Week 1: Introduction to Ethical Hacking & Networking
Ethical Hacking Full Course Revision: All 12 Weeks in One Session
Core Concepts
- Ethical Hacking: Legal, authorized identification of system/network vulnerabilities
- Three Penetration Testing Approaches:
- White Box Testing: Full/detailed information about the target
- Black Box Testing: Little or no prior information
- Gray Box Testing: Partial information
Switching Techniques
- Packet Switching: Divides data into packets, suitable for bursty traffic (bandwidth used as needed)
TCP/IP vs. OSI Model
- TCP/IP Model: 4 layers (Application, Transport, Internet, Network)
- OSI Model: 7 layers
Key Differences
| Feature | TCP | UDP | |---------|-----|-----| | Connection | Connection-oriented (reliable, ordered delivery) | Connectionless (no guarantee) | | Handshake | 3-way handshake (SYN, SYN-ACK, ACK) | None |
- IP (Internet Protocol): Logical addressing, routing packets between networks; connectionless, no delivery guarantee
- TTL (Time to Live): Decremented by routers; packet discarded at 0 to prevent infinite looping
Layer Assignments
- MAC Address: Data Link layer
- IP Address: Internet layer (logical addressing)
- Port Numbers: Transport layer (identify services/endpoints)
Important Numerical Values
| Item | Value | |------|-------| | IP v4 Address | 32 bits | | Port Number | 16 bits | | IP Header Checksum | 16 bits | | IP v4 Header Length (IHL) field | 4 bits | | IP Header Length formula | IHL × 4 bytes | | Maximum IHL | 15 (giving max header 60 bytes) |
Previous Assignment Questions
- Objective of ethical hacking: Legally identify system vulnerabilities
- Full target information: White box testing
- Bursty traffic uses: Packet switching
- Connectionless, no reliability: UDP
- Prevents infinite looping: TTL (Time to Live)
- Max header length: 15 × 4 = 60 bytes
- Header checksum size: 16 bits
Week 2: IP Addressing, Fragmentation & Subnetting
IP Fragmentation
- Purpose: Divide packets when exiting outgoing networks due to varying MTU (Maximum Transmission Unit)
- Three Fragmentation Fields: Identification, Flags, Fragment Offset
- Fragment Offset Formula: Position in units of 8 bytes
- Example: Offset 100 means byte position = 100 × 8 = 800 bytes
Fragmentation Flags
- D (Don't Fragment): D=1 means fragmentation prohibited
- M (More Fragments): M=1 means more fragments follow; M=0 indicates last fragment
IP Header Length Calculation
- Formula: IHL × 4 bytes (IHL in 32-bit words)
- Maximum IHL = 15 → Maximum header = 60 bytes
- Data Bytes = Total packet size – Header size
- Example: 2000 – 60 = 1940 bytes
IPv4 Address Classes
| Class | Range (First Octet) | Type | |-------|--------------------|------| | A | 1 – 126 | Unicast | | B | 128 – 191 | Unicast | | C | 192 – 223 | Unicast | | D | 224 – 239 | Multicast | | E | 240 – 255 | Reserved/Experimental |
Private IP Addresses
- 10.0.0.0/8
- 172.16.0.0/12 (range 172.16 – 172.31)
- 192.168.0.0/16
Subnetting Formulas
- Total addresses: 2^(32-n)
- Usable hosts: 2^h – 2 (h = number of host bits)
- VLSM (Variable Length Subnet Mask): Different subnets with different mask lengths
- CIDR (Classless Interdomain Routing): Prefix notation (e.g., /24)
TCP 3-Way Handshake
- SYN segment (SYN=1, ACK=0): Initial connection request
- SYN-ACK segment
- ACK segment
UDP Header
- Size: 8 bytes
- Fields: Source port, Destination port, Length, Checksum
Example Questions
- Fragmentation needed due to varying MTU
- D=0, M=1, offset=0 → packet fragmented, first fragment
- Class identification: 128 → Class B, 192 → Class C
- Private address check: 172.32 not private (range ends at 172.31)
Week 3: Routing & IPv6
Routing Types
- Static Routing: Manually configured, unchanged
- Dynamic Routing: Automatic route updates via protocols
Direct vs. Indirect Delivery
- Direct: Destination on same physical network
- Indirect: Destination on different network (uses default route)
Routing Table Flags
