Network Security

AttacksTechnical Solutions

AcknowledgmentsMaterial is sourced from: CISA® Review Manual 2011, © 2010, ISACA. All rights reserved. Used by

permission. CISM® Review Manual 2012, © 2011, ISACA. All rights reserved. Used by

permission. Many other Network Security sources http://www.csrc.nist.gov/publications/drafts/800-118/draft-sp800-118.pdf

Author: Susan J Lincke, PhDUniv. of Wisconsin-Parkside

Reviewers/Contributors: Todd Burri, Kahili Cheng

Funded by National Science Foundation (NSF) Course, Curriculum and Laboratory Improvement (CCLI) grant 0837574: Information Security: Audit, Case Study, and Service Learning.

Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and/or source(s) and do not necessarily reflect the views of the National Science Foundation.

ObjectivesThe student should be able to:Define attacks: script kiddy, social engineering, logic bomb, Trojan horse, phishing, pharming, war driving, war dialing, man-in-the-middle attack, SQL injection, virus, worm, root kit, dictionary attack, brute force attack, DOS, DDOS, botnet, spoofing, packet reply.Describe defenses: defense in depth, bastion host, content filter, packet filter, stateful inspection, circuit-level firewall, application-level firewall, de-militarized zone, multi-homed firewall, IDS, IPS, NIDS, HIDS, signature-based IDS, statistical-based IDS, neural network, VPN, network access server (RADIUS/TACACS), honeypot, honeynet, hash, secret key encryption, public key encryption, digital signature, PKI, vulnerability assessmentIdentify techniques (what they do): SHA1/SHA2, MD2/MD4/MD5, DES, AES, RSA, ECC.Describe and define security goals: confidentiality, authenticity, integrity, non-repudiationDefine service’s & server’s data in the correct sensitivity class and roles with accessDefine services that can enter and leave a networkDraw network Diagram with proper zones and security equipment

The Problem of Network Security

The Internet allows an attacker to attack from anywhere in the world from their home desk.

They just need to find one vulnerability: a security analyst need to close every vulnerability.

Hacking NetworksPhase 1: Reconnaissance Physical Break-In Dumpster Diving Google, Newsgroups,

Web sites Social Engineering

Phishing: fake email Pharming: fake web pages

WhoIs Database & arin.net

Domain Name Server Interrogations

Registrant: Microsoft Corporation One Microsoft Way Redmond, WA 98052 US

Domain name: MICROSOFT.COM

Administrative Contact: Administrator, Domain domains@microsoft.com One Microsoft Way Redmond, WA 98052 US +1.4258828080 Technical Contact: Hostmaster, MSN msnhst@microsoft.com One Microsoft Way Redmond, WA 98052 US +1.4258828080

Registration Service Provider: DBMS VeriSign, dbms-support@verisign.com 800-579-2848 x4 Please contact DBMS VeriSign for domain updates,

DNS/Nameserver changes, and general domain support questions.

Registrar of Record: TUCOWS, INC. Record last updated on 27-Aug-2006. Record expires on 03-May-2014. Record created on 02-May-1991.

Domain servers in listed order: NS3.MSFT.NET 213.199.144.151 NS1.MSFT.NET 207.68.160.190 NS4.MSFT.NET 207.46.66.126 NS2.MSFT.NET 65.54.240.126 NS5.MSFT.NET 65.55.238.126

Hacking NetworksPhase 2: ScanningWar Driving: Can I find a wireless network?

War Dialing: Can I find a modem to connect to?

Network Mapping: What IP addresses exist, and what ports are open on them?

Vulnerability-Scanning Tools: What versions of software are implemented on devices?

