Unit 1 notes · 5 topics, read straight through

Unit 1: Introduction to Security

Every topic in one read: the big idea, the notes, the figures and the exam traps. Practice comes after, on the Unit 1 review.

1.1 Understanding Social Engineering

Big ideaSocial engineering attacks the person, not the computer.

1. What social engineering looks like (1.1.A)

Many attacks start with a person, not a computer. Social engineering uses psychological tactics to manipulate someone into doing one of three things 1.1.A.1:

The adversary wants you to Example
Reveal sensitive information (called elicitation) “Confirm your date of birth so we can verify you.”
Download a malicious file “Your invoice is attached: invoice.zip”
Click a malicious link “Track your parcel here.”

It can happen face to face, but it usually arrives by email, text message or social media message 1.1.A.1.

Two tactics show up again and again 1.1.A.2:

  • Intimidation: the adversary threatens negative consequences if you do not comply. “Your account will be suspended.”
  • Urgency: the adversary gives you a reason to act quickly. “Reply within 10 minutes.”

Real view

Inbox message · a made-up example
From: IT Help Desk <[email protected]>1
Subject: URGENT: account locked in 2 hours2
We detected unusual activity on your account. Your account will be permanently deleted unless you verify your login now.3
Verify my accountLink really goes to: schoo1-portal-verify.example4
Reply with your password and the 6-digit code we just texted to your phone.5
  1. 1Look-alike sender."schoo1" uses the digit 1, not the letter l. It pretends to be information technology (IT) staff (authority, a Unit 2 tactic).
  2. 2Urgency [1.1.A.2]."in 2 hours" pushes you to act before you check whether it is safe.
  3. 3Intimidation [1.1.B.2]."permanently deleted" uses fear of a negative consequence.
  4. 4Malicious link [1.1.C.3].The button hides a fake address that captures your login credentials.
  5. 5Elicitation [1.1.A.1, 1.1.C.2].Asks for the password and one-time code, so the adversary can log in as you.
Anatomy of a phishing message: five red flags. Real messages often show only two or three.

2. Why the tactics work (1.1.B)

These tactics work because they use common psychological principles that influence everyone 1.1.B.1. One message can use both: a deadline (“today”, “within 10 minutes”) signals urgency, and a loss or punishment (“suspended”, “withheld”, “reported”) signals intimidation.

  • Intimidation taps into our natural dislike of bad outcomes. Pointing at a possible loss creates fear, and fear pushes people to act 1.1.B.2.
  • Urgency taps into our habit of reacting fast to time-sensitive needs. Under pressure we skip the pause where we would ask, “Is this reasonable? Is this safe?” 1.1.B.3

Detect: when a message makes you feel scared or rushed, treat that feeling as a red flag and slow down. Check through a channel you already trust, such as the official app, instead of the link in the message.

3. What victims can lose (1.1.C)

What the victim gives away What the adversary can do with it
Personal information: name, phone number, address (including the street or town you grew up in), workplace, pets’ names, birthdate 1.1.C.1 Impersonate the victim. Details like these are often the answers to website challenge questions.
A one-time password (OTP) or login code 1.1.C.2 Log in to the service as the victim.
A download or a click 1.1.C.3 Install malware, steal data saved in the web browser, or send the victim to a fake login page that captures their credentials.

Try it below on a real-looking email, then on a text message. Some parts are red flags and some are normal.

Exam trap

  • Match the impact to what the message asks for. A request for a pet's name and birthdate leads to impersonation, not malware.

Simulator and checkpoint for 1.1 →

1.2 Suspicious Website Logins

Big ideaWeak authentication is an open door. Long, random, unique passwords plus multifactor authentication (MFA) close it.

1. Signs of a password attack (1.2.A)

In an online password attack, the adversary makes login attempts against a device or service, trying common passwords, passwords that follow common patterns, or passwords stolen in earlier breaches 1.2.A.1.