| Flag | Meaning | |------|---------| | U | Route is up | | G | Gateway used | | H | Host-specific route | | D | Dynamically created | | M | Dynamically modified |
Routing Protocols
| Protocol | Type | Algorithm | Key Feature | |----------|------|-----------|-------------| | RIP | Interior (IGP) | Distance vector | Uses hop count (max 15); drawback: count-to-infinity | | OSPF | Interior (IGP) | Link state | Least cost routing | | BGP | Exterior (EGP) | Path vector | Between AS; uses TCP port 179 |
IPv6
- Address size: 128 bits (IPv4: 32 bits)
- Header size: 40 bytes (fixed)
- No traditional classes (no A, B, C)
- Transition methods: Dual stack, tunneling, translation
Previous Questions
- Static routing: manually configured entry
- Count-to-infinity problem occurs in RIP
- Inter-AS routing uses BGP
Week 4: Visualization & Reconnaissance
Virtualization
- Hypervisor/VMM: Manages VMs, allocates resources
Reconnaissance Types
| Type | Method | Examples | Risk | |------|--------|----------|------| | Passive | Indirect info gathering (no direct probing) | Whois, Netcraft, Wayback Machine, search engine operators | Low detection | | Active | Direct communication with target | Nmap scanning | Higher detection risk |
Key Tools
- Whois: Domain registration information
- Netcraft: Website/hosting information
- Wayback Machine: Historical website snapshots
Google Search Operators
"exact phrase"- exact matchsite:domain.com- restrict to domainfiletype:pdf- specific file type
Nmap
- Functions: Host discovery, port scanning, service/version detection, OS detection
- ICMP Sweep: Type 8 (Echo Request), Type 0 (Echo Reply)
- -Pn: Skip host discovery, treat all hosts as online
- -sn: Host discovery only (no port scan)
Previous Questions
- Hypervisor allows multiple VMs on one host
- Passive = indirect, no detection risk
- Active = direct collection
- ICMP type 8 = request, type 0 = reply
- Nmap can scan 1000 ports by default
Week 5: Vulnerability Scanning & System Hacking
Port Scanning vs. Vulnerability Scanning
| Scanning Type | Purpose | |---------------|---------| | Port scanning | Identify open/closed/filtered ports | | Vulnerability scanning | Identify security weaknesses in systems/networks/apps |
Tools & Concepts
- NSE (Nmap Scripting Engine): Automates checks via scripts
--script default: runs default scripts
- Nessus: Remote security scanner, generates scan reports
- Password Cracking: Attempts to recover/guess passwords
- Privilege Escalation:
- Vertical: Gain higher-level permissions
- Horizontal: Access same-level but different user accounts
Malware Types
| Type | Description | |------|-------------| | Virus | Attaches to host/program | | Worm | Self-propagates independently | | Trojan | Disguises as legitimate software | | Ransomware | Holds data/access for ransom |
- Principle of Least Privilege: Grant only required permissions
Previous Questions
- NSE script checking for slow loris DoS:
slowloris-check - ARP: maps IP to MAC address
Week 6: Security Attacks & Cryptography
Security Attack Categories
| Attack Type | Affected Security Goal | Example | |-------------|------------------------|---------| | Interruption | Availability | Denial of Service (DoS) | | Interception | Confidentiality | Eavesdropping | | Modification | Integrity | Data tampering | | Fabrication | Authenticity | Inserting fake messages |
Symmetric vs. Asymmetric Cryptography
| Feature | Symmetric | Asymmetric | |---------|-----------|------------| | Key | Same secret key for encryption & decryption | Public/private key pair (different keys) | | Speed | Faster | Slower | | Suitable for | Large data amounts | Small data/key exchange | | Examples | DES, Triple DES, AES | RSA, Diffie-Hellman |
Key Algorithms
- AES (Advanced Encryption Standard):
- Symmetric block cipher
- Fixed block size: 128 bits
- Supported key lengths: 128, 192, 256 bits
- RSA: Asymmetric, based on prime factorization problem
Key Number Formulas
