Dr. Md. Shariful IslamAssociate Professor (IIT, DU)

Ashis Kumar ChandaMS Student (JN - 343)

Dept. of Computer Science & EngineeringUniversity of Dhaka

Information Security

Secure Software Design

Contents

Introduction

Common flaws

S-SDLC

Developer - Security tester

Security Model

Introduction

Security is the first concerning criteria in software development

A single feature can create a lot of trouble

Two groups – software developer & information security staff

Don’t stand

so close to me

Come together (right now)

10 common flaws

1. Earn or give, but never assume, trust.2. Use an authentication mechanism that cannot be bypassed or tampered with.3. Authorize after you authenticate.4. Strictly separate data and control instructions, and never process control instructions received from untrusted sources.5. Define an approach that ensures all data are explicitly validated.

10 common flaws

6. Use cryptography correctly.7. Identify sensitive data and how it should be handled.8. Always consider the users.9. Understand how integrating external components changes your attack surface.10. Be flexible when considering future changes to objects and actors.

Security Principles

AuthenticationWho a user is

Authorization What a user can do

Confidentiality What a user can see

Non-repudiation Did a user really perform an action

Availability The system is ready for user activity

“I already apply all those principles in my design…”

Model Security !

Bugs?

Security Model

Techniques to evaluate an application’s overall security or assess the impact of a specific threat

Objectively identify vulnerabilities and address countermeasures

Integrated steps to take in the development process

… but wait. There’s more !

Buffer OverflowsInsecure Configuration ManagementInsecure StorageUnnecessary and Malicious Code Unauthorized Information Gathering Broken Caching, Pooling, and Reuse

Look at to the core source of the problem and not the symptoms

References

• Bridging the Gap between Software Development and Information Security - KENNETH R. VAN WYK, GARY MCGRAW

• G. Hogland and G. McGraw, Exploiting Software: How to Break Code, Addison-Wesley, 2004.

• J. Koziol et al., The Shellcoder’s Handbook: Discovering and Exploiting Security Holes, John Wiley & Sons, 2004.

• D. Farmer and W. Venema, Forensic Discovery, Addison-Wesley, 2004

THANKS