CS 116: Introduction to Security

Tufts University Department of Computer Science, Fall 2025

Course Description

A holistic and broad perspective on cyber security. Attacking and defending networks, cryptography, vulnerabilities, reverse engineering, web security, static and dynamic analysis, malware, forensics. Principles illustrated through hands-on labs and projects, including Capture The Flag (CTF) games.

Sections

In-person, undergrads and grads: Tuesdays, 4:30 - 5:45 PM EST in Braker Hall Room 1; Thursdays on Twitch, 4:30 - 5:45 PM EST
Online Master's in Computer Science: live sessions on Wednesdays, 5:30 - 7:00 PM EST (via Zoom)

Instructor

Ming Chow, ming.chow@tufts.edu
In-Person Office Hours: Tuesdays, 3:00 - 4:15 PM EST in JCC, fourth floor --by the kitchen area

Prerequisites

CS 15 or Data Structures equivalent course. Recommended (not required) that you have taken CS 30 or 40. Please disregard prerequisite that CS 40 is required as listed in the University's bulletin as they are incorrect!

Hardware and Software for This Class (on your personal computer)

Absolute Requirements

A modern web browser (e.g., Firefox, Google Chrome, Chromium, Safari, Microsoft Edge)
A command line interface to run Unix/Linux commands (e.g., macOS, Windows with Linux Subsystem, a Linux-based virtual machine, a Docker container)

List of Security Tools That Will Be Used in Course

The following is a list of security tools that will be used in the course. All of these tools are platform-independent.

Wireshark
Nmap
Netcat
Python
Scapy
John the Ripper
Burp Suite
apktool and Java as apktool requires Java

Assessment

Labs (80%)
Quizzes (20%; there will be two)

Course Infrastructure

Lab submissions: Canvas (Tufts UTLN required)
Quizzes: Canvas (Tufts UTLN required)
Announcements: Piazza
Discussions: Piazza

Syllabus

Important note: always follow Canvas for due date on labs!

