits RWE 110 100 000 = 6 4 0
Lab on Permissions
So..... A User may Read Write and Execute. The Group may Read and Write. The Other may only Read. What is the pattern? Remember www xxx yyy RWE U G O 1 1 1 1 10 100 7 6 4
So Back to Commands
The command ls -al full listing. You can see the pattern.
So we a couple more commands and we are done.
The command chmod 3DIGITS files changes the mode. chmod 777 allows all access.
The command chgrp user:group and it lets yo set the owner.
The World of Discretionary Access Control
Says I should have a way to protect my private files.......
Well, let's create two users. Chris and Dave Chris should see Chris files and David could
see Chris files, but only Chris can update Chris files and only Dave can update Dave files.
Let's Do It root@companion:/opt# groupadd class
root@companion:/opt# groupadd dave
root@companion:/opt# groupadd chris
root@companion:/opt# useradd dave -g dave -G class
root@companion:/opt# useradd chris -g chris -G class
So class is a shared group with two members dave and chris.
So, dave has a primary group …. dave
So,, chris has a primary group …. chris
See DAC
Common area and it is call /opt … which is for optional software
The command mkdir makes a directory.
root@companion:/opt# echo "hello" > chris.txt
root@companion:/opt# echo "goodbye" > dave.txt
root@companion:/opt# more chris.txt
hello
root@companion:/opt# more dave.txt
goodbye
root@companion:/opt# ls -al chris.txt dave.txt
-rw-r--r-- 1 root root 6 Jun 25 13:40 chris.txt
-rw-r--r-- 1 root root 8 Jun 25 13:40 dave.txt
Chris and Dave – Private for Writing
Command chown user:group file Command chown chris:chris chris.txt Command chown dave:dave dave.txt Command ls -al *.txt
root@companion:/opt# ls -al *.txt
-rw-r--r-- 1 chris chris 6 Jun 25 13:40 chris.txt
-rw-r--r-- 1 dave dave 8 Jun 25 13:40 dave.txt
root@companion:/opt# su - dave
No directory, logging in with HOME=/
$ cd /opt
Lab
Create a private group for you and your partner along with a shared group.
Create a user for you and your partner with the private group as your primary group (-g) and the shared group (-G) as your supplemental group.
Add each user. Put a file in opt for each user. Use chmod and
chown to make the file globally read but only private write.
Bit Patterns for File Permissions
File www xxx yyy
The first w bit is 4
The next w bit is 2
The last w bit is 1
So if we have 111 what is that 7
So if we have rwe what is that 7
So if we have Read only that is 4
Annoying Cannot Save Backup File
When you are working as a user... you have a private home directory, where you can work.
The command useradd has a way to specify the home directory, which we did not do, so it defaulted to the root of the system which is owned by root. So you cannot write to it.
To Consider
There is an appropriate tool for a job. This is not Religion. We are trying to get a job done. There are 2M LAMP developers worldwide.
Wikipedia – written in LAMP. Bugzilla, written in LAMP.
So, what Computer Scientists say is LAMP is not real computer science. I disagree,
To Consider
There is an appropriate tool for a job. This is not Religion. We are trying to get a job done. There are 2M LAMP developers worldwide.
Wikipedia – written in LAMP. Bugzilla, written in LAMP.
So, what Computer Scientists say is LAMP is not real computer science. I disagree,
We Want To Use Least Privilege
We get our web server (Tomcat) to work as a normal users.
What does this imply?
Port # >= 1024... No privileged User.
Example of this
Google Technology
Starting out... Google ingested the entire web and searches it.
But the technology that ingest the entire web is called Map/Reduce and is the open source Apache project – Hadoop.
The technology to read the entire web is called the Apache project Solr.
Solr
Runs with Least Privilege.
Show me!
Ran Solr:
Accessed it through http://localhost:8080/solr
Did a ps -ef | grep tomcat.
Running as scott
AWS.amazon.com/amis – these are amazon machine images.
Top Down.... A specification committee gets together,,, they understand the need.... they build a specification. Many are good, some are bad.
Bottom up... The specification committees do not know about this. A vendor starts it.... It gets critical mass... It becomes a defacto standard.
Somethings That Came From a Specification
TCP/IP
HTML
Web Archives.
Java.
Browsers.
Some Things not from a Specification (defacto)
Processors on PC
Wiki's
Spring Framework
Social Networking
RESTFull
Amazon - AMI
Amazon Machine Images
https://aws.amazon.com/amis
65,000 different machine machine images.
Ubuntu 12.04, MySQL Apache, php, postfix
Server … Elastic... Managed in a secure way.
