This lecture consider briefly how the role of firewalls in network security has evolved. It also explores how TLS provides confidentiality, integrity and authenticity in the transport layer, and it discusses some of the problems discovered in TLS implementations. Finally, it considers how IPSec provides similar benefits to TLS, but in the Internet layer.

• Lecture video
• Slides (PDF)
• Exercises:
  • Network Scanning
• Other resources:
  • Chapter 5 of Bellovin’s Thinking Security: Stopping Next Year’s Hackers
  • Example of a firewall vulnerability (CVE-2016-1287)
  • RFC 5246, the TLS 1.2 specification
  • The OpenSSL library
  • Fahl et al, Why Eve and Mallory love Android: An Analysis of Android SSL (In)Security (PDF)
  • Recent problems with TLS or implementations:
    • 2014: Heartbleed website and reminiscences
    • 2016: DROWN, Sweet32
    • 2022: OpenSSL buffer overruns