Passive Attacks

Eavesdropping: Listen to packets from other parties = Sniffing

Traffic Analysis: Learn about network from observing traffic patterns

Footprinting: Test to determine software installed on system = Network Mapping

B

Packet A

C

Bob

JennieCarl

Hacking Networks:Phase 3: Gaining Access

Network Attacks: Sniffing

(Eavesdropping) IP Address Spoofing Session Hijacking

System Attacks: Buffer Overflow Password Cracking SQL Injection Web Protocol Abuse Denial of Service Trap Door Virus, Worm, Trojan

horse,

Login: Ginger Password: Snap

Some Active Attacks

Denial of Service: Message did not make it; or service could not run

Masquerading or Spoofing: The actual sender is not the claimed sender

Message Modification: The message was modified in transmission

Packet Replay: A past packet is transmitted again in order to gain access or otherwise cause damage

Denial of Service Joe

Ann

Bill SpoofingJoe (Actually Bill)

Ann

Bill

MessageModification Joe

Ann

Packet Replay Joe

Ann

Bill

Bill

Man-in-the-Middle Attack

10.1.1.1

10.1.1.2

10.1.1.3(1) Login

(3) Password

(2) Login

(4) Password

SQL Injection Java Original: “SELECT * FROM

users_table WHERE username=” + “’” + username + “’” + “ AND password = “ + “’” + password + “’”;

Inserted Password: Aa’ OR ‘’=’ Java Result: “SELECT * FROM

users_table WHERE username=’anyname’ AND password = ‘Aa’ OR ‘ ‘ = ‘ ‘;

Inserted Password: foo’;DELETE FROM users_table WHERE username LIKE ‘%

Java Result: “SELECT * FROM users_table WHERE username=’anyname’ AND password = ‘foo’; DELETE FROM users_table WHERE username LIKE ‘%’

Inserted entry: ‘|shell(“cmd /c echo “ & char(124) & “format c:”)|’

Login:

Password:

Welcome to My System

NIST SP 800-118 Draft

Password Cracking:Dictionary Attack & Brute Force

Pattern Calculation

Result Time to Guess(2.6x1018/month)

Personal Info: interests, relatives 20 Manual 5 minutes

Social Engineering 1 Manual 2 minutes

American Dictionary 80,000 < 1 second

4 chars: lower case alpha 264 5x105

8 chars: lower case alpha 268 2x1011

8 chars: alpha 528 5x1013

8 chars: alphanumeric 628 2x1014 3.4 min.

8 chars alphanumeric +10 728 7x1014 12 min.

8 chars: all keyboard 958 7x1015 2 hours

12 chars: alphanumeric 6212 3x1021 96 years

12 chars: alphanumeric + 10 7212 2x1022 500 years

12 chars: all keyboard 9512 5x1023

16 chars: alphanumeric 6216 5x1028

Hacking Networks:Phase 4: Exploit/Maintain Access

Backdoor

Trojan Horse

Spyware/AdwareBots

User-Level Rootkit

Kernel-Level Rootkit

Replaces systemexecutables: e.g. Login, ls, du

Replaces OS kernel:e.g. process or filecontrol to hide

Control system:system commands,log keystrokes, pswd

Useful utility actuallycreates a backdoor.

Slave forwards/performscommands; spreads,list email addrs, DOSattacks

Spyware: Collect info:keystroke logger,collect credit card #s,AdWare: insert ads,filter search results

Botnets

AttackerHandler

Bots: Host illegal movies, music, pornography, criminal web sites, … Forward Spam for financial gain

China Hungary

Botnets: Bots

Zombies

Distributed Denial of Service Zombies

VictimAttacker Handler

Can barrage a victimserver with requests,causing the networkto fail to respond to anyone

Russia Bulgaria UnitedStates

Zombies

Question

An attack where multiple computers send connection packets to a server simultaneously to slow the firewall is known as:

1. Spoofing

2. DDOS

3. Worm

4. Rootkit

Question

A man in the middle attack is implementing which additional type of attack:

1. Spoofing2. DoS3. Phishing4. Pharming

Network Security

Network Defense

Encryption

Security: Defense in Depth

Border RouterPerimeter firewallInternal firewallIntrusion Detection SystemPolicies & Procedures & AuditsAuthenticationAccess Controls

Bastion Host

Computer fortified against attackers

Applications turned off

Operating system patched

Security configuration tightened

Attacking the NetworkWhat ways do you see of getting in?