Why is this Popular
Speed, efficiency, cost
Shawn – I can bring up a production instance in less than 5 minutes.
Cost – Initial costs are nominal. I pay as I go.
How Do I do This
And, can I learn from them. In other words, what are smarter people than me doing?
First go to amazon ece2. (Elastic Compute Cloud)
classic wizard gives you different ones to choose from. Amazon gives you their own AMI default. Can go out to community and see the ones out there running . Choose an instance of them. Takes the image out there running and takes a copy of it. 12.04 seems to be the sweet spot. Stability. The later ones more experimental. If you're a developer or newer things you may want experimental ones. If setting up a production environment not prudent.
Launched an Instance
I have a security key that I use to get to the server. This is going to lead to a best practice.
scott@companion:~/Desktop$ ls -al elijah.pem
-rw-rw-r-- 1 scott scott 1696 Sep 11 11:13 elijah.pem
scott@companion:~/Desktop$ chmod 600 elijah.pem
scott@companion:~/Desktop$ ls -al elijah.pem
-rw------- 1 scott scott 1696 Sep 11 11:13 elijah.pem
scott@companion:~/Desktop$
Let's Get to our Server
ssh -i elijah.pem [email protected]
So if we do not use a private key
Permission denied (publickey)
Best Practices?
No unencrypted access. Only ssh or https
443 22 80, ports that are open
DAC – Single User to account. Groups. Shared, etc.
And Private key to get into ssh.
LabGo back to Amazon,
Create an instance.
Log on to the server.
Remember.... chmod 400 on the key
Do not lose the key.
Password lakers
Review
Security Levels:
D everything
C1 – DAC with group level
C2 - DAC individual users and objects.
B1 - Mandatory Access Control – Wednesday It is what we need for Multi-level secure.
B2, B3, A1 is the same as B1 with more Assurance.
Review - II
So, how can I prove Solr is running with Least Privilege?
Possibly – it is running on port 8080 >= 1024.
scott@companion:~$ ps -ef | grep tomcat
scott 10139 18578 0 14:55 pts/4 0
User is scott
Command grep scott /etc/passwd
Command su - scott
SQL Injection and Cross-Site Scripting
You have web page..... It has a text box. Your programmer is not very sophisticated, think of a Neanderthal...
The code can be
SQL statement including <text box contents>
Javascript code can be Javascript statement including contents of <text box>
Contents make it do bad things.
Confidentiality
Encrypted - Keeping data confidential.
We believe all communication links between the outside world and our systems shall be encrypted.
Command ssh
Data is considered either active or passive. Active is you are transferring it for use.
Passive is the data is stationary. In a Relational Database Base Management System.
Should Passivated Data Be Encrypted?
This is unsettled science.
So your homework assignment is to reference some opinions on this and state your opinion based on your analysis at 9am tomorrow morning.
Make sense? Remember, active data is encrypted. This is settled science. Passivated is not settled. Valid opinions on both sides.
Fingerprinting
So, we have a file at the top level of a
Web site.
It is called robots.txt
It specifies where to fine content and
What content to avoid.
What can this tell us from a fingerprinting perspective? Tells us the stuff we wish to protect.
Fingerprinting Perspective
Www.walmart.com
Www.schwans.com
Take down the robots.txt
Take down the sitemaps
Try to take down the disallows
Use wget …
For backtrack command line dhclient
Lab Fingerprint Web Server
Use wget
Use wget www.walmart.com/robots.txt
Use more robots.txt
Use wget <sitemap files>
Use more <sitemap files>
Use www.schwans.file
Try to wget disallowed files.
What Did We Learn?
What can we do with robots.txt from a fingerprint perspective. Part of directory structure.
Show's you what they do not want to share.
Why does wget not pull disallow information? Hint man wget . It adhere's to the robots.txt protocol.
How could we get disallowed information? What type of licensing is wget? Open Source. We can get the source. Change it and go after the disallow.
Web Site Fingerprinting
Best Practices:
1) Use robots.txt for things you want found by a search engine and disallow for things you do not want found.
2) Use a tool (if you are a penetration tester) to work around the disallow in robots.txt. Remember disallow is a protocol.
3) Use security in the web server to protect sensitive files.
Network 101
Typically three types of networks A, B, C
Differ by.... netmask
A netmask 255.0.0.0
B netmask 255.255.0.0
C netmask 255.255.255.0
So how does this work.
OSI Networking Model
Application - Applications running on top - ssh
Presentation --- Map data between representations.
Session --- Support conversation.
