Transcript
Page 1: Securing Large Applications

Securing Large Applications

CSCI 5931 Web Security

Rungang Mo,

Yingying Sun

Revised by A. Yang

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Content

– Designing an online banking application;– Setting up the keys and certificates;– Configuring the database;– Building a database access tier;– Developing a web tier;– Constructing a client application;– Looking at areas for improvements.

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Online banking– Main features:

• Accept credit cards to open accounts;• Allow users to view their own account;• Allow finance agent to view all credit card data.

– Web Interface:

Entry

Register

Balance

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Network topology

BankCustomer

Web Server

Middleware CreditCard

Viewer

– Customer to web server:

• Most dangerous;• Using SSL with

mutual authentication

– Web server to middleware:

• RMI over SSL

– Middleware to database:

• RMI over SSL

– Credit card viewer to middleware:

• Using SSL with authentication

Connections

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Application security

– Database:• Encrypt credit card numbers by public key;• Run secure JDBC driver on the database.

– Middleware (Bank):• Only allow connections from web server and

credit card client.

– Credit card client:• Decrypt and view credit cards

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Application security (cont.)

– Web server:• Block access to most ports with a firewall.

– Web browser:• Using client authentication;• The browser protects the private key with

password-based encryption;

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Setting up the keys -Relationship between Components

Component Trusted Component(s)

Web Browser Web Server

Web Server (Tomcat) Web Browser, Middleware

Middleware (Bank component)

Web Server, Credit Card Client, Database

Credit Card Client Middleware

Database (MySQL) Middleware

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Generate the keys– Using default Java keystore to handle trust

and authentication;– Create private and public keys for each co

mponent;– Create truststore for each component that

contain the appropriate public keys;– Get a key from Thawte for web browser;– Using keytool to create the rest of the keys

and certificates for credit card client, middleware, and database. (Page 366)

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Export/ Import the certificates

– In order to establish trust, we need to export all the certificates that need to be trusted:

• c:\> keytool -export -keystore bankKeyStore -file bank.cer

– Set up trust by creating trust store:• Web Server: need to trust a number of certificat

es• Trusted certificates in Internet Explorer

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The Database– MySQL:

• Cross-platform and freely available for non- commercial use;

– Tables:• Accounts: ID, name, balance, certificate seria

l number.• Credit_card: account_id, session_key, cc_nu

mber.

– The database driver:• secureDriver_config.xml – config. Info for the

secure driver• secureDriver.policy – grant permissions to co

nnect, etc.

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The Middleware - The Bank

– Creating an interface for clients to use;– Building data objects to enable items to be

stored in the database;– Creating an RMI object to connect the

interface to the data objects;– Constructing a way of starting the

middleware;– Configuring the middleware.

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The Bank Interface

– Four methods contained in the Bank class:• register(): register a new account given basic u

ser information.• getAccount(): find the account for a given client

certificate serial number.• getCreditCardDBO(): fetch the encrypted credit

card information for a given account ID.• getAllCreditCardAccountIDs(): get a list of all th

e account Ids in the database.

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Data objects

– Account class: • Hold information, which is not encrypted;• Contains accountID, balance, customer name,

certificate serial number;

– RegistrationInformation class: • Wrap up all of the user-entered information;• Contains credit card number, balance, name, c

ertificate serial number;

– CreditCardDBO class:

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Data objects (cont.)

– DatabaseOperations class:• Class for performing database operations;• Use the JDBC proxy to encrypt the connection

using RMI over SSL;• Store CreditCardDBO object and Account objec

t in the database separately;• Use the BASE64 encoder and decoder classes;

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Bank Implementation

– Creating an RMI object: BankImpl to connect the interface to the data objects;

– Extend UnicastRemoteObject so that it can be used over RMI;

– Important methods:• BankImpl ();• register ();• getAccount ();• getAllCreditCardAccountIDs ();• getCreditCardDBO ();

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Starting the Bank

– The BankInit class:• Construct a BankImpl object with a Properties o

bject that we read off the file system;• Commond-line argument indicates the propertie

s file to read;• Call Naming.rebind () on it so that it becomes a

vailable for RMI client;• A bug in JSSE v.1.0.2 and earlier.

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Configuration

– config.properties: define JDBC configuration and the location of the public key;

– BankInit.policy: start up the bank;– Collecting the files:

• SecureDriverClient.jar;• Bank.jar;• Associated data: keystore/ truststore/ creditcard.

cer

– Running the Bank:

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The Web Server

– Main functions:• Registration;• Account viewing.

– Using SSL client authentication to identify users;

– Build the servlets and JSPs for the web tier;

– Look at packaging the web application and deploying to Tomcat;

– Run the application;

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Servlets and JSPs Diagram

index.html

invalidLogin.html

register.html

alreadyRegistered.html

RegisterServlet

BalanceServlet balance.jsp

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Servlets and JSPs– HTMLs:

• Register: sends data to RegisterServlet;• Login: takes users to the BalanceServlet;

– Servlets:• RegisterServlet: handles creating account;• BalanceServlet: loads account information, and sends it to a

JSP for display• AbstractEcommerceServlet:

– init();– getCertificate();– getRedirectURL();

– balance.jsp:

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Packaging the web application

– Policy file for Tomcat: tomcat.policy – Modifying web.xml;– Build the WAR file;– Copy the WAR file into Tomcat;– Delete other Webapps and Add the BankA

pp;– Enable SSL;– Enable policy support;– Add support file– Edit web server startup scripts

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Start the application

– Start the RMI registry on the database server;

– Start the database driver;– Start the RMI registry on the bank;– Start the bank;– Start the web server.

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Credit Card Client

– Allows a user to view all of the credit cards in the database, decrypting them with the private key;

– Modifications on Chapter 10 example:• The GUI for password instead of setting the key

store password on the command line;• Adding support for RMI: CreditCardClient class:

– decryptCreditCardDBO();– main();– getPassword();

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Credit Card Client (Cont.)

– Credit card client policy file: CreditCardClient.policy (Page 409);

– Packaging the credit card client: • create a JAR file, CreditCardClient.jar;• create a directory for the credit card client;

– Running the credit card client:

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Possible Modifications

– Logging:– Using SSL:– Web browser authentication:– The database:– Encrypting SSL keys:

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Reference

– Jess Garms, Daniel Somerfield-- Professional Java Security;

– http://www.wrox.com;– http://xml.apache.org/xerces-j/index.html;– http://jakarta.apache.org/tomcat/index.html;– http://www.mysql.com– http://www.thawte.com/certs/personal– http://www.bouncycastle.org