The Internet

De-MilitarizedZone

Private Network

Border Router/Firewall

Commercial Network

Private NetworkWLAN

Filters

Route Filter: Verifies sources and destination of IP addresses

Packet Filter: Scans headers of packets and discards if ruleset failed (e.g., Firewall or router)

Content Filter: Scans contents of packets and discards if ruleset failed (e.g., Intrusion Prevention System or firewall)

The good, the bad &the ugly…

Filter

The bad &the ugly

The Good

Packet Filter Firewall

Web Request

Ping Request

FTP request

Email Connect Request

Web Response

Telnet Request

Email Response

SSH Connect Request

DNS Request

Email Response

WebResponse

Illegal Source IP Address

Illegal Dest IP Address

Microsoft NetBIOS Name Service

FirewallConfigurations

A A

terminal

firewall

hostRouter Packet Filtering:Packet header is inspectedSingle packet attacks caughtVery little overhead in firewall: very quickHigh volume filter

A A

terminal

firewall

host

A

Stateful InspectionState retained in firewall memoryMost multi-packet attacks caughtMore fields in packet header inspectedLittle overhead in firewall: quick

FirewallConfigurations

A B

terminal

firewall

hostCircuit-Level Firewall:Packet session terminated and recreated via a Proxy ServerAll multi-packet attacks caughtPacket header completely inspectedHigh overhead in firewall: slow

A B

terminal

firewall

host

A

Application-Level FirewallPacket session terminated and recreated via a Proxy ServerPacket header completely inspectedMost or all of application inspectedHighest overhead: slow & low volume

A B

B

Router

External DNS

IDS Web Server

E-Commerce VPNServer

IDS

Protected Internal NetworkZone

IDSDatabase/File Servers

Internet

Multi-Homed Firewall:Separate Zones

Demilitarized ZoneWith ProxyInterface

ScreenedHost

The router serves as a screen for theFirewall, preventing Denial of Serviceattacks to the Firewall.

ScreeningDevice

Firewall

Writing Rules

Policies Network Filter Capabilities

Write Rules

Protected Network

Audit Failures

Corrections

Services and ServersWorkbook

Service Sensitivity Roles Server

Grades Confidential

For Graduates: TranscriptsFor Current Students: Advising, Students, Faculty

StudentScholastic

Billing Confidential,

For Current Students:Registration, Accounting, AdvisingPayment: Students

StudentBilling

Web Pages

Public Students, Employees, Public

Web services

Path of Logical AccessHow would access control be improved?

The Internet

De-MilitarizedZone

Private Network

Border Router/Firewall

Router/FirewallWLAN

Protecting the Network

The Internet

De-MilitarizedZone

Private Network

Border Router: Packet Filter

Bastion Hosts

Proxy server firewallWLAN

Serviced ApplicationsWorkbook

Applications

Sources of Entry

Servers Required Controls (e.g., Encryption)

Grades - Graduates

University Registration

Graduate Scholastic

Confidentiality, Integrity, Authentication

Grades – Current Students

United States

Student Scholastic

Confidentiality, Integrity, Authentication

Billing Payment: InternationalReports: Univ.

Student Scholastic

Confidentiality, Authentication, Integrity, Non-repudiation

Web Pages

International DMZ: PublicFace

Router

External DNS

Email PublicWeb Server

E-Commerce

Firewall

Zone 1:Student Labs & Files

Internet

Network DiagramWorkbook

Demilitarized Zone

Zone 2:Faculty Labs & Files

Student Records

Student Billing

Transcripts

StudentScholastic

StudentHistory

Zone 3:Student Data

StudentBilling

Intrusion Detection Systems (IDS) Intrusion Prevention Systems (IPS)

Network IDS=NIDS Examines packets for attacks Can find worms, viruses, org-

defined attacks Warns administrator of attack IPS=Packets are routed

through IPS

Host IDS=HIDS Examines actions or resources

for attacks Recognize unusual or

inappropriate behavior E.g., Detect modification or

deletion of special files

Router

Firewall

IDS

IDS Intelligence Systems

Signature-Based: Specific patterns are recognized

as attacks

Statistical-Based: The expected behavior of the

system is understood If variations occur, they may be

attacks (or maybe not)Neural Networks: Statistical-Based with self-learning

(or artificial intelligence) Recognizes patterns

Attacks:

NastyVirusBlastWorm

NastyVirus

NIDS:ALARM!!!

0

10

20

30

40

50

60

70

80

90

Mon. Tues. Wed. Thurs.