Transport --- Put stuff in order, end to end
Network – communicate with routing
Data Link --- communicate without routing
Physical --- Cable
Data Link Layer
Data link – no routing
Scott Brian
Command to See Network
Ifconfig -a
Scott
inet addr:10.10.10.234 Bcast:10.10.10.255 Mask:255.255.255.0
Brian ….. 10.10.10.231...
Netmask 255.255.255.0 What does that mean.
Netmask
255.255.255.0 Class C network. Only route if you differ by more than the last
octet. 10.10.10.234 10.10.10.231 No Routing necessary. Only differ by where
the Netmask is 0 therefore resolved at the data link layer. MAC/IP. The conversion between MAC and IP is datalink.
More Netmask
255.255.0.0 is a B network only route if differ by left-most two octets.
192.168.1.2
192.168.2.3
Routing? No. Why? The only values that differ are where you have a bit pattern of 1111's
255.0.0.0 is an A network
10.0.1.7 and 10.1.1.7 does it require routing. Only differs by where it is 1.
Netmask Concluded
Class C network Netmask 255.255.255.0 What is that in HEX?
– FFFF.FFFF.FFFF.0000 What is that in Binary?
– 1111111111111.1111111111111111.111111111111.0
So Class C network one computer is 192.168.1.10 and one is 192.168.1.12 Need Routing?
Netmask Lab
Class C Network 255.255.255.0
– 192.168.1.10 and 192.168.0.11Need routing? Yes. Differs by third
Class A Network 255.0.0.0
– 10.11.1.1 and 10.10.1.1 need routing? no.
– 11.11.1.1. and 10.10.1.2 need routing? yes
Question 192.168.1.1 for a router Cisco– who makes it. 192.168.0.1 – Dlink Netgear, who makes it?
A Little Further in the Network Find the router..
– Unix
– Command netstat -rnscott@kitchen:~$ ifconfig -a
eth0 Link encap:Ethernet HWaddr c8:0a:a9:b5:9d:db
inet addr:192.168.1.2 Bcast:192.168.1.255 Mask:255.255.252.0
scott@kitchen:~$ netstat -rn
Kernel IP routing table
Destination Gateway Genmask Flags MSS Window irtt Iface
192.168.0.0 0.0.0.0 255.255.252.0 U 0 0 0 eth0
169.254.0.0 0.0.0.0 255.255.0.0 U 0 0 0 eth0
0.0.0.0 192.168.1.1 0.0.0.0 UG 0 0 0 eth0
What About DNS?
Domain Name Service. Maps names to IP addresses.
It is given to us by DHCP Unix find it? More /etc/resolv.conf
scott@kitchen:~$ more /etc/resolv.conf
# Generated by NetworkManager
nameserver 192.168.1.1
On My Network
192.168.1.1 is the DNS Server and the Router Netmask is 255.255.252.0 It is CISCO like???? That is what we found out. To do on Windows ipconfig /all
Lab.... Tell me what you have on your Windows box?
Conventions
Class C 255.255.255.0
– Generally 192.168.x.x Class A (bigger network)
Generally 10.x.x.x.
Gateway … generally. What ever you are working with .1 DHCP Server is generally the Gateway.
What is DHCP?
Distributed Hosts Configuration Protocol Turn on a computer, get the IP address, DNS
Server, Router, and any Routes. Broadcasts for it. In other words, comes up, says who is my
DHCP? First one wins.
What is wrong with our Network, via Conventions?
C Network, why netmask 255.255.255.0 IP address starts with 10, which is an A
network Should start with ???? 192.168 Router ends in .254, what does it typically do?
– .1
Review Fingerprinting Why do we Fingerprint? To learn about the
system. If you are an adversary, you want to find something easy.
If you are a security professional, you want to see how hard your systems are.
Most common tool is nmap. Nmap can help you work around an IDS. Inspects traffic to tell you about products and
ports. Nmap is a TCP/IP expert, Xmas, Stealth,
etc.
Network use Netmask
Typical network --- cisco …
Ip address of the router is
192.168.1.1
255.255.255.0
C
So if I talk to 192.168.1.10 to 192.168.1.21
Do I need to route?
No?
So if the address differs by the octet with a 0 in the netmask no routing.
Network Route When
Addresses differ from where there is a 1.
For 255.255.255.0
If we wish to go from 192.168.1.10 to 206.245.1.17
Do we need to route? Yes
How do we find our router? Use netstat -rn
Talk About Addresses
TCP/IP protocol
We agree to not route what addresses:
169.254 what you get when you do not get a dhcp address.
172.
10.
192.168
127.0.0.1 127.0.0.2
192.168.1.x CISCO
192.168.0.x DLINK
Network Topology
So, I want three networks to be separate and have one external address to the internet. How do I do this?
