CS2005 - Lecture 12 - Security

Masquerading attack

Pretending to be another entity

What are the four main types of security violations?

1. Breach of confidentiality (unauthorised data access)

2. Breach of integrity (unauthorised data modification)

3. Breach of availability (unauthorised data destruction)

4. Theft of service (unauthorised resource use)

Replay attack

Maliciously resending valid data

Man-in-the-middle

Intercepting and altering communications

At which 4 levels must security be implemented?

1. Physical (data centres, hardware)

2. Human (prevent social engineering)

3. Operating System (protection mechanisms)

4. Network (secure communications)

Trojan Horse

Disguised malware e.g. fake login

Logic Bomb

Triggers under specific conditions

Buffer Overflow

Overwrites memory to exploit

Virus

Self-replicating code infects files

Symmetric Encryption

Uses one shared skey to encrypt/decrypt

Asymmetric Encryption

Uses public key (encrypt) and private key (decrypt)

RSA encryption

Generate primes p and q; compute N=p*q Public key: (ke, N) Private key: (kd, N)

Worms

Self-replicating malware e.g. Morris worm

DoS attacks

Overloads systems to deny service e.g. traffic floods

Plaintext

Original message

Ciphertext

Encrypted message

Cipher

Algorithm for encryption/decryption

Cryptography

Prevents eavesdropping/spoofing by ensuring:

- Confidentiality (only authorised parties read data)

- Authentication (verify sender/receiver)