Sales

Personnel

Factory

Nor

mal

Honeypot & HoneynetHoneypot: A system with a special software application

which appears easy to break intoHoneynet: A network which appears easy to break into Purpose: Catch attackers All traffic going to honeypot/net is suspicious If successfully penetrated, can launch further attacks Must be carefully monitored

External DNS

IDS Web Server

E-Commerce VPNServer

Firewall

HoneyPot

Data Privacy

Confidentiality: Unauthorized parties cannot access information (->Secret Key Encryption

Authenticity: Ensuring that the actual sender is the claimed sender. (->Public Key Encryption)

Integrity: Ensuring that the message was not modified in transmission. (->Hashing)

Nonrepudiation: Ensuring that sender cannot deny sending a message at a later time. (->Digital Signature)

Confidentiality Joe

Ann

Bill AuthenticityJoe (Actually Bill)

Ann

Bill

Integrity Joe

Ann

Non-Repudiation Joe

Ann

Bill

Encryption – Secret KeyExamples: DES, AES

EncryptKsecret

DecryptKsecret

plaintextciphertext

plaintext

P = D(Ksecret, E(Ksecret,P))

NIST Recommended: 3DES w. CBC AES 128 Bit

Public Key EncryptionExamples: RSA, ECC, Quantum

EncryptKpublic

DecryptKprivate

Key ownerJoe

Encryption(e.g., RCS)

DecryptKpublic

EncryptKprivate

Message, private key

Digital Signature

Key owner

Authentication,Non-repudiation

Joe

P = D(kPRIV, E(kPUB,P))

P = D(kPUB, E(kPRIV,P))NIST Recommended: RSA 1024 bit2011: RSA 2048 bit

Remote Access Security

Virtual Private Network (VPN) often implemented with IPSec

Can authenticate and encrypt data through Internet (red line) Easy to use and inexpensive Difficult to troubleshoot, less reliable than dedicated lines Susceptible to malicious software and unauthorized actions Often router or firewall is the VPN endpoint

The Internet

Firewall

VPN Concentrator

Secure Hash FunctionsExamples: SHA1, SHA2, MD2, MD4, MD5

Message

H H E

Message HMessage H

D

H H

H

Compare

Message Authentication Code

Message

H

Message Message

H

H H H

H

Compare

One Way Hash

K K

K K

Ensures the message was not modified during transmission

NIST Recommended: SHA-1, SHA-22011: SHA-2

Encrypted K(Sender’s Private)

Digital Signature

Electronic Signature Uses public key

algorithm Verifies integrity of

data Verifies identity of

sender: non-repudiation

Message

Msg Digest

Public Key Infrastructure (PKI)

DigitalCertificate User: Sue

Public Key:2456

1. Sue registers withCA through RA

Certificate Authority(CA)

Register(Owner, Public Key) 2. Registration Authority(RA) verifies owners

3. Send approvedDigital Certificates

5. Tom requests Sue’s DC 6. CA sends Sue’s DC

Sue

Tom

4. Sue sendsTom messagesigned withDigital Signature

7. Tom confirmsSue’s DS

Network Access Server

NAS: Network Access Server Handles user authentication, access control and accounting Calls back to pre-stored number based on user ID Prone to hackers, DOS, misconfigured or insecure devices

RADIUS: Remote Access Dial-in User ServiceTACACS: Terminal Access Control Access

1. Dial up and authenticate

2. Call back

RADIUS orTACACS

3. Connect

Web Page Security

SQL Filtering: Filtering of web input for SQL Injection

Encryption/Authentication: Ensuring Confidentiality, Integrity, Authenticity, Non-repudiation

Web Protocol Protection: Protection of State

Vulnerability Assessment

Scan servers, work stations, and control devices for vulnerabilitiesOpen services, patching, configuration

weaknesses Testing controls for effectiveness

Adherence to policy & standards Penetration testing

Serviced ApplicationsWorkbook

Applications

Sources of Entry

Servers Required Controls (e.g., Encryption)

Grades – Current Students

United States

Student Scholastic

Confidentiality: EncryptionIntegrity: Hashing, IDSAuthentication: VPN/IPsec, secure passwords

Billing Payment: InternationalReports: Univ.