Topic 1, starting week of Tuesday, September 2nd	Course Introduction - By the end of this week, students will learn many of the fundamental Linux commands, an important skill for any good security practitioner, by playing Capture The Flags via OverTheWire. Students will remember the three principles of the CIA triad, critical to any organization's security infrastructure. Readings and Videos Thursday, September 4th: The Command Line Interface On Twitch On YouTube with Closed Captioning	Lab 1: Working with the Command Line Publicly accessible version of Lab 1
Topic 2, starting Tuesday, September 9th	Networking and Packets - By the end of this week, students will be able to dissect packet captures (PCAPs), network traffic. Readings and Videos Thursday, September 11th: Packet Analysis Using Wireshark On Twitch On YouTube with Closed Captioning	Lab 2: Packet Sleuth Publicly accessible version of Lab 2
Topic 3, starting Tuesday, September 16th	Attacking Networks - By the end of this week, students will perform network reconnaissance and port scanning, and build a rudimentary Security Information and Event Management (SIEM) / intrusion detection system (IDS). Readings and Videos Thursday, September 18th: Reconnaissance using Ping, Netcat, and Nmap On Twitch On YouTube with Closed Captioning Thursday, September 25th: Distributed Denial of Service (DDoS) Attacks and Scapy feat John Hammond On Twitch On YouTube with Closed Captioning	Lab 3: Scanning and Reconnaissance Publicly accessible version of Lab 3 Lab 4: Snake Oil, The Incident Alarm Publicly accessible version of Lab 4
Topic 4, starting Tuesday, September 30th	Cryptography - By the end of this week, students will be able to crack passwords on a Linux or Windows system, use one-way hash functions, and briefly describe how Transport Layer Security works. Readings and Videos Thursday, October 2nd: Passwords and Password Cracking with John the Ripper On Twitch On YouTube with Closed Captioning	Lab 5: Password Cracking Contest opens, due on Halloween (Friday, October 31st) at 11:59 PM PST
Topic 5, starting Tuesday, October 7th	Vulnerabilities - By the end of this week, students will know the difference between CVE and CWE. Readings and Videos Thursday, October 9th: Vulnerability Scanning, Exploitation, Badness-O-Meter On Twitch On YouTube with Closed Captioning	Quiz 1 open on Monday, October 6th; due Sunday, October 12th at 11:59 PDT
Topic 6, starting Tuesday, October 14th	Web Security - By the end of this week, students will able to perform and defend against the following attacks: Cross-Site Scripting (XSS), SQL injection, Cross-Site Request Forgery (CSRF), session hijacking, cookie tampering, directory traversal, command injection, remote and local file inclusion. Readings and Videos Thursday, October 16th: SQL Injection and Web Proxies On Twitch On YouTube with Closed Captioning Thursday, October 23rd: The Mistakes You Can't Make On Twitch On YouTube with Closed Captioning	Lab 6: The XSS Game Publicly accessible version of Lab 6 Lab 7: Gain Access to Website Publicly accessible version of Lab 7
Topic 7, starting Monday, October 27th	The Capture The Flags (CTF) Game Played Online - By the end of this week, students will be able to find and take advantage of a number of vulnerabilities on a live web application. Readings and Videos	Lab 8: The CTF Write Up Publicly accessible version of Lab 8
Topic 8, starting Tuesday, November 4th	Static and Dynamic Analysis - By the end of this week, students will be able to perform static analysis and dynamic analysis scans on software, write a technical risk analysis that is communicated to upper management. Readings and Videos Thursday, November 6th: Really, Really Bad Code and Static Analysis On Twitch On YouTube with Closed Captioning	Lab 9: Technical Risk Analysis
Topic 9, starting Thursday, November 13th	Malware - By the end of this week, students will be able to describe types of malware, see certain malware behaviors, scan and analyze malware, reverse engineer Android apps to determine if they are malicious. Readings and Videos Thursday, November 13th: Malware and Malware Analysis On Twitch On YouTube with Closed Captioning	Lab 10: Android Malware Analysis Publicly accessible version of Lab 10
Topic 11, starts Tuesday, December 2nd	~~The Future: Nihilism or Hope? - By the end of this week, students shall debate and ponder the hard questions in security, and be able to argue multiple viewpoints.~~ Lessons Not Learned: We Can't Even Get the Basics Right Readings and Videos Thursday, December 4th: Opportunities, Where Do You Go From Here On Twitch On YouTube with Closed Captioning	Quiz 2 open on Monday, December 1st; due Sunday, December 7th at 11:59 PM PDT

Frequently Asked Questions

Q: Is there a textbook for this course?

A: No

Q: Are there teaching assistants (TAs) for this course?

A: No

Q: What is the workload of this course?

A: Here is a list of all the labs with expected length and difficulty:

Lab 1: Working with the Command Line, Long (3+ hours) --you can put in as much time as you want on this lab
Lab 2: Packet Sleuth, Medium (1 - 3 hours)
Lab 3: Scanning and Reconnaissance, Your mileage may vary on this lab, could be 30 minutes, could be 2 hours or more. NOTE: This lab cannot be made publicly available because an actual target is used.
Lab 4: Python and the Incident Alarm, Long (3+ hours) to Impossible
Lab 5: The Password Cracking Contest, If you crack all the password hashes (read: good luck with that), you will receive an automatic "A" in the course
Lab 6: The XSS Game, Medium to Long.
Lab 7: Gain Access to Website, Very short. NOTE: This lab cannot be made publicly available because an actual target is used.
Lab 8: The CTF Game, One week --team based. NOTE: This lab cannot be made publicly available because an actual target is used.
Lab 9: Technical Risk Analysis, Short to Medium.
Lab 10: Android Malware Analysis, Short to Medium.

Q: Does this course count towards the M.S. in Cybersecurity and Public Policy?

A: Yes

Q: Does this course count towards the M.S. in Software Systems Development?

A: Yes. In fact, this is one of the four required courses for the M.S.

Q: Did you remove information on using Kali virtual machine for this class? If so, why?

A: Yes. After all these years, it was more trouble than it was worth. Further reasons:

Accessibility. For students who are visually impaired, using a virtual machine can be very difficult.
Not all students have a capable laptop. Sometimes due to financial reasons, some students use Chromebooks. The tools required for this course can be installed natively on macOS, Windows, and Linux.
Performance. Sometimes, using a VM can be very slow. A VM also do not use native drivers (e.g., for networking).
Hard disk space requirement: at least 10 GB necessary.
Apple M1 Macs cannot run most Intel x86 virtual machines.

