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DoD Cyber Test Cheat Sheet

Practice QuestionsStudy Guide

Logical Reasoning

25%of exam

Sequences + PatternsDeductive LogicConditional + BooleanContrapositive vs Converse

Problem Solving

25%of exam

Troubleshooting MethodDebugging + BackupsRoot causeInside-out isolation

Networking Basics

20%of exam

IP AddressingProtocols + PortsOSI + TopologiesTCP vs UDP

Hardware + Software

15%of exam

Hardware ComponentsOS + File SystemsBinary + HexCPU vs RAM

Cybersecurity Fundamentals

15%of exam

CIA + EncryptionAuth + Access ControlThreats + AttacksCAC + MFA

Quick Facts

Exam
DoD Cyber Test
Questions
~40 MCQ
Time
15-20 min
Pass
Pass/fail, MOS minimum
Fee
Free at MEPS
Format
Computer-based
Taken with
ASVAB at MEPS

Arithmetic vs Geometric

Arithmetic

  • Add constant
  • 2 5 8 11
  • Linear growth

Geometric

  • Multiply ratio
  • 2 6 18 54
  • Exponential growth

Add vs multiply

Sequence Type Picker

  1. Constant difference→Arithmetic(Add)
  2. Constant ratio→Geometric(Multiply)
  3. Sum of previous two→Fibonacci
  4. Two alternating rules→Alternating series
  5. Letters plus numbers→Dual pattern
  6. Grid positions shift→Rotation

Sequences + Patterns

Arithmetic
Add constant difference
Geometric
Multiply constant ratio
Fibonacci
Sum of previous two
Alternating
Two interleaved rules
Letter-number
Parallel letter and digit
Matrix shift
Rotating grid positions

Contrapositive vs Converse

Contrapositive

  • Flip and negate
  • Not Q, not P
  • Always valid

Converse

  • Just reverse
  • Q then P
  • Not guaranteed

Valid vs invalid

Deductive Logic

Modus ponens
P true, so Q
Modus tollens
Not Q, not P
Contrapositive
Flip and negate; valid
Converse
Reverse; not guaranteed
Syllogism
Chain two premises
Deduction
Certain, not probable

Conditional + Boolean

If-then
Condition triggers action
Nested IF
Inner runs if outer passes
AND
All clauses must pass
OR
One clause enough
NOT
Inverts the value
Truth table
Maps all outcomes

Differential vs Incremental

Differential

  • Since last full
  • Restore: full plus one
  • Grows over time

Incremental

  • Since last backup
  • Restore: full plus all
  • Smaller each run

One vs chain

Troubleshooting Picker

  1. Browser fails, IM works→DNS issue
  2. Address is 169.254→DHCP failure
  3. USB prints, network fails→Network path
  4. Crash at fixed time→Scheduled task
  5. One stage dominates time→Bottleneck
  6. Loop count is wrong→Off-by-one
  7. Isolate a failure→Test inside-out

Troubleshooting Method

Reproduce
Confirm the failure first
Isolate
Narrow to one cause
Inside-out
Localhost, router, then internet
Divide + conquer
Halve the search space
Root cause
Fix source, not symptom
Bottleneck
Slowest stage dominates time

Debugging + Backups

Off-by-one
Boundary count wrong
Print debugging
Log values per stage
Syntax error
Code will not run
Logic error
Runs but wrong output
Full backup
Everything, every time
Differential
Changes since last full
Incremental
Changes since last backup

OSI 7 Layers

Please Do Not Throw Sausage Pizza Away

PhysicalData LinkNetworkTransportSessionPresentationApplication

TCP vs UDP

TCP

  • Connection-oriented
  • Handshake plus ACK
  • Web, email

UDP

  • Connectionless
  • No guarantees
  • Streaming, VoIP

Reliable vs fast

Protocol + Port Picker

  1. Need reliable delivery→TCP
  2. Need low latency→UDP
  3. Load a web page→HTTP(80)
  4. Secure web traffic→HTTPS(443)
  5. Remote command line→SSH(22)
  6. Transfer files→FTP(21)
  7. Resolve a name→DNS(53)

IP Addressing

Class A
First octet 1-126
Class B
First octet 128-191
Class C
First octet 192-223
Private range
10, 172.16, 192.168
255.255.255.0
254 usable hosts/24
APIPA 169.254
No DHCP reached
NAT
Private to public IP
IPv6
128-bit colon hex

Well-Known Ports

80 HTTP, 443 HTTPS, 22 SSH, 21 FTP

80: HTTP443: HTTPS22: SSH21: FTP53: DNS25: SMTP

Protocols + Ports

TCP
Reliable, connection-oriented
UDP
Fast, connectionless
HTTP
Web pages80
HTTPS
Encrypted web443
SSH
Secure remote shell22
FTP
File transfer control21
DNS
Name to IP53
DHCP
Assigns IP addresses67
SMTP
Sends email25