| System | Formula | Example (n=100 parties) | |--------|---------|-------------------------| | Symmetric (private key) | n × (n – 1) / 2 | 100 × 99 / 2 = 4950 | | Asymmetric (public key) | 2 × n | 2 × 100 = 200 |
Substitution (Shift) Cipher
- Formula: C = (P + K) mod 26
- P = plaintext letter position (0–25)
- K = key (shift value)
- C = ciphertext letter position
Previous Questions
- 100 parties using RSA: 200 distinct keys
- DoS attack = interruption (affects availability)
- AES key lengths: 128, 192, 256
Week 7: Hash Functions, Digital Signatures, SSL & IPsec
Hash Functions
- Properties: Variable-length input → fixed-length output; same input → same hash; different input could produce same hash (collision)
- Types:
- Unkeyed Hash (MDC): For integrity only
- Keyed Hash (MAC): For integrity + authentication
Common Hash Algorithms
| Algorithm | Output Size (bits) | Block Size (bits) | |-----------|-------------------|-------------------| | MD5 | 128 | 512 | | SHA-1 | 160 | 512 | | SHA-256 | 256 | 512 | | SHA-512 | 512 | 1024 |
SSL & IPsec
- SSL: Provides authentication, integrity, privacy
- IPsec:
- Transport mode: Protects payload only
- Tunnel mode: Protects entire original packet
Previous Questions
- Two different messages producing same hash: collision (can be true for any hash function)
- Unkeyed hash function = MDC (Modification Detection Code)
- SHA-512 block size = 1024 bits
- Digital signature provides non-repudiation
Week 8: Steganography, Biometrics & DoS
Steganography vs. Cryptography
| Feature | Cryptography | Steganography | |---------|--------------|---------------| | Hides | Meaning of message | Existence of message | | Medium | Any (encrypted text) | Image, audio, video, etc. |
LSB (Least Significant Bit) Steganography
- RGB image: Each pixel has 3 color channels (Red, Green, Blue)
- Capacity formula (in bytes):
(Width × Height × Number of color channels × Bits hidden per channel) / 8 - Example: 200 × 150 RGB image, 1 bit per channel → capacity = (200 × 150 × 3 × 1) / 8 = 11,250 bytes
Biometrics
| Type | Examples | |------|----------| | Physiological | Fingerprints, iris patterns, retina patterns | | Behavioral | Signature dynamics, keystroke patterns |
Denial of Service (DoS) Attacks
- Goal: Prevent legitimate users from accessing a service (affects availability)
- Examples: Smurf attack, Ping of Death (oversized IP packets)
- DDoS: Distributed DoS from multiple sources
DNS (Domain Name System)
- Maps human-readable domain names to IP addresses
Previous Questions
- Capacity calculation for LSB: (200 × 150 × 3 × 1) / 8 = 11,250 bytes
- DoS example: Ping of Death, Smurf attack
Week 9: Sniffing, Social Engineering & Network Attacks
Packet Sniffing
- Capturing and examining network packets
- Wireshark: Packet capture and network analysis tool
- Displays packet details, protocol info, statistics
- Does not perform SQL injection or manipulate live traffic
Social Engineering
- Manipulating people to reveal confidential info or perform compromising actions
- Reverse Social Engineering: Attacker poses as authority, victim approaches them for help
Network-Level Attacks
- SYN Flood: Exploits TCP 3-way handshake
- Slowloris: DoS attack that keeps HTTP connections open by sending partial requests without completing them
- Botnet: Network of compromised devices controlled by attacker
Previous Questions
- Social engineering manipulates humans
- Reverse social engineering: victim approaches attacker
- SYN flooding, slowloris, botnet related
Week 10: Hardware Security
Hardware Attacks
- Physical probing: Accessing internal chip signals using physical techniques (invasive)
- Reverse engineering: Examining internal structure and functionality of a chip (invasive)
Side-Channel Attacks
- Infer information from physical characteristics during computation (non-invasive)
- Types: Timing analysis, Power analysis (SPA, DPA), Electromagnetic (EM) analysis
- SPA (Simple Power Analysis): Examines power traces directly
