CS 2550 - Foundations of Cybersecurity

General Information

Professors: Christo Wilson
Classroom: Behrakis 310
Time: Tuesdays 11:45-1:25pm and Thursdays 2:50-4:30pm
Office Hours: Thursday 11am-2pm (or by appointment) in 615 ISEC
Teaching Assistants: Samir Elhelw, Walter Geanacopoulos, Matthew Kline, Martin Petrauskas, Garrett Tucker, Inbar Yaakobovich
TA Email: Samir, Walter, Matt, Martin, Garrett, Inbar
TA Office Hours: Tuesday 9:30-11:30am, Outside WVH 366 (look for Inbar)
Wednesday 1-5pm, ISEC 505
Friday 12-2pm, ISEC 505
Class Forum: On Piazza

Course Description

Major security breaches routinely make headline news and impact the lives of millions of people. Cybercrime is a multi-million dollar, mature business. Advanced, persistent threats posed by nation-state adversaries are beginning to impact critical infrastructure, and even democratic processes themselves. As technology becomes embedded in ever more facets of our lives, society, business, and government, the need for cybersecurity experts to protect our infrastructure grows.

This course presents an overview of basic cybersecurity principles and concepts, including systems and communications security. The high-level goal is to introduce the breadth of topics in the cybersecurity space to students, and begin training them to apply these ideas through understanding of defensive mechanisms and attacker strategies.

The course will cover essential security properties like confidentiality and integrity, as well as desirable properties like least privilege and defense in depth. Concepts will be illustrated with practical tools, systems, and applications that exemplify them. Hands-on projects will introduce students to key security tools and libraries.

Readings will introduce students to the history of hacking and cybersecurity, as well as contemporary threats. Students will learn how to develop threat models that characterize attacker capabilities, goals, and the costs of different defensive strategies.

The course will also introduce students to legal, ethical, and human factors issues associated with cybersecurity.


The official prerequisite for this course is CS 2500. I expect students to be able to implement relatively straightforward programming assignments, i.e. ones that will not require hundreds of lines of complicated code. I strive to make my programming assignments as language agnostic as possible, but I will be using Python for in-class examples.

Basic knowledge of the Unix/Linux command line is essential. You should know how to write code using emacs/vim, write a makefile, compile code using makefiles, use SSH and SCP, write very simple shell scripts, check for running processes, kill runaway processes, and create compressed archives.

Since CS 3650 (Computer Systems) and CS 3700 (Networks and Distributed Systems) are not prerequisites, you will not be expected to complete assignments that deal with assembly code, operating system internals, or low-level network protocols. If you expect to be doing binary exploitation in this class, you will be disappointed; you'll have to wait for CS 3740 (Systems Security) and CS 4740 (Network Security) for that stuff.

Class Forum

The class forum is on Piazza. Why Piazza? Because they have a nice web interface, as well as iPhone and Android apps. Piazza is the best place to ask questions about projects, programming, debugging issues, exams, etc. To keep things organized, please tag all posts with the appropriate hashtags, e.g. #lecture1, #project3, etc. I will also use Piazza to broadcast announcements to the class. Bottom line: unless you have a private problem, post to Piazza before writing me/the TA an email.


In this class, you will learn about security techniques and tools that can potentially be used for offensive purposes; "hacking" in other words. It is imperative that students only use these tools and techniques on systems they own (your personal computers) or systems that are sanctioned by the instructor. NEVER perform attacks against public systems that you do not control. As we will discuss in class, it is ethically problematic to attack systems that you do not own, and may violate the law.

Lecture Format and In-class Prep

This class will use a traditional, lecture-style format, punctuated with in-class examples. Slides are available in the course schedule below.