206.1.17.9 external address 10.10.10.254 internal
Network1 192.168.1.x 255.255.255.0 gtw 192.168.1.1
Internal (10.10.10.1)
Network2 192.168.2.x 255.255.255.0 gtw 192.168.2.1
Internal (10.10.10.2)
Network3 192.168.3.x 255.255.255.0 gtw 192.168.3.1
Internal (10.10.10.3)
What Did We Learn
1) Netmask determines your address range.. Route when difference is in the area of 1's on netmask.
2) Router must be on same subnet as network it is routing.
3) How do we find netmask Unix (ifconfig -a) windows ipconfig /all
4) How do we find router – netstat -rn
5) How do we find dns server windows its ipconfig /all
Use more /etc/resolv.conf
Email Tracking
Let's say, I sent an email to Mo and I wanted assurance that he has read it. Email itself is a datagram.
In the email message
<img src=”www.morrisisagreatguy.com/photo.jpg”>
Tools that do this for you. Put a link that does not require a click and sends that to a server for recordiing.
Fingerprinting Lab
Tell me what I am running at www.scottstreit.com
By using nmap
Tell me what hosts on your subnet are running.
By using nmap
Lab
Create a private group for you and your partner along with a shared group.
Create a user for you and your partner with the private group as your primary group (-g) and the shared group (-G) as your supplemental group.
Add each user. Put a file in opt for each user. Use chmod and
chown to make the file globally read but only private write.
Review and Talk About Today
Discretionary Access Control
Go through nmap
DAC – Step by Step lab.
For nmap – two videos from youtube.
DAC
Why do we care how this works?
Unix paradigm is everywhere
Old people like Scott we had Unix with no commands. So we manually modified two files /etc/group and /etc/passwd
This impacted or effected the behavior.
Ubuntu/debian Fedora/RedHat... they have different commands … but they all impact /etc/group /etc/passwd
Commands
We have useradd, groupadd, umask, chmod, chown --- five commands to do all of it.
1) Group out there. So you need private group which means the username is the same as the group name. So you need one of these per user, and one shared group.
root@companion:~# groupadd dhoward
root@companion:~# groupadd snash
root@companion:~# groupadd lakers
What Happened Here?
We have two new Lakers as we move towards our 17th NBA Championship, Dwight Howard and Steve Nash. So if we wish to add them we need to add the private group first. Next we need a shared group... Lakers.
How do we check this
We can do a tail /etc/group
dhoward:x:1004:
snash:x:1005:
lakers:x:1006:
What do We do Next
Create the users
Do useradd snash -g snash -G lakers
root@companion:~# useradd snash -g snash -G lakers
root@companion:~# useradd dhoward -g dhoward -G lakers
What Happened
root@companion:~# tail /etc/group
dhoward:x:1004:
snash:x:1005:
lakers:x:1006:snash,dhoward
We have dhoward and snash are private. The group lakers has two supplemental users snash and dhoward.
What do we do Next?
Create a shared area on disk.
Going to go to /opt create a directory called seventeen. In there I want to share files.
root@companion:~# mkdir /opt/seventeen
root@companion:~# cd /opt/seventeen
root@companion:/opt/seventeen# ls -al
total 8
drwxr-xr-x 2 root root 4096 Sep 11 09:31 .drwxr-xr-x 2 root root 4096 Sep 11 09:31 .
drwxr-xr-x 4 root root 4096 Sep 11 09:31 ..
drwxr-xr-x 2 root root 4096 Sep drwxr-xr-x 2 root root 4096 Sep 11 09:31 .11 09:31 .
What is wrong with this. Group cannot write to it. That is wrong because we want the group to share it. Why did it default to 755 for permissions.
We have rwe rwe rwe
111 101 101
This implies a umask of 22. Umask, as the name implies (mask) are the 0's for file creation.
Command umask
The command umask with no parameters gives us the mask – user mask. Or with a parameter, changes it. So we want what umask.
We want rwe rwe rwe
111 111 101
What umask 002
root@companion:/opt/seventeen# umask
0022
root@companion:/opt/seventeen# touch z
root@companion:/opt/seventeen# ls -al z
-rw-r--r-- 1 root root 0 Sep 11 09:35 z
root@companion:/opt/seventeen# umask 002
root@companion:/opt/seventeen# touch y
root@companion:/opt/seventeen# ls -al y
-rw-rw-r-- 1 root root 0 Sep 11 09:38 y
Ownership, directories and files
Rules for ownership.
