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Internet security for the home. Paul Norton MEng(Hons) MIEE Electronic engineer working for Pascall Electronics Ltd. on the Isle of Wight A talk on Internet security from the viewpoint of the home user…. Profile of the Home internet user. Traditionally, home internet usage has tended to be:-
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Internet security for the home Paul Norton MEng(Hons) MIEE Electronic engineer working for Pascall Electronics Ltd. on the Isle of Wight A talk on Internet security from the viewpoint of the home user…
Profile of the Home internet user. Traditionally, home internet usage has tended to be:- • Low bandwidth, billed per minute. • Short DHCP lease time. • For simple email, web access, chat. Increasing trends: • Higher bandwidth, always-on, fixed fee. • Longer leases. • Multimedia email, filesharing applications, more complex chat programs, remote assistance, etc.
What do we mean by security? • Keep private files private. • Prevent damage to/tampering with our operating system and computer. • Shop online safely. • Send and receive email safely. • Will not consider high-grade attacks in this talk.
Threats • Viruses • Backdoor programs • Denial of Service (DoS) • Interception
More about viruses • Some viruses exploit software flaws to run automatically. • Infection can come from a variety of sources • Damage.
Klez Virus • Klez-a detected by Sophos since Oct 2001. Top virus in 2002, still going strong. • Auto executes • Built-in mail engine. • Attaches files randomly • Attempts to disable AV. • Also spreads via network.
Backdoor programs / trojans • Program can do anything that a user sitting at the computer could do. • Infection. • DDOS.
Methods of protection • Anti virus • Password discipline • Firewalls
Passwords • Storing passwords is risky. • Passwords are recorded using a one-way function. • Brute force attack.
Why firewall? • To prevent the exploitation of backdoor programs. • Prevent unauthorised connection to services. • Prevents an attacker from scanning for a vulnerability
What does a firewall do? • A firewall filters the network to allow only certain types of packets. • Incoming connections. • Obviously forged packets. • ICMP danger.
Firewall examples • Zone Alarm • Smoothwall • Iptables • “Black box” firewalls.
Introduction to cryptography • 2 main forms, symmetric, and asymmetric. • Key verification. • Session keys.
Shopping online • SSL encryption (https) • Key verification • Cipher strength • Weaknesses
Secure email • Demo weaknesses. • Digital signature. • Encryption. • SSL
Summary • Backdoor programs and viruses pose threats • Antivirus and firewalls reduce the risk. • Traditional protocols may be unsafe. • Cryptography can be used to provide secure communication.
Basic introduction to Networking • IP identifies each computer individually • TCP identifies the service being used (www, ftp, email etc.) • DHCP is used to assign an IP address to a computer upon connection to the internet