Wireless Security By Sandeep Kumar Sharma

An Introduction of

Wireless & mobile Security Submitted by: Sandeep Sharma M.TECH(NM) DAVV(SCSIT)

Overview  Security

Basics  Wireless Security  WTLS & SSL  WAP Security Models  WIM, WMLScript, Access Control  Summary  References

Security Primer Security Goals -Authentication -Confidentiality - Data Integrity -Authorization -Non-Repudiation

Different Views Privacy 

Assure privacy of information (i.e., no one other than the authorized people can see the information) in storage or transmission

Integrity The integrity of information (i.e., no unauthorized modification) Authentication: Identify for certain who is communicating with you Authorization (Access control): Determine what access rights that person has.

Accountability (Auditing): . assure that you can tell who did what when and convince yourself that the system keeps its security promises. Includes non-repudiation (NR) -- the ability to provide proof of the origin or delivery of data. NR protects the sender against a false denial by the recipient that the data has been received. Also protects the recipient against false denial by the sender that the data has been sent. a receiver cannot say that he/she never received the data or the sender cannot say that he/she never sent any data Availability: access to system when a user needs it

WTLS

WAP System Architecture

WML WMLScript WTAI Etc.

Web Server

WAP Gateway WML Encoder

WSP/WTP

WMLScript Compiler Protocol Adapters

HTTP

CGI Scripts etc.

Content

WML Decks with WML-Script

Client

Security in WAP WAP can secure

GSM Security

communication between terminal and WAP gateway.

Wireless Network

Terminal

FIREWALL

FIREWALL

Leased modem pool

For communications between gateway and origin server, other means e.g. SSL are required. Internet

WAP S ecurit y

WAPCompan Gateway y intranet

Origin Server Internet Security

Wireless security Issues

 Several

security concerns at all layers

 Wireless

networks (cellular, wi-fi, adhoc,

satellite)  Wireless platforms (Mobile IP, WAP, IMode, Wireless Java, Mobile Web services)  Mobile applications (holding digital certificates in handsets)  Too

many issues needing attention

 Cellular

security (location services)  Satellite security (GAO report)  Mobile adhoc network security  Wireless platform security (WAP, BREW)  M-application security (handset certificates)  An

architecture approach is needed – a solution that considers tradeoffs and

Sample Wireless Security Technologies Applications

Can use higher level services to compensate for lower layers Tradeoffs in performance and security

Middleware

TCP/IP

Wireless Link

•SET for transaction security •S/MIME and PGP for secure email •Java security (sandboxes) •Database security

•SSL and TLS •WAP security (WTLS) •Web security (HTTPS, PICS, HTTP Headers) •Proxy server security

•IPSEC and wireless VPN •Mobile IP

•802.11 security (WEP) •Cellular network security •Satellite link security •WLL and cordless link security

Security Tradeoffs Telnet FTP SMTP HTTP TCP /IP a) Physical Network Level Security (encryption at physical network level) Physical Network (layer1 –2)

Telnet FTP SMTP HTTP

b) Transport Level Security (encryption at IP level)

IPsec (VPN) Physical network PGP S/MIME

c) Higher Level Security (encryption at SSL or application level) Legend: light areas indicate security (say encryption)

A3

A3

A2 A1

HTTP

SMTP SSL TCP /IP Physical network

Table 12-1 Security Considerations – Mapping Technology to Needs Technologies

Privacy

Integrity

Encryption

X

X

Password protection

X

X

Digital signatures

X

Message Digest

X

Digital certificates ACL Audit trails Redundancy

X

X

Authentication and Authorization

Accountability Availability and (NonDenial of service repudiation)

X

X X X X

Table 12-2 Security Levels Security Level

Example of Security

Why Needed?

Why Not Enough?

Application-level security

SET, PGP, S-MIME

Provide security specific to and application

Only protection of application-specific data

Client/Server Security

SSL and WTLS Security

Assures secure communication over an unsecured link

Only middleware-level security

IP Level

IPSec, VPN

Protects the IP path

Does not protect databases

Network Link Level

Wireless LAN Security, 3G and Satellites Security

Deters breaking in at physical link level

Protects only one link. Does not cover other links in a large network

WAP Security

WAP Phone

Wireless network with uses WTLS Security

WAP Gateway WML Browser WML Script

•Protocol Adapters •WML Encoder •WMLScript Compiler

Internet uses SSL Security

Web Server • CGI Scripts

Content

Digital authentication process.

