Designing Security In Web Applications Andrew Tomkowiak 10/8/2013 UW-Platteville Software Engineering Department

Web Applications I will talk about ways to design a web application to be more secure and some basic guidelines to follow when developing web applications.

Web Applications Authenticate Users http applications are stateless Design secure session management mechanisms

Vulnerabilities Web Applications  Input Validation  Authentication  Authorization  Configuration Management  Sensitive Data  Session Management  Cryptography  Parameter Manipulation  Exception Management  Auditing and Logging

Web Applications These systems need to have a significant amount of time spent on them in the design phase. Why?

Web Application  Assume all input is malicious  Centralize your approach  Do not rely on client-side validation  Be careful with canonicalization issues  Constrain, Reject and sanitize your input Input

Web Application Validate data for type, length, format and range. Sanitize- Strip excess null characters or spaces etc...

Authentication Web Applications  User names and passwords sent over secure channel(SSL)  Credentials stored  Credentials verified  Authentication ticket to verify user after logon(cookie)  Separate public and restricted areas.  Use account lockout policies for end-user accounts.  Support password expiration periods.  Be able to disable accounts.  Do not store passwords in user stores.  Require strong passwords.  Do not send passwords over the wire in plaintext.  Protect authentication cookies

Authorization Web Applications  Use multiple gate keepers  Restrict user access to system level resources  Consider authorization granularity  Hybrid model

Configuration Management Web Applications  Secure Administration interfaces  Secure your configuration stores  Maintain separate administration privileges  Use least privileged process and service accounts

Web Application  Storing secrets  Do not store any keys or passwords in plain text  Retrieve data on demand  Secure the communication between client and server  Do not store data in cookies Sensitive Data

Web Application  Use SSL to protect session cookies  Encrypt the contents of the authentication cookies  Limit session lifetime Session Management

Web Application  Privacy  Authenticity  Integrity  Authentication Cryptography

Web Application  Encrypt cookie state  Make sure that users do not bypass security checks  Validate all values sent from the client  Do not trust http header information Parameter Manipulation

Web Application  Don’t give the client unnecessary information  Log detailed error messages  Catch exceptions and handle them  Buffer over flow attacks Exception Management

Web Application  Log all key events  Secure log files  Back up and analyze log files  One application to use BIG-IP ASM Logging Events