IPv4 Class Ranges

A 1-126, B 128-191, C 192-223

A: 1-126B: 128-191C: 192-223127: loopback

OSI + Topologies

Layer 1 Physical
Cables and signals
Layer 2 Data Link
MAC, switches, frames
Layer 3 Network
IP and routers
Layer 4 Transport
TCP, UDP, ports
Layer 7 Application
User-facing protocols
Star
Central switch, single point
Mesh
Every node interconnected
Bus
Shared backbone line

RAM vs Storage

RAM

  • Volatile
  • Loses data off
  • Active working data

Storage

  • Non-volatile
  • Keeps data off
  • Long-term files

Temporary vs permanent

Hardware Components

CPU
Executes instructions
RAM
Volatile working memory
SSD
Flash, no moving parts
HDD
Spinning magnetic platters
GPU
Parallel calculations
UEFI / BIOS
Initializes hardware, boots OS
Motherboard
Connects all components
Cache
Fast CPU memory

OS + File Systems

Kernel
Hardware-software bridge
Process
Running program instance
File permissions
Read, write, execute
Virtual machine
Emulated OS via hypervisor
Linux
Dominant server OS
Virtual memory
Disk swap when full
Directory
Folder holding files

Binary + Hex

Bit
Single binary digit
Byte
8 bits, 256 values
Nibble
4 bits, one hex digit
Binary
Base 2
Hex
Base 16
FF
255, one full byte
2^8
256 combinations
Decimal 13
Binary 1101

CIA Triad

Confidentiality, Integrity, Availability

C: keep secretI: prevent tamperingA: keep online

Symmetric vs Asymmetric

Symmetric

  • One shared key
  • AES
  • Fast bulk

Asymmetric

  • Public plus private
  • RSA
  • Solves key exchange

Shared vs key pair

Security Goal Picker

  1. Keep data secret→Confidentiality
  2. Prevent tampering→Integrity
  3. Keep it online→Availability
  4. Verify identity→Authentication
  5. Limit permissions→Least privilege
  6. Classified labels→MAC

CIA + Encryption

CIA triad
Confidentiality, integrity, availability
Confidentiality
Keep data secret
Integrity
Prevent tampering
Availability
Keep systems reachable
Symmetric
One shared keyAES
Asymmetric
Public plus privateRSA
Hashing
One-way fingerprint
TLS
Encrypts data in transit

MFA Factor Types

Know, Have, Are

Know: passwordHave: CAC tokenAre: biometric

Trojan vs Worm

Trojan

  • Disguised software
  • Needs user action
  • No self-replication

Worm

  • Self-replicates
  • No user needed
  • Spreads over network

Tricked vs automatic

Auth + Access Control

Authentication
Prove who you are
Authorization
What you may do
MFA
Two different factor types
CAC
Smart card you have
MAC
Clearance labels enforced
RBAC
Access by job role
DAC
Owner sets permissions
Least privilege
Minimum access needed

Threats + Attacks

Virus
Needs host file
Worm
Self-replicates over network
Trojan
Disguised, needs user action
Ransomware
Encrypts, demands payment
Phishing
Fake message steals data
DoS
Floods to deny service
Zero-day
No patch exists yet
Social engineering
Manipulates people, not code

Common Traps

Arithmetic vs Geometric

Arithmetic adds constant ≠ Geometric multiplies ratio

Contrapositive vs Converse

Contrapositive always valid ≠ Converse not guaranteed

Bit vs Byte

Bit is one digit ≠ Byte is eight bits

CPU vs RAM

CPU executes instructions ≠ RAM only stores

TCP vs UDP

TCP reliable, slower ≠ UDP fast, no guarantee

DoS vs Phishing

DoS hits availability ≠ Phishing hits confidentiality

Padlock is not trust

Padlock means encrypted ≠ Site may be malicious

Last Minute

  1. 1.About 40 questions, 20 minutes
  2. 2.Logic and problem-solving weigh most
  3. 3.Arithmetic adds; geometric multiplies
  4. 4.Contrapositive valid; converse is not
  5. 5.TCP reliable; UDP fast
  6. 6.80 HTTP, 443 HTTPS, 22 SSH
  7. 7.Class A starts at 1
  8. 8.255.255.255.0 gives 254 hosts
  9. 9.CPU executes; RAM stores
  10. 10.CIA: confidentiality, integrity, availability
  11. 11.MFA mixes different factor types
  12. 12.AES symmetric; RSA asymmetric
  13. 13.Read fake domains right to left

DoD Cyber Test

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