Download Securing a Large Application

Securing Large Applications
CSCI 5931 Web Security
Rungang Mo,
Yingying Sun
Revised by A. Yang
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.
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:
Register
Entry
Balance
Connections
– Customer to web
server:
• Most dangerous;
• Using SSL with
mutual
authentication
Network topology
Bank
Customer
– Web server to
middleware:
• RMI over SSL
– Middleware to
database:
• RMI over SSL
– Credit card viewer to
middleware:
• Using SSL with
authentication
Web Server
Middleware
Credit
Card
Viewer
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
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;
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
Generate the keys
– Using default Java keystore to handle trust
and authentication;
– Create private and public keys for each
component;
– 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)
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
certificates
• Trusted certificates in Internet Explorer
The Database
– MySQL:
• Cross-platform and freely available for noncommercial use;
– Tables:
• Accounts: ID, name, balance, certificate
serial number.
• Credit_card: account_id, session_key,
cc_number.
– The database driver:
• secureDriver_config.xml – config. Info for the
secure driver
• secureDriver.policy – grant permissions to
connect, etc.
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.
The Bank Interface
– Four methods contained in the Bank class:
• register(): register a new account given basic
user 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
the account Ids in the database.
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,
certificate serial number;
– CreditCardDBO class:
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
object in the database separately;
• Use the BASE64 encoder and decoder classes;
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 ();
Starting the Bank
– The BankInit class:
• Construct a BankImpl object with a Properties
object that we read off the file system;
• Commond-line argument indicates the
properties file to read;
• Call Naming.rebind () on it so that it becomes
available for RMI client;
• A bug in JSSE v.1.0.2 and earlier.
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:
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;
Servlets and JSPs Diagram
index.html
BalanceServlet
invalidLogin.html
register.html
RegisterServlet
alreadyRegistered.html
balance.jsp
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:
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
BankApp;
– Enable SSL;
– Enable policy support;
– Add support file
– Edit web server startup scripts
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.
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
keystore password on the command line;
• Adding support for RMI: CreditCardClient class:
– decryptCreditCardDBO();
– main();
– getPassword();
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:
Possible Modifications
– Logging:
– Using SSL:
– Web browser authentication:
– The database:
– Encrypting SSL keys:
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