I recommend that students bring a laptop to class that has access to a local Unix/Linux-style command line. You can rely on SSH or PuTTY to get a remote command line on the Khoury College machines, but you run the risk of Wifi connection issues leaving you unable to work. macOS users should be able to use the default Mac command line and Homebrew; Windows users can install Linux in a virtual machine, or, if you have a recent version of Windows 10, you can install the Windows Subsystem for Linux (WSL) and then download a copy of Ubuntu right from the Windows Store.

Schedule and Lecture Slides

Dates Slides Readings Comments
Jan. 7-11 Intro, History, Threat Modeling Start Ghost in the Wires
Jan. 14-18 Linux Basics Proj. 0 Due Jan. 18
Jan. 21-25 Cryptography
Jan. 28-Feb. 1 Authentication and Passwords Proj. 1 Due Feb. 1
Feb. 4-8 Access Control Finish Ghost in the Wires
Feb. 11-15 Social Engineering Proj. 2 Due Feb. 15
Feb. 18-22 Cyberlaw and Ethics
Feb. 25-Mar. 1 Midterm: February 26, Slack Day Proj. 3 Due Mar. 1
Mar. 4-8 Spring Break Start Countdown to Zero Day
Mar. 11-15 Systems Security
Mar. 18-22 Exploits
Mar. 25-29 Infection Vectors, Cybercrime Underground Proj. 4 Due Mar. 29
Apr. 1-5 Botnets, DDOS Finish Countdown to Zero Day
Apr. 8-12 Web Privacy (PDF, Keynote) Proj. 5 Due Apr. 12
Apr. 15-19 Slack Day Final Exam 10:30-12:30, WVF 020, Apr. 19, Proj. 6 Due Apr. 26


I do not require students to get textbooks. However, there are two books that will be required reading during this course:

You are free to purchase paper or electronic versions of these books.

There will be additional readings from online articles and academic papers. These will be made available via this webpage.


There will be seven projects throughout the semester. Assignments are due at 11:59:59pm on the specified date. You will use a turn-in script to create a compressed archive of the necessary files for the assignments, timestamp them, and submit them for grading. I highly recommend that students start assignments early!

Assignment Description Due Date Piazza Tag % of Final Grade
Project 0 Linux Basics Friday, January 18 #project0 4%
Project 1 Cryptography Friday, February 1 #project1 6%
Project 2 Passwords Friday, February 15 #project2 10%
Project 3 Social Engineering Friday, March 1 #project3 10%
Project 4 Fuzzing Friday, March 29 #project4 10%
Project 5 Exploits Friday, April 12 #project5 10%
Project 6 Forensics Friday, April 26 #project6 10%

Most projects can be programmed in a language of your choice. The only universal requirement is that your projects must compile and run on an unmodified Khoury College Linux machine. Notice the stress on unmodified: if you're relying on libraries or tools that are only available in your home directory, then we will not be able to run your code and you will fail the assignment. You are welcome to develop and test code on your home machines, but in the end everything needs to work on the Khoury College Linux machines. If you have any questions about the use of particular languages or libraries, post them to Piazza.


There will be one midterm and one final. All exams will be closed book, and computers are not allowed nor is any access to the Internet via any device. Students are allowed to bring a single 8.5x11 cheat sheet to exams, with material written or printed on the front and back. The exams will cover material from lectures, readings, and the projects. The final will be cumulative, so review everything!


Throughout the semester, there will be five in-class quizzes. These quizzes will be brief; they are designed to be completed in 15 minutes or less. They are not meant to cause students grief, and the questions will be straightforward. The goals of the quizzes are to incentivize attendance and encourage careful study of the lecture material. If you need to miss class for any reason, please let me know ahead of time, just in case there is a quiz. Makeups will be provided on a needs-driven basis.


I do not require students to attend class and I won't be taking attendance, although as stated above, there will be in-class quizzes. That said, I prefer an interactive classroom, and I encourage everyone to attend, ask questions, and participate!