Login records give it away. Watch for these signs 1.2.A.2:

  • Many failed attempts in a short time. A person mistypes once or twice. A tool fails dozens of times a minute.
  • Logins at unusual times, such as 3 a.m. for a student account.
  • Logins from unknown devices the user has never signed in from.

Real view

Sign-in log · one student account
RowTimeIP addressResultDevice
1Mon 19:05:12203.0.113.24SuccessLaptop
2Wed 20:41:37203.0.113.24SuccessLaptop
3Thu 03:12:01198.51.100.77FailedUnknown
4Thu 03:12:02198.51.100.77FailedUnknown
5 to 38… 34 more failed attempts in 40 seconds …
39Thu 03:12:43198.51.100.77FailedUnknown
40Thu 03:12:44198.51.100.77SuccessUnknown
41Sat 11:20:05203.0.113.24SuccessLaptop

Normal pattern: evenings and weekends, from 203.0.113.24 (home). Rows 1, 2 and 41 fit it.

Rows 3 to 40 show all three signs: 37 failed attempts in 42 seconds, an unusual time (3 a.m.), and an unknown device and internet protocol (IP) address.

Row 40: the adversary got in.

Anatomy of a login log: find the normal pattern first, then the rows that break it. The addresses are from ranges reserved for examples.

2. How weak passwords get cracked (1.2.B)

People are predictable. Common patterns include 1.2.B.1:

  • one or two words, then a two-digit number (often a year), then a special character at the end
  • names of family members or pets
  • personally significant dates

Adversaries use this. They collect personal details about the target, such as birthdays, anniversaries and pet names, build a dictionary of likely passwords from them, and let an automated tool submit the guesses 1.2.B.2. A public social media profile can hand them most of the list.

Guessing dictionary built from one public profile
# found online: dog "Mocha", born 2008, team "Falcons"
Mocha2008!
mocha08!
Falcons2008!
MochaFalcons08?   # still guessable: both words are public

3. Making authentication stronger (1.2.C)

  • Long, random, unique. Every account gets its own password. A password manager can generate and store them, or you can use a long, unique passphrase 1.2.C.1.
  • No personal words or numbers. Skip names, dates and anything meaningful to you 1.2.C.2.
  • Turn on multifactor authentication (MFA). MFA asks for extra proof of identity, such as a one-time code, on top of the password 1.2.C.3.

Prevent: a passphrase made of several random unrelated words is long and easy to remember. A password manager means you only have to remember one.

Exam traps

  • First find the normal pattern in a log, then name the rows that break it.
  • A long password reused on many sites is still unsafe: one leak unlocks every account.

Simulator and checkpoint for 1.2 →

1.3 Best Practices for Public Networks

Big ideaPublic Wi-Fi is convenient for adversaries too. Know the adversary, know the attack, verify before you connect.

New to network names (service set identifiers, SSIDs), access points and beacons? The Networking Basics session on wireless covers them in 10 minutes.

1. Who the adversaries are (1.3.A)

Adversaries can be grouped by skill 1.3.A.1:

Low-skilled High-skilled
Tools Use malicious tools made by others, often bought online Create new tools or modify existing ones to beat new defenses
Vulnerabilities Exploit known vulnerabilities Can also discover undocumented vulnerabilities, called zero days

Their motivations vary too: greed, desire for recognition, dedication to a cause, revenge, politics or beliefs 1.3.A.2.

2. Three wireless attacks (1.3.B)

Attack What the adversary does Result
Evil twin 1.3.B.1 Sets up their own wireless access point (WAP) with a service set identifier (SSID) similar or identical to the real network Victims who join it send their traffic through the adversary. Traffic using an encrypted protocol such as Hypertext Transfer Protocol Secure (HTTPS) stays unreadable, but unencrypted hypertext transfer protocol (HTTP) traffic, including passwords typed into HTTP login pages, can be read.
Jamming 1.3.B.2 Floods the area with a strong electromagnetic (EM) signal in the network’s frequency range Legitimate traffic between users and the access point is blocked: a denial of service (DoS) attack
War driving 1.3.B.3 Drives or walks around a target, detecting the network’s beacons Learns the type of wireless network and where the signal leaks outside the building

Evil twin: a look-alike network that captures your traffic

[1.3.B.1] The adversary's wireless access point (WAP) uses a name (SSID) similar or identical to the real one.