Q: Is Piazza used in this course?

Yes, quite a lot

Q: Why is there a course website and a course Canvas? If you say "it is a nuisance for students to use multiple websites and services for one course", what gives?

This course website serves a few critical purposes. Years ago, I made a decision to make all the readings, slide decks, and most of the labs publicly available. The reasons: (1) to show that Tufts is serious and is working on Cyber Security matters, (2) to provide learning material to the public on Cyber Security as the Cyber Security education problem is very dire, (3) for recordkeeping on what is taught and not taught in this Security class --this comes up often when we speak to industry and organizations who want to work with Tufts on Cyber Security-related matters. The Canvas site for this course isn't made publicly available. Even if Canvas site was made publicly available, content is behind a walled garden, and (4) for redundancy if Canvas goes down.

Q: I have not taken a course on Networks (CS 112), Operating Systems (CS 111), or Computer Architecture (CS 40) yet. Is that a problem?

No. Cyber Security is a very broad field and it is impossible for anyone, even professionals, to know everything. What is important for you is to start thinking about Security.

Q: Will videos be recorded in case I miss class?

If you miss the in-person Tuesday classes due to illness or personal matters, you can always watch the recorded Wednesday sessions for online Master's students (Wednesday sessions are always recorded). Tuesday and Wednesday sessions are practically identical. Thursdays are on Twitch which are recorded and also exported to YouTube.

Q: If I am taking this course for professional purpose, can I have a tuition reimbursement letter or certificate?

A: Absolutely! It's a nice tuition reimbursement letter, hand signed!

If you have read this far, send me an email (ming.chow AT tufts DOT edu) with the subject "How's Kermit the Frog doing?" to earn a reward.

Course Policies

Labs

With the exception of the password cracking lab and CTF writeup, all labs for a given topic, are due on a Sunday at 11:59 PM PDT (that is, Pacific Time).
With the exception of password cracking lab, the CTF game, and quizzes, you are granted an automatic extension of 24 hours at no cost (i.e., grace period). A lab or quiz submitted after the grace period will not be accepted.
No extension tokens.

Accessibility Statement

Tufts is committed to providing equal access and support to all qualified students through the provision of reasonable accommodations so that each student may fully participate in the Tufts experience. If you have a disability that requires accommodations, please contact the StAAR Center (formerly SAS) staarcenter@tufts.edu or 617-627-4539 to make an appointment to determine appropriate accommodations. Please be aware that accommodations cannot be enacted retroactively, making timeliness a critical aspect for their provision. You can learn more about the StAAR Center at https://students.tufts.edu/student-accessibility-services.

NEW Starting Fall 2025: House Rules

You lose two full letter grade if you ask if there is a final exam (during the final exam period) in this course.
For each lab, you have unlimited submissions --prior to marked due date and time on Canvas. If I grade your lab before due date and time, and you make mistakes, you can resubmit for regrading. I call this "Advanced Grading."
There is a Tufts CS Discord. If you DM me on an academic issue (anything pertaining to grades or coursework), I will block you. This Discord is for anything other than academics.
There is no class on the week of Thanksgiving. In this case, week of November 24th. Book your travel now.
If you want your resume reviewed, just email it me and be sure to attach a PDF copy.
Don't call me "Professor", just address me by my first name. Thank you.

Expectations and Structure of This Course

This course will be a fun one for sure. A few notes on the expectations and structure of this course:

1. You are responsible for your own learning.

A very important point: if you want everything gone over in lecture or in notes, then this is not the course for you. More importantly, that's not how things work in real life.

2. You will learn by doing.

Each week, there will be at most three labs to hone your skills and to aim at the crux of the matter for the week. Here's an analogy: you don't learn how to cook simply by just reading cookbooks and watching YouTube videos. You learn by making, using your hands, and making mistakes.

3. You will learn by asking questions.

It is your responsibility to ask questions early and to ask for help...

4. ...and I expect discussions online to be very active and civil.

Share thoughts and respond to other people's questions. I will be online constantly. It is no secret that I respond very quickly unless I need to be away.