Matakuliah
Tahun
Versi
: H0242 / Keamanan Jaringan
: 2006
:1
Pertemuan 03
Ancaman dan Serangan
1
Learning Outcomes
Pada akhir pertemuan ini, diharapkan
mahasiswa akan mampu :
• Mahasiswa dapat memperhitungkan
ancaman dan serangan terhadap jaringan
2
Outline Materi
• Mekanisme Terjadinya Serangan
• Metode Pencegahan Serangan
3
Security Goals
Confidentiality
Integrity
Avaliability
4
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.
5
Types of Attacks
Passive Threads
Release of
Message Contents
Traffic
Analysis
Active Threads
Masquerade
Replay
Modification of
Message Contents
Denial of
Service
6
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.
7
Security Attacks
8
IPv4 Infrastructure
• No authentication for the source
• Various approaches exist to address
the problem:
– Router/firewall filtering
– TCP handshake
9
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.
10
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
11
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
12
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!
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The Security Life Cycle
• The iterations of
– Threats
– Policy
– Specification
– Design
– Implementation
– Operation and maintenance
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