Network and Communications Security (IN3210/IN4210)

Introduction

Introduction

● Nils Gruschka− University Kiel (Diploma in Computer Science)

− T-Systems, Hamburg

− University Kiel (PhD in Computer Science)

− NEC Laboratories Europe, Bonn + Heidelberg

− University of Applied Science Kiel

− University of Oslo

● Contact:− nilsgrus@ifi.uio.no

● Areas of interest:− Security: Network, Web, Cloud Computing, Industrial Networks

− Privacy, Data Protection

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Nils Gruschka

Introduction

● Nils A. Nordbotten

− Cand.Scient and Ph.D. in informatics from UiO, and Executive Master of Management from BI Norwegian Business School

− Simula Research Laboratory (2003-2007)

− UniK-University Graduate Center (20 %) (2012-2014)

− Norwegian Defence Research Establishment (FFI) (2007-2020)

− University of Oslo (20 %) (2014-)

− Thales Norway (2020-)

● Contact

− n.a.nordbotten@its.uio.no

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Organisation

● “Cloned” course: IN3210 (Bachelor) + IN4210 (Master)

● Course page (also for IN4210):− https://www.uio.no/studier/emner/matnat/ifi/IN3210/h20/index.html

● Lecture− Home study: Pre-recorded lecture videos

− Online conference: Discussion and Q&A during the scheduled slots

● Workshop− Practical tasks, done individually or in groups

− Not mandatory, but helps understanding the concepts from the lecture

− Home work

− Online conference: Discussion and Q&A during the scheduled slots

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Organisation

● Canvas course:

− https://uio.instructure.com/courses/28965

● Quizzes:

− For every topic a “learning progress control” quiz is offered

− Not mandatory, but highly recommended

● Discussion board:

− Ask / answer course-wide questions

● Groups (will be activated mid of September):

− For the semester task

− Discuss and exchange files inside the group

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Examination

● Semester Task (in groups):

− IN3210: write a report

− IN4210: create a seminar presentation

● Written Exam (individually):

− 3 hour digital exam at home

● Both parts of the exam must be passed and must be passed in the same semester.

● Final Grade

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Semester Task 30%

Written Exam 70%

Semester Task (general)

● Select a network security topic (as a group):

− https://uio-my.sharepoint.com/:x:/g/personal/nilsgrus_uio_no/EbEqNbzhIN5AsA6zuFlCae8BAg0eOvDXtRz8jgDynPmNJQ?e=esDJ2P

● Deadline for selecting group and topic:

− 15. September

● (Optional) Propose own topics:

− Submit your proposal: https://nettskjema.no/a/158011

− Deadline for topic proposal: 31. August

− Approved topics will be added to the selection spreadsheet

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Semester Task (just IN3210)

● Group size: 2 or 3 students

● Write a (scientific) report on the selected topic

● Length: 4 – 5 pages per person

● Language: English or Norwegian

● Submission via Inspera (more info later)

● Submission deadline: 20. November

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Semester Task (just IN4210)

● Group size: 3 or 4 students

● Create a seminar presentation on the selected topic

● Presentation (submission of slides: 20. November)− Approx. 10 min per persons

− Performed via Zoom

− Presented to the whole course (teachers + students)

− During the scheduled slots in November (details soon)

− Language: English

● Handout (submission: 1 day before the talk)− 1 page, text + figures

− Summarizes the most important facts

● Final exam (IN3210 + IN4210) will contain questions from seminar talks!

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Exact length ofpresentations will be

announced end ofSeptember!

Semester Task (general)

● Scientific work:

− Used sources (books, article, online recourses) must be referenced (at end of the report/on the last slide of the presentation)

− Plagiarism → failed semester task → failed course

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Content

● Cryptography

● Certificates & PKI

● Transport Layer Security

● IP Security

● MAC Security

● Wireless LAN Security

● Email Security

● DNS Security

● Firewalls

● Routing Security

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Recommended Books

● https://link.springer.com/book/10.1007/978-3-642-04101-3

● https://link.springer.com/book/10.1007/978-1-4471-6654-2

● https://link.springer.com/book/10.1007%2F978-3-030-33649-3

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Questions?

