This PPT consist of What is Network, Active & Passive Threats, Network basics, Network Scanning, Different types of attacks, Firewall Configuration, IDS, DDoS, DoS attacks

1. Network Security &
System Admin
Presented By :
Md Sahabuddin
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NETWORK SECURITY
• Information & Network penetration do occur
- from outsiders & insiders
in spite of having various security measures
such as Anti-virus, Firewalls, Routers
• There are two ways to attack computers
- Gain physical access to machines & conduct
physical attack
- Attack by use of malicious software; Malware

3. Organization
 What is Security all about?
 What is at Risk?
 Why Risks Exist?
 General Threat Perceptions
 Security
 Data (local, Remote)
 Communications
 Secure Backup
 Network Perimeter Security
 General Policy
 Min. Security Enforcement
 Intrusion Detection System
 Cryptographic Security
 VPN: A Roadmap
 Points for Action
 Emergency Response Team
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4. Who is vulnerable?
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Security Goals
Confidentiality
Integrity
Avalaibility

6. What is Security all about?
 Confidentiality:
 Protecting sensitive information from unauthorized
disclosure or intelligible interception; Only seen by
entities to whom it is addressed
 Integrity:
 Not modified/destroyed in a unauthorized way;
safeguarding the accuracy & completeness of information
& software
 Access Control:
 Access (computation, data, service) follows the prescribed
policy
 Authentication:
 Verifying the identity claimed
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7. Contd.
 Availability:
 System accessible/usable on demand
 Nonrepudiation:
 Protection against false denial of comm.
 Audit Trail:
 Chronological record of system activities to enable
reconstruction/examination of environments/activities
leading to an operation from inception to final results.
 Privacy:
 Breach of confidentiality is also invasion of privacy.
 Collecting a dossier based upon his activities - inferring
habits, movements, expenditures  Security Risk
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8. Active and Passive Threats
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9. Common security attacks
and their countermeasures
 Finding a way into the network
 Firewalls
 Exploiting software bugs, buffer overflows
 Intrusion Detection Systems
 Denial of Service
 Ingress filtering, IDS
 TCP hijacking
 IPSec
 Packet sniffing
 Encryption (SSH, SSL, HTTPS)
 Social problems
 Education
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10. General Threat Perceptions
 Network threatened by external running
malicious scripts (Malware)
 Adversaries attempting access protected
services, break into machines, snoop
communications, collect statistics of
transactions …
 Insiders and outsiders
 Disasters (natural and man-made)
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11. Secure Storing of Data
(Local Storage)
 Physical Security
 Protect machine
 Limit network access
 Most secure (without
external access)
 Suppose it falls into
an adversary
 All the data can be
obtained in the clear
 Cryptographic Secure.
 Protects even if the m/c
falls to adversary
 Of course person having
access can delete --
Hence, BACKUP
 Data Integrity
 Cryptography: Fragile
 System issues, user
interfaces , Crypto-file
servers …
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12. Eternal Blue Attack
 EternalBlue exploits a vulnerability in Microsoft's
implementation of the Server Message Block (SMB)
protocol. This vulnerability is denoted by entry CVE-
2017-0144 .
 Execution of Attack.
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19. Network Scanning
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21. Closing Open Ports
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25. Firewalls
 A firewall is like a castle with a drawbridge
 Only one point of access into the network
 This can be good or bad
 Can be hardware or software
 Ex. Some routers come with firewall
functionality
 ipfw, ipchains, pf on Unix systems, Windows
XP and Mac OS X have built in firewalls
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26. Firewall
 Used to filter packets based on a combination
of features
 These are called packet filtering firewalls
 There are other types too, but they will not be discussed
 Ex. Drop packets with destination port of 23
(Telnet)
 Can use any combination of IP/UDP/TCP header
information
 man ipfw on unix47 for much more detail
 But why don’t we just turn Telnet off?
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27. Firewall
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Intranet
DMZInternet
Firewall
Firewall
Web server, email
server, web proxy,
etc

28. Firewall
 Here is what a computer with a default
Windows 7 install looks like:
 135/tcp open loc-srv
 139/tcp open netbios-ssn
 445/tcp open microsoft-ds
 1025/tcp open NFS-or-IIS
 3389/tcp open ms-term-serv
 5000/tcp open UPnP
 Might need some of these services, or might
not be able to control all the machines on the
network
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29. Configuring Windows Firewall
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35. DoS (Denial of Service)
 Purpose: Make a network service
unusable, usually by overloading the
server or network
 Many different kinds of DoS attacks
 SYN flooding
 SMURF
 Distributed attacks
 Mini Case Study: Code-Red
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36. Denial of Service
 SYN flooding attack
 Send SYN packets with bogus source address
 Why?
 Server responds with SYN ACK and keeps state
about TCP half-open connection
 Eventually, server memory is exhausted with this state
 Solution: use “SYN cookies”
 In response to a SYN, create a special “cookie” for the
connection, and forget everything else
 Then, can recreate the forgotten information when the
ACK comes in from a legitimate connection
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37. Denial of Service
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Internet
Perpetrator Victim
ICMP echo (spoofed source address of victim)
Sent to IP broadcast address
ICMP echo reply

38. Smurf Attack
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39. Intrusion Detection Systems
 Attack detection, with automated response
 Damage prevention and containment
 Tracing and isolation of attack origin points
 Used to monitor for “suspicious activity” on a
network
 Can protect against known software exploits, like buffer
overflows
 Open Source IDS: Snort, www.snort.org
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40. Intrusion Detection
 Uses “intrusion signatures”
 Well known patterns of behavior
 Ping sweeps, port scanning, web server indexing, OS
fingerprinting, DoS attempts, etc.
 However, IDS is only useful if contingency
plans are in place to curb attacks as they are
occurring
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41. Snort Configuration
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43. Black & White List
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46. WPA 2 (Wi-Fi Protected Access 2 )
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Wi-Fi Protected Access 2 is a network
security technology commonly used on Wi-Fiwireless
networks. It's an upgrade from the
original WPA technology, which was designed as a
replacement for the older and much less secure WEP.
WPA2 is used on all certified Wi-Fi hardware since 2006 and is
based on the IEEE 802.11i technology standard for data
encryption.
Cracking WPA 2 Network :

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53. DDoS (Distributed Denial of Service)
 DDoS is a type of DOS attack where multiple
compromised systems, which are often infected with
a Trojan, are used to target a single system causing
aDenial of Service (DoS) attack.
 Victims of a DDoS attack consist of both the end targeted
system and all systems maliciously used and controlled
by the hacker in the distributed attack.
 The DDoS attack uses multiple computers and Internet
connections to flood the targeted resource. DDoS attacks
are often global attacks, distributed via botnets.
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54. Execution of DDoS Attack
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Security related URLs
 http://www.robertgraham.com/pubs/netwo
rk-intrusion-detection.html
 http://online.securityfocus.com/infocus/152
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 http://www.snort.org/
 http://www.cert.org/
 http://www.nmap.org/
 http://grc.com/dos/grcdos.htm
 http://lcamtuf.coredump.cx/newtcp/

62. THANK YOU
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