1 Pertemuan 03 Ancaman dan Serangan Matakuliah: H0242 / Keamanan Jaringan Tahun: 2006 Versi: 1

2 Learning Outcomes Pada akhir pertemuan ini, diharapkan mahasiswa akan mampu : Mahasiswa dapat memperhitungkan ancaman dan serangan terhadap jaringan

3 Outline Materi Mekanisme Terjadinya Serangan Metode Pencegahan Serangan

4 Security Goals Integrity Confidentiality Avaliability

5 Security Threats and Attacks A threat is a potential violation of security. –Flaws in design, implementation, and operation. An attack is any action that violates security. –Active adversary. Common threats: –Snooping/eavesdropping, alteration, spoofing, repudiation of origin, denial of receipt, delay and denial of service.

6 Types of Attacks Passive ThreadsActive Threads Release of Message Contents Traffic Analysis MasqueradeReplayModification of Message Contents Denial of Service

7 Attacks, Services and Mechanisms Security Attack: –Any action that compromises the security of information. Security Mechanism: –A mechanism that is designed to detect, prevent, or recover from a security attack. Security Service: – A service that enhances the security of data processing systems and information transfers. A security service makes use of one or more security mechanisms.

8 Security Attacks

9 IPv4 Infrastructure No authentication for the source Various approaches exist to address the problem: –Router/firewall filtering –TCP handshake

10 Vulnerability A vulnerability (or security flaw) is a specific failure of the security controls. Using the failure to violate the site security: exploiting the vulnerability; the person who does this: an attacker. It can be due to: –Lapses in design, implementation, and operation procedures. –Even security algorithms/systems are not immune! We will go over some examples in this course.

11 IP Protocol Vulnerabilities Authentication based on IP source address –But no effective mechanisms against IP spoofing Consequences (possible exploits) –Denial of Service attacks on infrastructures IP Spoofing and SYN Flood Smurf and Fraggle attacks OSPF Max Sequence

12 Methods of Defence Encryption Software Controls (access limitations in a data base, in operating system protect each user from other users) Hardware Controls (smartcard) Policies (frequent changes of passwords) Physical Controls

13 Impact of Attacks –Theft of confidential information –Unauthorized use of Network bandwidth Computing resource –Spread of false information –Disruption of legitimate services All attacks can be related and are dangerous!

14 The Security Life Cycle The iterations of –Threats –Policy –Specification –Design –Implementation –Operation and maintenance