Projects (7): 4%, 6%, 10%, 10%, 10%, 10%, 10%
Quizzes (5): 2% each
Midterm and Final: 15% each

Each assignment will include a breakdown of how it will be graded. Some projects may include extra credit components that can boost your grade above the maximum score :)

To calculate final grades, I simply sum up the points obtained by each student (the points will sum up to some number x out of 100) and then use the following scale to determine the letter grade: [0-60] F, [60-62] D-, [63-66] D, [67-69] D+, [70-72] C-, [73-76] C, [77-79] C+, [80-82] B-, [83-86] B, [87-89] B+, [90-92] A-, [93-100] A. I do not curve the grades in any way. All fractions will be rounded up.

Requests for Regrading

In this class, we will use the Coaches Challenge to handle requests for regrading. Each student is allotted two (2) challenges each semester. If you want a project or a test to be regraded, you must come to the professors office hours and make a formal challenge specifying (a) the problem or problems you want to be regraded, and (b) for each of these problems, why you think the problem was misgraded. If it turns out that there has been an error in grading, the grade will be corrected, and you get to keep your challenge. However, if the original grade was correct, then you permanently lose your challenge. Once your two challenges are exhausted, you will not be able to request regrades. You may not challenge the use of slip days, or any points lost due to lateness.

Note that, in the case of projects, all group members must have an available challenge in order to contest a grade. If the challenge is successful, then all group members get to keep their challenge. However, if the challenge is unsuccessful, then all group members permamently lose one challenge.

Late Policy

For programming projects, we will use flexible slip days. Each student is given four (4) slip days for the semester. You may use the slip days on any project during the semester in increments of one day. For example, you can hand in one project four days late, or one project two days late and two projects one day late. You do not need to ask permission before using slip days; simply turn in your assignment late and the grading scripts will automatically tabulate any slip days you have used.

Slip days will be deducted from each group member's remaining slip days. Keep this stipulation in mind: if one member of a group has zero slip days remaining, then that means the whole group has zero slip days remaining.

After you have used up your slip days, any project handed in late will be marked off using the following formula:

Original_Grade * (1 - ceiling(Seconds_Late / 86400) * 0.2) = Late_Grade

In other words, every day late is 20% off your grade. Being 1 second late is exactly equivalent to being 23 hours and 59 minutes late. Since you will be turning-in your code on the Khoury College machines, their clocks are the benchmark time (so beware clock skew between your desktop and Khoury College if you're thinking about turning-in work seconds before the deadline). My late policy is extremely generous, and therefor I will not be sympathic to excuses for lateness.

Cheating Policy

It's ok to ask your peers about the concepts, algorithms, or approaches needed to do the assignments. We encourage you to do so; both giving and taking advice will help you to learn. However, what you turn in must be your own, or for projects, your group's own work. Looking at or copying code or homework solutions from other people or the Web is strictly prohibited. In particular, looking at other solutions (e.g., from other groups or students who previously took the course) is a direct violation. Projects must be entirely the work of the students turning them in, i.e. you and your group members. If you have any questions about using a particular resource, ask the course staff or post a question to the class forum.

All students are subject to the Northeastern University's Academic Integrity Policy. Per Khoury College policy, all cases of suspected plagiarism or other academic dishonesty must be referred to the Office of Student Conduct and Conflict Resolution (OSCCR). This may result is deferred suspension, suspension, or expulsion from the university.

Accommodations for Students with Disabilities

If you have a disability-related need for reasonable academic accommodations in this course and have not yet met with a Disability Specialist, please visit www.northeastern.edu/drc and follow the outlined procedure to request services. If the Disability Resource Center has formally approved you for an academic accommodation in this class, please present the instructor with your "Professor Notification Letter" at your earliest convenience, so that we can address your specific needs as early as possible.

Title IX

Title IX makes it clear that violence and harassment based on sex and gender are Civil Rights offenses subject to the same kinds of accountability and the same kinds of support applied to offenses against other protected categories such as race, national origin, etc. If you or someone you know has been harassed or assaulted, you can find the appropriate resources here.