Path 1: meant to join

Your devicesees two similar names
joins
Real access pointSSID: SunCafe-WiFi
connects to
Internet

Path 2: actually joined

Your devicepicked the look-alike name
joins
Evil twin (adversary)SSID: SunCafe_WiFi · captures your traffic
passes traffic on to
Internet

Can the adversary read it? Encrypted traffic such as HTTPS: no. Unencrypted traffic and data such as domain name system (DNS) queries: can be exposed [1.3.C.2].

Evil twin: a look-alike network that captures your traffic.
Real view: two networks share one name. An adversary can copy the name and even the posted password, so a lock icon alone does not prove a network is real. Ask staff which is real before you join.

3. Protecting yourself on public Wi-Fi (1.3.C)

  • Match the name exactly. Confirm the network you join is exactly the one you meant to join 1.3.C.1.
  • Think about how sensitive your data is. Most internet protocols are encrypted, but some data, such as domain name system (DNS) queries, can still be exposed. Decide whether your data is sensitive enough to avoid joining unencrypted Wi-Fi 1.3.C.2.
  • Consider a virtual private network (VPN). A VPN encrypts all your traffic to the VPN operator’s system, so the network or service provider cannot view it. The trade-off: the VPN provider can 1.3.C.3.

Prevent: a VPN does not remove trust; it moves it. Choose a provider you trust as much as you would trust your internet provider.

Exam trap

  • Everyone losing Wi-Fi at once points to jamming. A look-alike network name points to an evil twin. Someone mapping your signal from the parking lot is war driving.

Simulator and checkpoint for 1.3 →

1.4 AI-Based Cybersecurity Attacks

Big ideaAI makes old attacks faster, cheaper and more convincing.

1. Six ways adversaries use AI (1.4.A)

AI-powered move What it enables
Cloned voice or digital avatar built from existing voice and image samples 1.4.A.1 Impersonating someone on a phone or video call, leading to financial loss or the sharing of sensitive or private information. The more organizations use voice-based authentication, the bigger the impact.
Generative AI writing phishing 1.4.A.2 Fluent messages in any language. Unnatural language used to help spot phishing; that clue is fading.
Prompts that extract data from an LLM 1.4.A.3 Sensitive information can leak from what users typed in or from the huge data sets used to train the model.
Poisoning training data: false information planted online 1.4.A.4 New or edited websites carry lies into LLM training sets, so the LLM repeats them.
AI reconnaissance 1.4.A.5 Tools scan social media and public websites to build a profile of a target fast.
AI-enhanced coding tools 1.4.A.6 Writing new malware, changing legitimate code to act maliciously, or finding vulnerabilities in large code bases.

Case file: the call from “home”

A student gets a video call. It looks and sounds like their older brother: “I lost my wallet, can you send me the code that just came to your phone?” The face moves naturally. The voice is right. Then the student asks for the family word. The call drops.

Anatomy of an AI voice-cloning scam, and where to stop it

[1.4.A.1, 1.4.A.5, 1.4.B] A relative gets a call that sounds exactly like you.

  1. 1ReconnaissanceAI scrapes voice clips from social media
    Share less voice and video publiclyfewer samples to clone (beyond the course and exam description, CED)
  2. 2Clone the voiceAI builds a digital avatar of the voice
    Turn on MFA [1.4.B.2]could stop a cloned voice alone from opening an account that uses voice authentication
  3. 3Impersonatecalls a relative with an urgent fake story
    Shared secret phrase [1.4.B.1]proves who is calling
  4. 4Impactfinancial loss, or sensitive data shared
Anatomy of an AI voice-cloning scam, and where defenses can break the chain.