Security Technologies  Cryptography Symmetric:

3DES, RC4, etc. Asymmetric: RSA, Diffie-Hellman  Key

Exchange( RSA, DiffieHellman)  Digital Signatures (RSA,DSS)  Digital Certificates(x.509.wtls)  PKI

Wireless Security  Link

Layer Security

GSM

CDMA

 Application WAP:

Layer Security

WTLS, WML, WMLScript, & SSL I Mode: N/A SMS: N/A

Sample Of Digital Certificate Digital Certificate Subject name : Sandeep Public key

:

Serial Number Other data

:

<san_cse22> :

10291021 Email

[email protected] Valid from : 8 july 2008 Valid to

: 8 july 2010

Issuer Name : DAVV (scsit)

Digital Certificate creation steps Key Generation

Registration

Verification

Certificate Creation

Some digital signature algorithms

    

RSA DSA ECDSA ElGamal signature scheme Undeniable signature SHA (typically SHA-1) with RSA

Types of Digital Certificates  E-Mail

Certificates  Browser Certificates  Server (SSL) Certificates  Software Signing Certificates

CERTIFICATE AUTHORITY

KUa

CA =E k R auth[time1,iDa,ku a]

KUb 5

1

CB = E k R auth[time1,IDb,ku b]

2

3

CA

6

CB

4

Sample X.509 certificates v1         



Certificate:

Data: Version: 1 (0x0) Serial Number: 7829 (0x1e95) Signature Algorithm: md5WithRSAEncryption Issuer: C=ZA, ST=Western Cape, L=Cape Town, O=Thawte Consulting cc, OU=Certification Services Division, CN=Thawte Server CA/[email protected] Validity Not Before: Jul 9 16:04:02 2008 GMT Not After : Jul 9 16:04:02 2010 GMT Subject: C=India, ST=M.P., D=indore, O=D.A.V .V., OU=FreeSoft, CN=www.freesoft.org/[email protected] Subject Public Key Info: Public Key Algorithm: rsaEncryption RSA Public Key: (1024 bit) Modulus (1024 bit): 00:b4:31:98:0a:c4:bc:62:c1:88:aa:dc:b0:c8:bb: 33:35:19:d5:0c:64:b9:3d:41:b2:96:fc:f3:31:e1: 66:36:d0:8e:56:12:44:ba:75:eb:e8:1c:9c:5b:66: 70:33:52:14:c9:ec:4f:91:51:70:39:de:53:85:17: Exponent: 65537 (0x10001) Signature Algorithm: md5WithRSAEncryption 93:5f:8f:5f:c5:af:bf:0a:ab:a5:6d:fb:24:5f:b6:59:5d:9d: 92:2e:4a:1b:8b:ac:7d:99:17:5d:cd:19:f6:ad:ef:63:2f:92: ab:2f:4b:cf:0a:13:90:ee:2c:0e:43:03:be:f6:ea:8e:9c:67: d0:a2:40:03:f7:ef:6a:15:09:79:a9:46:ed:b7:16:1b:41:72: 0d:19:aa:ad:dd:9a:df:ab:97:50:65:f5:5e:85:a6:ef:19:d1

Process of x.509 certificate obtaining

Steps of Communication

How does a stream cipher work? Keystream Generator

IV+Key

IV+Key

Keystream

Keystream Plaintext

Keystream Generator

Ciphertext Encrypt

IV: Initialization vector

Plaintext Decrypt

Encryption with WEP Plaintext

Message

CRC

XOR Keystream = RC4(v, k)

IV

Ciphertext Transmitted data

Encryption with WEP  RC4

used with 40-bit key  „128-bit“ implementation  Per-packet 24-bit IV  WEP allows re-use of IV  32-bit CRC is a linear function of the message and does not depend on the key

No non- repudiation 3 Sorry, I can not decide this!

2

I did not receive any me by Alice. The log file has been fak by Alice!

1 I have canceled the contract for my flat 3 months ago. WTLS Logfile

Reason: The record protocol is based on symmetric cryptography

Wireless IDS HYPE: External wIDS sensors are the best way to detect and remediate all wireless attacks REALITY: Most attacks/events occur on the AP/Client channel ROGUES and AD HOCs: Detected quickly via intelligent off channel scanning

On-channel attack detected 802.11a Channel 153 Off channel rogue detected Rogue AP AP contains rogue client Off channel ad hoc net detected AP contains ad 802.11g Channel 1 hoc net Ad Hoc client ent m n i ntaContainment o C RF RF

802.11a Channel 153 Rogue client

802.11g Channel 6 Valid client

802.11g Channel 1 Ad Hoc client

802.11g Channel 6 Attacker

802.11a Channel 152 Valid client

THANKS FOR LISTENING ANY DOUBT ?