This book provides the readers the following insights into how: • Websites are hacked by exploiting command injection, file inclusion, file upload and other vulnerabilities. • Databases are compromised by basic and advanced SQL injection. • Browser clients are targeted by Cross-Site Scripting attacks. • Linux computers are breached by exploiting their vulnerabilities without recourse to social-engineering. • Forensic tools can be used to detect malicious intrusions in to systems. • Data in transit can be safeguarded by cryptographic and other mechanisms. • And cyber security tools that can be deployed against the above described cyber-attacks.