2. Protecting against AI-augmented attacks (1.4.B)

  • Set up shared secrets with close friends and family: a word or phrase only the two of you know, used to verify identity in high-stakes moments 1.4.B.1.
  • Enable multifactor authentication (MFA). If a cloned voice gets past voice authentication, a second factor can still block the login 1.4.B.2.
  • Keep personal or sensitive data out of AI tools such as chatbots and virtual assistants. Some tools train on what you type, and adversaries could pull it back out 1.4.B.3.
  • Evaluate AI output carefully. Verify it with reputable, stable sources that are not AI-based 1.4.B.4.

Prevent: agree on your shared secret in person, never in a text or chat that could be read later.

Exam trap

  • A stronger password does not stop voice cloning. A shared secret or a second factor does.

Simulator and checkpoint for 1.4 →

1.5 Leveraging AI in Cyber Defense

Big ideaAI gives defenders scale and speed. Its recommendations are reviewed by a knowledgeable human before they are put in place.

1. AI as the defender’s assistant (1.5.A)

AI tool reviews It recommends A human checks first
Security configurations, such as firewall rules and access controls 1.5.A.1 More secure settings A knowledgeable security technician
Application code 1.5.A.2 Fixes for the vulnerabilities it finds A knowledgeable programmer
Detection needs for automated detection systems 1.5.A.3 New detection rules A knowledgeable detection engineer

The pattern is the same every time: AI suggests, a person who understands the system approves.

AI configuration review (suggestion only)
# port 22 is remote login; 10.0.5.0/24 means the 256 addresses 10.0.5.0 to 10.0.5.255
# current rule
allow  any  to  server:22   # remote login open to the whole internet
# suggested rule
allow  10.0.5.0/24  to  server:22   # only the admin network
Status: waiting for technician approval

AI suggests, a knowledgeable human decides

[1.5.A] Three ways defenders use AI tools. None skips the human review; each is implemented only after it.

  1. Security configurationsAI suggests safer firewall and access rules
    Reviewed first by a security technicianthen implemented
  2. Application codeAI finds vulnerabilities and suggests fixes
    Reviewed first by a programmerthen implemented
  3. Detection rulesAI suggests new rules for automated detection
    Reviewed first by a detection engineerthen added to the system

Faster threat detection and response [1.5.B]

Millions of eventstoo many for humans to check
AI sorts them
Likely malicious vs harmless
then
Alert security staffor take a corrective action
AI suggests, a knowledgeable human decides.

2. Faster, more accurate detection (1.5.B)

  • Networks produce millions of digital events every day. A few are probably an adversary at work, and humans cannot inspect them all 1.5.B.1.
  • AI tools can be trained to sort events quickly into likely malicious and harmless 1.5.B.2.
  • They can be programmed to alert human staff or to take specific corrective actions depending on the type of activity 1.5.B.3.
  • The result: teams catch malicious activity and step in quickly, preventing loss, harm, damage and destruction to infrastructure and data 1.5.B.4.

Detect: AI does not replace the logs you will read in Units 3 to 5. It decides which ones a person reads first.

Exam traps

  • An answer saying AI recommendations (configurations, code fixes, detection rules) are put in place with no human review is almost always wrong.
  • Raising alerts or taking a set corrective action automatically is a normal use of AI [1.5.B].
  • Topic 1.4 is AI used by adversaries; topic 1.5 is AI used by defenders.

Simulator and checkpoint for 1.5 →

Notes done

Now practice the whole unit

Mixed questions from every topic work better for memory than one topic at a time. Recall the lists first, then answer exam-style questions and a free response.

Go to the Unit 1 review →

Was this page helpful?

Please do not include personal details. To get a reply, email [email protected].

Course mapYou are here: Unit 1
↑ Top

Enlarged view of the selected figure