Robert H Deng, SIS-SMU, 20051 Lecture 5 E-Banking.

Robert H Deng, SIS-SMU, 2005 1

Lecture 5

E-Banking


Outline

• Definition of e-banking• Entity authentication and secure communications• Server side architecture & security• Web client security • Web application security


What Is E-Banking

• Definition– The automated delivery of new and traditional

banking products and services directly to customers through electronic, interactive communication channels.

• Products and Services– Account information and management– Bill presentation and bill payment– Loan applications and approval– Investment and brokerage services– …


Stages of E-Banking

• Automatic Teller Machine (ATM): – An economical substitute for brick and mortar branches, longer

banking hours– Services: Balance enquiry; cash withdrawal, deposit, funds

transfer, payment for IPO offerings, COE bidding, etc

• Tele-Banking:– Retail banking by dial a phone #, automatic voice response– all services as ATM except cash withdrawal and deposit

• PC-Banking – Dial into a bank’s intranet proprietary software system to access

accounts for transactions


Stages of E-Banking: Internet-Banking

• Definition:– Consumers access banking products and services over the Internet

• Advantages– PC-banking were proprietary, developed just by the bank– Internet puts everyone on an equal footing. There is a wealth of 3rd party

providers– The cost per transaction through the Internet is 27 times less than

through ATMs, 54 times less than that of a telephone transaction and 107 times less than that of a physical branch transaction.

• The Risks– There is security risk in using any remote-access for financial services,

internet banking poses the greatest risk since internet is an open and public network.


Internet Banking - Informational Websites

• Objective– Bank wants to provide

information to the public and its customers

– Bank wants to verify the information is correction and the web site is usually up

• Risk issues– Potential liability for inaccurate

information – Potential liability for spreading

viruses and other malicious code to computers accessing the website

– Negative public perception if the bank’s online service is disrupted or website defaced or presents offensive material

Inside ABC BankCompany InformationInvestor RelationsNews RoomCareersABC Bank in the CommunityDoing Business with ABC Bank

Help CenterContact UsATM/Branch locationsSelf ServicesFrequently Asked Questions


Internet Banking – Transactional Websites

• Objective– Provide banking services in a secure

and reliable manner• Risk Issues

– Higher risk than info website due to exchange of confidential customer info and transfer of funds

– Authentication processes– Liability for unauthorized transactions– Losses from fraud if the bank fails to

verify user identity– Violations of laws or regulations

pertaining to consumer privacy, anti-money laundering, anti-terrorism etc

– Negative public perception, customer dissatisfaction, liability resulting from failure to process 3rd-party payments as directed or within a time frame.

Inside ABC BankCompany InformationInvestor RelationsNews RoomCareersABC Bank in the CommunityDoing Business with ABC Bank

Help CenterContact UsATM/Branch locationsSelf ServicesFrequently Asked Questions

Access Accounts

Personal Account LoginCommercial Account Login


Consumer Switch Banks Due to Identity Theft

• close to 60% expressed concern about identity theft• 6% switched banks to reduce their risk of becoming a victim of identity theft


Outline



Working with a Simplified Model

User InternetWebsitein DMZ

Bank’sNetwork

AuthServer

Database

• Security requirements– User authentication, confidentiality and integrity– How about non-repudiation?

• Possible means of user authentication:– Using user’s public key certificate– Using smart card and possibly in combination with biometric– Most e-banking systems use PIN (or password); backward

compatible with legacy systems


Using SSL for Internet Banking

UserWebsitein DMZ

Bank’sNetwork

AuthServer

Database

• Secure communication over internal network– Communication between web server and bank’s internal servers are protected using

IPSEC (Internet Protocol Security)

• Secure communication over the Internet– Bank obtains public key certificate from a CA– Bank’s private key kept at web server, ideally in a tamper-resistant hardware– User and web server runs SSL, authenticate server and set up a secure tunnel

• Customer authentication– Customer sends PIN in clear text over the secure tunnel

Internet


Using WTLS for Wireless Banking

UserPub or Priv

NetworkWebsitein DMZ

Bank’sNetwork

• Secure communication from WAP gateway to bank internal servers– Communication between web server and bank’s internal servers using IPSEC;

communication between WAP Gateway and web server using SSL

• Secure communication over the Internet– Bank obtains an ephemeral public key certificate for the WAP Gateway from a

CA (valid for 25 hours)– User and web server runs WTLS (Wireless Transport Layer Security),

authenticate gateway and set up a secure tunnel

• Customer authentication– Customer sends PIN in clear text over the tunnel

WirelessNetwork

WAPGateway


The Security “Gaps”

• “Web server gap”: In “SSL for Internet Banking”, cleartext appears in the web server, which may be in house or hosted by a service provider; web server is vulnerable to attacks

• “WAP gaps”: In “WTLS for Wireless Banking”, cleartext appears in WAP gateway (which is normally hosted by a cellular operator) and in the web server

• Directive from a central bank: “all PINs must be protected end-to-end, from customer terminal to bank’s authentication server”.


Outline



Server Side Architecture & Security - Demilitarized Zone (DMZ)

• DMZ– A semi-trusted network zone to segment off systems that

accessed by Internet users from those that are accessed by internal users and servers

• DMZ policy rules– Any system that can be directly contacted by an external user

(web server, external mail server, external DNS server, etc) should be placed in DMZ.

– DMZ systems are always under attack and can not be trusted, should be severely restricted from accessing internal systems. Ideally, internal system should initiate connection to DMZ systems.