Is am Unix and my default behavior is
Create a file with the user being the user creating it the group being the user's primary group and the permissions are determined by the umask.
root@companion:/opt/seventeen# chown snash:lakers /opt/seventeen
root@companion:/opt/seventeen# su - snash
No directory, logging in with HOME=/
$ cd /opt/seventeen
$ touch t
$ umask
0002
$ ls -al t
-rw-rw-r-- 1 snash snash 0 Sep 11 09:41 t
-rw-rw-r-- 1 snash snash 0 Sep 11 09:41 t
We have a problem.... really is major, which is the file is owned by the primary group not the shared group.
We cannot fully share the file across dhoward and snash so let's revisit our rule.
Rule
When a user creates a file...... the file has the owner as the user and the group is the directory above if the sticky bit is set... or the primary group.... if the sticky bit is not set... So how do we set the sticky bit.
We user chmod 2775 /opt/seventeen
The Sticky Bit
root@companion:/opt/seventeen# chmod 2775 /opt/seventeen
root@companion:/opt/seventeen# su - snash
No directory, logging in with HOME=/
$ cd /opt/seventeen
$ touch zzz
$ ls -al zzz
-rw-rw-r-- 1 snash lakers 0 Sep 11 09:46 zzz
What Do We Have Here
Posix compliant Discretionary Access Control.
It comes... out of the box..... No add on packages, no recompiles, and it is constant protection.
We say, linux, out of the box is C2 capable.
We say it is capable, why?
C2 Capable
Anyone can take a C2 system and make it D. If you have a group account and multiple people log in using the same account … you are now at D.
PL3, PL3+ … C1, C2
PL3 = C2
PL3+ = B1
Passive Encryption vs. Active
Read the Orange book, there standards that say passivated data must be encrypted B1...
We largely do not do this.... Is this good or bad and why?
Encrypting Passivate Data is Good
Handle the case of the disk falling into the wrong hands. Could argue, encrypting a laptop hard drive.
Tiered Security.... Encryption at the Xmission level and at the storage level.
Encrypting Passivated Data is Bad
1) We typically do not guard against physical access. Guns, Guards, Gates.
2) What if you loose the key.
3) None of our tools run on encrypted data.
So if you have encrypted data in a mysql table, you have to write the encryption/decryption layer..... so the costs of software development goes up dramatically.
Reasonable Compromise
Highest risk data is encrypted.. which means lap top data is encrypted. Why? No penalty. And you are much more likely to lose a lap top then a bad person grabbing control of your machine. This is where we are today.
Fingerprinting
We want to see what is on our network. If you are bad.... then you are looking for easy
things. We want to make sure, we are not one of
those easy things. So for Bad People, Fingerprinting is a way to
find easy systems to crack. For Security Professionals, hardening our
systems.
Best Practices
Only SSH login and only through a private key. Open Ports 22 (private key only) and 443 This is for externally facing Servers So how do we find out?
How Do We Fingerprint
Command - telnet host port Then send it commands Then get what's running by parsing the results
of commands.
scott@companion:~$ telnet www.scottstreit.com 80
Trying 74.103.6.161......
HEAD
<address>Apache/2.2.14 (Ubuntu) Server at localhost Port 80</address>
</body></html>
Instead Of
Telnet to a port. Writing a socket level program Ping
scott@companion:~$ ping www.scottstreit.com
PING www.scottstreit.com (74.103.6.161) 56(84) bytes of data.
64 bytes from pool-74-103-6-161.bltmmd.fios.verizon.net (74.103.6.161): icmp_req=1 ttl=52 time=24.7 ms
We Use Nmap
What is good about Nmap? Price.... Free Runs on every system. Around a long time – stable. Defacto Standard. Does a lot of things.
nmap
We can see what systems are up on a subnet We can see what ports are open We can see what tools are runinng on the
open ports. We don't have to fool around with TCP/IP
Two Movies on nmap
Let's watch two youtube videos on nmap.
Lab Tell me what is running on my machine. Www.scottstreit.com Do it two ways. First telnet port HEAD port 80. Telnet www.scottstreit.com 80
– HEAD Then do an nmap on my box. Tell me what is running. Tell me what hosts are up on our 10. subnet. Use your backtrack instance Google it.
Let's Simulate nmap
scott@companion:~$ telnet www.scottstreit.com 80
Trying 173.59.254.127...
Connected to www.scottstreit.com.
Escape character is '^]'.
head
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>501 Method Not Implemented</title>
</head><body>
<h1>Method Not Implemented</h1>
<p>head to /index.html not supported.<br />
</p>
<hr>
<address>Apache/2.2.14 (Ubuntu) Server at localhost Port 80</address>
</body></html>
Connection closed by foreign host.
scott@companion:~$