1. Nertwork Security

2. Security in the networks
Bank fraud
Politics
Stealing credit card numbers
Commercial espionage
Hacktivism
Cracker “having fun”
Changing grades
Wars (Cyberwarfare)
SHARE or PROTECT?

3. Goals of Security Confidentiality Integrity Availability
Only authorized entities have access to a system
Integrity
The information can be altered in an authorized and in acceptable manner
Availability
Services and data can be accessed by authorized users and processes when they need them

4. Goals of Security
Confidentiality
Integrity
Availability
SECURE

5. Balance is not easy
Connectivity
Performance
Easy to use
Manegeable
Availability
Authentication
Authorization
Accounting
Confidentiality
Integrity

6. Key elements

7. It is not all about hardware and software
“...no product or combination of products will create a secure organization by itself. Security is a process; there is no tool that you can 'set and forget'. All security products are only as secure as the people who configure and maintain them...”
John Mallery (BKD, LLP)
Security is a process not a product
Bruce Schneier

8. These days are long gone

9. Vulnerable networks Anonymity Multiple points of attack Sharing
Sources and targets
Sharing
Many authorized users
Many systems
Complex systems
Designed without security in mind (ie: Desktop)
Confused perimeters
No borders
Multiple routes and unknown
Internet
Protocols

10. Technological weaknesses
Protocols
TCP/IP 1981
Operating Systems
Devices
Wireless
802.11
Bluetooth

11. Configuration weaknesses
Unsafe user accounts
Weak passwords
Not properly configured Internet services
Default configuration
Bad configuration/administration of network devices

12. Processes and Policies weaknesses
Not well written and described policies
Lack of continuity
Access controls not applied
Careless instalation of software and hardware
Absence of a Distater Recovery Plan

13. Attack: Preliminary steps

14. Reconnaissance
Militar and medical term
Exploration to obtain information
Before any attack
Obtain as much information as possible of the victim
Many ways to do this …....
….. and not all are technical

15. Reconnaissance: Port scanning
Check which ports are open in a machine
Services with network connection
Other valuable information
Operating System
Application versions
Nmap, netcat, scapy, etc

16. Reconnaissance: Social Engineering
Port scanning give an external view
Social Engineering gives an internal point of view
Passwords
IP addresses
Dates
Acting skills
Simpathy, pity, fear, etc.

17. Reconnaissance: Intelligence Gathering
“Dumpster diving”
Network diagrams
Code
Server, routers configuration
Eavesdropping
Machines and people

18. Reconnaissance: Intelligence gathering
Forums
People ask questions
I have a X 2.3 server. How I configure the Web service?
Documentation
Manufacters make it available on line

19. Reconnaissance: Identification
Fingerprinting
Operating Systems and applications
Maker, version
Operating System
Each TCP/IP is different
Standards specify the WHAT no the HOW
Tools
Nmap, nessus, netcat

20. Spoofing Situation in which one person, program or
Machine successfully masquerades as
another by falsifying data and thereby gaining
an illegitimate advantage

21. Quick TCP/IP Review
(Internet)

22. Do you Identify these attacks? How do carry them out?
Denial Of Service (DOS)
Ping of Death
SYN Flood

23. Communication
Internet

24. Communication
Internet

25. TCP/IP Transmission Control Protocol/Internet Protocol
Several protocolos
Stack, Suite
Neurological system of the Internet
Designed more than 30 years ago
To understand vulnerabilities and attacks

26. OSI & TCP/IP models IP

27. TCP/IP addresses
Procesos
SCTP
TCP
UDP IP
Acceso al medio

28. TCP/IP Addresses MAC (Layer 2) Identifies a machine in a local network
48 bit number C4:FA:55:6B:C2:76
IP (layer 3)
Identifies a machine in the Internet
32 bit number
Puerto (Layer 4)
Identifies an application running in a machine
16 bit numbre

29. Communication in a local network
Forouzan TCP/IP

30. Communication in Internet
Forouzan TCP/IP

31. ARP (Address Resolution Protocol)‏
Forouzan TCP/IP

32. In the Net ….. Data Hello world! FCS Dest MAC Dest Port Source Dest IP

33. PDU (Protocol Data Unit)‏

34. IP (Internet Protocol)‏
Connectionless protocol
Send independent packets
Datagrams
No guarantee of delivery
“best effort”
Each packet is routed independently of others
Eventhough they belong to the same message

35. IP Header
Forouzan TCP/IP

36. Fragmentation IP Datagram (maximum length = 65535 bytes)
Header
Trailer
Layer 2 data (Ethernet, wif, etc)

37. MTU (Maximum Transfer Unit)
Token Ring (16 Mbps) → bytes
Token Ring (4 Mbps)) → bytes
PPP → 296 bytes
Ethernet → bytes
→ bytes

38. Fragmentation

39. Process to process communication
Internet

40. Operating System and TCP/IP Stack
Applications and Port Numbers
Operating System and TCP/IP Stack
App 1
Port
176
App 2
8176
App N
32675
Data
Port #
Data
IP dest
addr
Port #
Data

41. TCP Header
Forouzan TCP/IP

42. TCP connection establishment
3 way handshake

43. TCP Connection Termination
Four way handshake

44. UDP (User Datagram Protocol)‏
Connectionless protocol
Each segment is idependent
Eventhough they can belong to the same message
No guarantee of delivery
No overhead due to timers and ACKs
Faster than TCP
Designed for applications where partial loss of data is not relevant

45. UDP Header
Forouzan TCP/IP

46. Scope of IP and TCP
Internet