CSE4303 Introduction to Computer Security (Lecture 4)

Network attacks

Examining the transport layer

Transmission Control Protocol (TCP)

Connection-oriented, preserves order

• Sender
  • Break data into packets
  • Attach packet numbers
• Receiver
  • Acknowledge receipt; lost packets are resent
  • Reassemble packets in correct order

Security Problems

1. Network packets pass by untrusted hosts
   • Eavesdropping, packet sniffing
   • Especially easy when attacker controls a machine close to victim (e.g. WiFi routers)
2. TCP state easily obtained by eavesdropping
   • Enables spoofing and session hijacking
3. Denial of Service (DoS) vulnerabilities