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Introduction into (Network) Security

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What is Security?

Attacker

Threat

Assets

Counter-measure

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Computer Security

● Security of computers and networks

● Protection of digital assets

● Axioms of Computer Security:− Confidentiality (e.g. of transmitted secret information)

− Integrity (e.g. of stored data)

− Availability (e.g. of services)

● Further goals:− Authenticity

− Non-repudiation

− Privacy

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Motivations for attacks

● Financial advantages− Free of charge use service with costs

− Performing financial transactions

− → Spoofing different identity

● “Fun”− Challenging security systems

● “Revenge”− Vandalism

− Intrigues

● Political or religious motives

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Security Threats

● Examples for attacks

− Services:▪ Denial-of-Service

− Communication:▪ Eavesdropping

▪ Modification

− Stored data:▪ Espionage

▪ Deletion

▪ „Vandalism“

● Basic attack measureson communication− Sniffing

− Redirection, e.g.▪ ARP Spoofing

▪ DNS Poisoning

▪ Phishing

− Man-in-the-middle

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“Nomenclature”

● The “good” ones:

− Alice

− Bob

● The “bad” ones:

− Eve (passive attacker)

− Mallory (active attacker)

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Bob

Alice

Eve

Mallory

Sniffing

● Requires access to the communication medium

● Passive Attacks, e.g.:

− Eavesdropping

− Traffic analysis

Bob Alice

Eve

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Redirection

● Can be used as preparation for man-in-the middle attacks

Bob Alice

Eve / Mallory

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Man-in-the-middle

● Passive attacks (see „Sniffing“)

● Active attacks, e.g.− Packet drop

− Packet modification

− Packet injection

− Packet replay

AliceBob Eve / Mallory

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Adversary Model

● Important question:

− What capabilities do I assume for the attacker?

− What kind of attacks can the attacker perform?

● → Adversary model

● Required for implementing countermeasures/testing security protocols

● Typical adversary model (Dolev and Yao, 1983):

− The attacker can perform any of the aforementioned action on transmitted packets

− The attacker can not break “secure” algorithms (e.g. AES)

● Security schemes (e.g. cryptographic protocols) must guarantee their security goals in the presence of this attacker

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Attack Examples

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ARP

● Address Resolution Protocol

● Maps inside local networks from IP address to MAC address

10.0.0.8Who has 10.0.0.8?

10.0.0.8 = FA … B3

FA … B3

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ARP Spoofing (Redirection Attack)

10.0.0.8

Who has 10.0.0.8?

10.0.0.8 = DC … A710.0.0.24

FA … B3

DC … A7

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Denial-of-Service (DoS)

● Attacker tries to overload the target service or network

● → „Service Denial“ for legitimate users

● Attack can target different service layers:

− Network (e.g. gateway, TCP/IP stacks)

− Representation (e.g. XML processing)

− Application

− Database

● Attacker looks for the bottleneck inside the service processing chain!

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DoS Example: SYN Flooding

SYN

SYN ACK

ACK

SYN

SYN ACK

SYN

SYN ACK

SYN

SYN ACK

Client Server

Client Server

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DDoS: Distributed DoS

● Often executed by multiple attackers: Distributed Denial of service (DDoS)

● Either controlled by botnet or „crowd“

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DDoS: Mirai Botnet

● Millions of infected IoT devices (routers, IP cameras)

● Offers DDoS as a service: 50.000 devices for 2 weeks: 3000$ - 4000$

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DDoS: Mirai Botnet

● Illustrating the infection with Mirai

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DDoS: Mirai Botnet

● One victim

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Attack Examples

● ... many more to come throughout the class

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