1 Class 15 System Security

Outline Security Threats (External: malware, spoofing/phishing, sniffing, & data theft: Internal: unauthorized data access, theft) Intrusion detections system Firewall Encryption Digital certificate Secure Sockets Layer/Transport Layer Security Defenses against internal security threats 2

3 Systems Vulnerability Digital data: Can be duplicated/changed without being detected Network-related challenges: Connected to LANs, WANs (Internet) Anyone from inside/outside the organization can attempt to infiltrate information systems Electronic data pros: Integration, universal access vs. security con: Greater risk of unauthorized access, security vulnerability of IS

Security Threats - External 4 Data theft Defense: Encryption False identity (spoofing/phishing) Malware (virus, worm) Powerouttage, Natural disaster Defense: Plan, facilities Defense: Cautious user Defense: Anti-virus software, Firewall Sniffing Defense: Intrusion detection system

55 Defenses For Malware, defense is Firewall. Placed between internal LANs and external networks Uses rules that dictate what comes in and what goes out. Can be built into operating system. For data theft, defense is Intrusion Detection System. Automatically detects suspicious network traffic

6 Defenses: Encryption Encryption = Scrambling of messages to prevent authorized parties to read them. Encryption is a defense against sniffing communications channel. Single key encryption – Sender and receiver use the same private key for encryption and decryption Double key encryption – Sender and Receiver use a combination of a public and a private key: Digital Certificate - public key and a proof of its validity issued by a certificate authority (e.g., VeriSign); licensed annually. Encrypt with Recipient’s Public Key Decrypt with Recipient’s Private Key Digital Certificate Digital Signature can be applied Certificate Authority

Communications between client and server on the Internet happen over Secure Socket Layer (SSL) (current name: Transport Layer Security)- Internet protocol for securing data transfer. Negotiations about security, encryption, public key transfers – all happens on SSL/TSL. Supported by operating systems and Web browsers and servers. Wireless networks are more difficult to protect. If you use a wireless LAN at home you are on the Internet as soon as you connect a computer to a router! 7 Defenses on the Internet

88 Internal Security Threats & Defenses Theft (stealing data hardware, software) Unauthorized access to data (read, change, delete) Human error (leaving data unprotected, poor & lost passwords, not locking data/hardware/software) Defenses: Physical securing Managing access to data (system administrators) Training, supervision