Server Side Architecture & Security - A typical DMZ architecture

InternalNetwork

InternetFirewall

Web Server

ExternalMail Server

ExternalDNS Server

Only services offeredby DMZ systems

Responseonly

Initiateconnections

DMZ


A Typical E-Banking Server Side Architecture

Bank InternalNetwork

Internet

Firewall1

E-bankingApp Server

WebServer

DatabaseServer

HSM

HSM – Hardware Security Module

F/W only allows accessports 80 and 443 on the web server

Firewall2

Firewall3Makes SQL queries to

database server


E-Banking Server Side Architecture- Web Server, App Server, Database Server

• Web Server– Sensitive information: Open to access from the Internet; is at most semi-

trusted. Should not store sensitive information; PINs only transit through it, should not be kept on it

– Server location: Firewall1 only allow access to ports 80 and 443 on web server

– OS configuration: Remove all unnecessary services; Check for and load latest patches

– Dual home web server, one interface for web traffic and responds to customer; another (may resides on a 2nd DMZ) handle application queries to the e-banking server

• E-Banking Server– process customer requests, makes SQL queries to the database server

and provides information to the Web server for presentation to customers

• Database Server– contains lots of sensitive information, is located in the internal network,

no Internet connection


E-Banking Server Side Architecture- Communication with Database Server

• Ideal solution– e-banking app server does not make connection to database

server, but the latter initiate connection to the former; – however this delays response and is not acceptable

• Practical solution– e-banking app server uses an ID and secret key to access the

database, but the secret key may be compromised. – make the ID very restrictive, e.g., read access to non-sensitive

information– couple e-banking app server ID & secret key with customer

authentication information to access the customer sensitive information


A High Availability E-Banking Server Side Architecture

App layer switches provideload sharing & fail-over across

web servers

Routers & firewalls arecross-connected to switchesto provide redundant paths

App layer switch Firewall Switch Router

Internet

ISP #1 POP

ISP #2 POP

BGPrunningbetween

ISPs

Web servers

e-banking app servers

Internalnetwork

Database serveron redundant cluster


Outline



Web Spoofing

Victim’sbrowser Attacker

Web Server

1. Requestspoofed URL

2. Requestoriginal URL

3. Original pagecontents

4. Change page

5. Spoofed pagecontents


Web Spoofing

• Attacker 1. makes victim visit his web page (e.g., by phishing attack)2. either sends victim a fake page or passes on the original URL request

to the real web server (e. g., function as a proxy)3. intercepts response4. may change the response5. sends the response to victim

• Consequences– Attacker may get victim’s account and password, may spoof stock

market information

• Difficult to counter– Victim may not be able to recognize it’s fake. Browser’s location line

and status may be changed by attacker using JavaScript– Victim needs to examine SSL certificate’s owner carefully!


Phishing Attack

• One of the most prolific identity theft attacks, especially targeting e-banking users

• Some recent statistics (figures for Oct 2004, based on Comodo Inc unless otherwise stated):– Some 57 Million US Internet users have identified the

receipt of an e-mail linked to a Phishing scam --- Gartner 2004

– Number of active Phishing sites: 1142– Average monthly growth rate July-Oct 2004: 25%– Country hosting the most Phishing websites: USA

Average time online for a site: 6.3 days– Longest time online for a site: 31 days


Mounting Phishing Attacks

• Attacker directs victim to a malicious website typically via e-mail spoofing

• E-mail spoofing: E-mail seems to origin from a trusted company and urges users to follow a hyperlink referring to a malicious server having a web domain name similar to that of the spoofed site. Examples:– http://www.signin.abcbanker.com, easily confused

with http://www.signin.abcbank.com. – http://[email protected], refers to

the.attacker.com instead of www.paypal.com which is interpreted as a login name instead of an address


Phishing Attack to DBS Singapore's DBS warns of fraudulent site in Hong Kong

Posted: 11:02 PM (Manila Time) | Dec. 27, 2003Agence France-Presse

SINGAPORE -- The Hong Kong Monetary Authority and police are working to shut a fraudulent online banking website claiming to be a part of Southeast Asia's largest lender DBS Bank, the Singapore-based bank said.

"DBS Bank wishes to advise that this website has no affiliation whatsoever with DBS Bank, nor the Group," the company said in a statement on its website. "DBS Bank has reported the fraudulent website to the Hong Kong Monetary Authority and the police, who are working with relevant authorities to shut down the fraudulent website."

The fraudulent website, www.dbshk.net, has two small boxes for customers to fill in their account names and passwords to access a list of online banking services.

It features the bank's distinctive red logo and even a picture of the smiling female bank teller clad in the grey uniform that greet online customers on the actual Internet site.


Outline



Web Application Security

• More and more web based applications; they are becoming one of the major targets for attacks– 70% of new attacks target the web (SQL injection,

buffer overflow, etc)

• Network based firewalls and IDS are entirely blind to encrypted web traffic

• Firewalls let in web traffic through ports 80 and 443


Web Application Security Gateway

Flash Demo: http://www.teros.com/products/appliances/gateway/attacks_defeated.shtml


Summary

• Definition of e-banking• Entity authentication and secure

communications (the “gap” problem)• Server side architecture & security (DMZ policy

rules)• Web client security

• Web application security and application security gateway


• Reading assignments:

– http://www.ffiec.gov/ffiecinfobase/html_pages/ebanking_book_frame.htm

Robert H Deng, SIS-SMU, 20051 Lecture 5 E-Banking.

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Transcript of Robert H Deng, SIS-SMU, 20051 Lecture 5 E-Banking.