Improving Web Application Security: Threats and - CGISecurity

Contents ixStep 3. Decompose the Application............................................................................ 52Identify Trust Boundaries ....................................................................................... 53Identify Data Flow ................................................................................................. 53Identify Entry Points .............................................................................................. 54Identify Privileged Code ......................................................................................... 54Document the Security Profile ................................................................................ 55Step 4. Identify the Threats ....................................................................................... 56Identify Network Threats........................................................................................ 57Identify Host Threats............................................................................................. 58Identify Application Threats.................................................................................... 58Using Attack Trees and Attack Patterns................................................................... 59Step 5. Document the Threats ................................................................................... 62Step 6. Rate the Threats ........................................................................................... 62Risk = Probability * Damage Potential .................................................................... 63High, Medium, and Low Ratings ............................................................................. 63DREAD ................................................................................................................. 63What Comes After Threat Modeling?........................................................................... 65Generating a Work Item Report .............................................................................. 66Summary ................................................................................................................. 66Additional Resources ................................................................................................ 66Part IIDesigning Secure Web Applications 67Chapter 4Design Guidelines for Secure Web Applications 69In This Chapter ......................................................................................................... 69Overview .................................................................................................................. 69How to Use This Chapter ........................................................................................... 70Architecture and Design Issues for Web Applications ................................................... 70Deployment Considerations ....................................................................................... 72Security Policies and Procedures............................................................................ 73Network Infrastructure Components ....................................................................... 73Deployment Topologies.......................................................................................... 73Intranet, Extranet, and Internet............................................................................... 74Input Validation......................................................................................................... 74Assume All Input Is Malicious ................................................................................ 75Centralize Your Approach ....................................................................................... 75Do Not Rely on Client-Side Validation...................................................................... 76Be Careful with Canonicalization Issues.................................................................. 76Constrain, Reject, and Sanitize Your Input ............................................................... 77In Practice............................................................................................................ 79