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Web Technologies-I

Notes Unit 14: Security

CONTENTS
Objectives
Introduction
14.1 Global Variables and Form Data

14.1.1 Initialize Variables
14.1.2 Set Variables Order
14.1.3 Data Filtering
14.2 Filenames
14.2.1 Check for Relative Paths
14.2.2 Restrict Filesystem Access to a Specific Directory

14.3 File Uploads
14.3.1 Beware of Filling Your Filesystem
14.3.2 Surviving register_globals
14.3.3 Distrust Browser-Supplied Filenames
14.4 File Permissions
14.4.1 Do not Use Files
14.4.2 Get It Right the First Time
14.4.3 Session Files

14.4.4 Safe Mode
14.5 PHP Code
14.6 Shell Commands
14.7 Summary
14.8 Keywords
14.9 Review Questions
14.10 Further Reading

Objectives

After studying this unit, you will be able to:
• Discuss about global variables and form data
• Understand file uploads in PHP

• Explain about file permissions in PHP
• Discuss about the PHP code
• Explain the shell commands in PHP

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