Student Scholastic

Confidentiality: Encryption, HTTPsAuthentication: VPN/IPsecIntegrity, Hashing, IDSNon-repudiation: Digital Signature

Summary of Network Controls

Network Security Techniques Encryption: Public and Private

key, Wireless WPA2 Virtual Private Network (VPN):

Secure communications tunnel Secure Hashing Digital Signature Bastion Host Configuration Certificate Authority: PKI

Network Protection Devices Firewall: Packet, Stateful,

Circuit, Application-Level Proxy server Demilitarized Zone (DMZ) Intrusion Detection System Intrusion Prevention System Network access server

(RADIUS or TACACS) Honeypot, honeynet

Secure Protocols SSL: Secure web SSH: Secure telnet/rlogin or

file transfer S/MIME: Secure email Secure Information Mgmt: Log

mgmt

Question

A map of the network that shows where service requests enter and are processed

1. Is called the Path of Physical Access

2. Is primarily used in developing security policies

3. Can be used to determine whether sufficient Defense in Depth is implemented

4. Helps to determine where antivirus software should be installed

Question

The filter with the most extensive filtering capability is the

1. Packet filter

2. Application-level firewall

3. Circuit-level firewall

4. State Inspection

Question

The technique which implements non-repudiation is:

1. Hash

2. Secret Key Encryption

3. Digital Signature

4. IDS

Question

Anti-virus software typically implements which type of defensive software:

1. Neural Network

2. Statistical-based

3. Signature-based

4. Packet filter

Question

MD5 is an example of what type of software:

1. Public Key Encryption

2. Secret Key Encryption

3. Message Authentication

4. PKI

Question

A personal firewall implemented as part of the OS or antivirus software qualifies as a:

1. Dual-homed firewall2. Packet filter3. Screened host4. Bastion host

HEALTH FIRST CASE STUDY

Designing Network Security

Jamie Ramon MDDoctor

Chris Ramon RDDietician

TerryLicensed Practicing Nurse

PatSoftware Consultant

Define Services & Servers

Which data can be grouped together by role and sensitivity/criticality?

Service Name

Sensitivity Class.

Roles with Access

Server Name

              

Confidential –Management

Public – Web Pages

Privileged –Contracts

Defining Services which can Enter and Leave the Network

Service Source

(e.g., home, world, local computer)

Destination

(local server, home, world,

etc.)

          

Defining Zones and Controls

Compartmentalization:Zone = Region (E.g., DMZ, wireless, internet)Servers can be physical or virtual

Zone Service

 

Server Required Controls

(Conf., Integrity, Auth., Nonrepud., with tools: e.g., Encryption/VPN)

              

Router

External DNS

Email PublicWeb Server

E-Commerce

Firewall

Zone 1:Student Labs & Files

Internet

Draw the Network Diagram

Demilitarized Zone

Zone 2:Faculty Labs & Files

Student Records

Student Billing

Transcripts

StudentScholastic

StudentHistory

Zone 3:Student Data

StudentBilling

ReferenceSlide # Slide Title Source of Information

7 Passive Attacks CISA: page 331,333, 352

9 Some Active Attacks CISA: page 330, 332, 352

10 Man-in-the –Middle Attack CISA: page 331

12 Password Cracking: dictionary Attack & Brute Force CISA: page 330

14 Botnets CISA: page 330

15 Distributed Denial of Service CISA: page 330

23 Packet Filter Firewall CISA: page 353, 354

24 Firewall Configurations CISA: page 353 – 355

25 Firewall Configurations CISA: page 354

26 Multi-Homed Firewall: Separate Zones CISA: page 355

33 Intrusion Detection Systems (IDS)Intrusion Prevention System (IPS)

CISA: page 355, 356

34 IDS Intelligence Systems CISA: page 356

35 Honeypot & Honeynet CISA: page 356, 357

37 Encryption – Secret Key CISA: page 357

38 Public Key Encryption CISA: page 357, 358

39 Remote Access Security CISA: page 361

40 Secure Hash Functions CISA: page 359, 361, 362

41 Digital Signature CISA: page 359

42 Public Key Infrastructure (PKI) CISA: page 359, 360