Attack Prevention

All measures taken in order to avert that an attacker succeeds in realizing a threat Examples: • Cryptographic measures: encryption, computation of modification detection codes, running authentication protocols, etc. • Firewall techniques: packet filtering, service proxying, etc. Preventive measures are by definition taken before an attack takes place Attention: it is generally impossible to prevent every potential attack! Network Security, WS 2008/09, Chapter 9 5 Prevention: Defense Techniques Against DoS Attacks (1) Defenses against disabling services: Hacking defenses: • Good system administration • Firewalls, logging & intrusion detection systems Implementation weakness defenses: • Code reviews, stress testing, etc. Protocol deviation defenses: • Fault tolerant protocol design • Error logging & intrusion detection systems • “DoS-aware protocol design”: – Be aware of possible DoS attacks when reassembling packets – Do not perform expensive operations, reserve memory, etc., before authenticatio