- DPA (Differential Power Analysis): Uses multiple measurements + statistical analysis
Hardware Trojans
- Malicious modification inserted into chip design or circuitry
PUF (Physical Unclonable Function)
- Provides device-unique authentication based on inherent physical variations
Previous Questions
- Invasive attacks: Physical probing, Reverse engineering
- PUF: Physical Unclonable Function
- Side-channel attacks: Timing, power, EM
Week 11: Metasploit, SQL Injection & XSS
Important Note
- Security testing only on systems you have authorization for
Metasploit Framework
- Exploit: Module to take advantage of a vulnerability
- Encoder: Encodes payloads to evade detection
- Payload: Code that runs on target after exploitation
SQL Injection (SQLMap)
- SQLMap: Automated tool for detecting/exploiting SQL injection
- Extract credentials:
--users,--passwords,--current-user - Database enumeration:
--dbs,--tables,--columns
XSS (Cross-Site Scripting)
| Type | Description | |------|-------------| | Stored XSS | Malicious script stored on server (e.g., in database) | | Reflected XSS | Script reflected off server (e.g., in search results) | | DOM-based XSS | Vulnerability in client-side script |
Previous Questions
- Exploit module: takes advantage of vulnerability
- SQLMap credential extraction:
--users,--passwords,--current-user
Week 12: Nmap Options & Wireshark Recap
Key Nmap Options
| Option | Purpose |
|--------|---------|
| -PE | ICMP Echo discovery (type 8 request) |
| -sn | Host discovery only (no port scan) |
| -Pn | Skip host discovery, treat all hosts as online |
| -sT | TCP Connect scan (full connect scan) |
| -sV | Service/version detection |
| -O | OS detection |
| (default) | Scan 1000 most common ports |
Critical Recall Points
-PEused for ICMP echo sweep- Type 0 echo reply = host is live
- -Pn treats all hosts as online (no discovery)
- Default Nmap scan = 1000 ports
Final Exam Quick Reference
Key Formulas to Remember
- IP header length = IHL × 4 bytes (max 60 bytes)
- Fragment offset (byte position) = offset value × 8
- Data bytes = Total packet size – Header size
- Subnet usable hosts = 2^h – 2
- Symmetric key count = n × (n – 1) / 2
- Asymmetric key count = 2 × n
- Shift cipher = (P + K) mod 26
- LSB capacity (bytes) = (W × H × channels × bits per channel) / 8
Must-Know Identifications
- Connectionless protocol: UDP
- Connection-oriented protocol: TCP
- Routing using hop count: RIP
- Link-state routing: OSPF
- Inter-AS routing: BGP (port 179)
- Hash for integrity only (unkeyed): MDC
- Steganography vs. Cryptography: Hides existence vs. meaning
- DoS attack examples: Smurf, Ping of Death
- Invasive hardware attacks: Physical probing, Reverse engineering
- Side-channel attacks: Timing, Power (SPA/DPA), EM
For a broader perspective on ethical hacking principles and career paths, see the Comprehensive Guide to Ethical Hacking: From Basics to Advanced Concepts. If you are a student preparing for Class 11th Computer Science, the Class 11th Computer Science Complete Revision - Python, Logic Gates & Cybersecurity summary can help you review related foundational topics. For a structured learning path, beginners might start with the 30-Day Ethical Hacking Challenge: Day 1 - Introduction to Ethical Hacking. For an overall review of the cybersecurity field, the Complete Cybersecurity Full Course: Threats, Tools & Career Guide is a valuable resource.
Hello everyone, welcome back. In this video, we are going to revise all 12 weeks of ethical hacking in one session.
So this is an exam oriented revision class. We'll focus on important concepts, core formulas, technical terms
and previous assignment questions. So don't try to memorize each every sentence. Concentrate on understanding
the concepts remembering important numerical values and distinguishing between similar terms. Okay, let's start
with week one introduction to ethical hacking and uh networking. So ethical hacking is a
legal and authorized identification of vulnerabilities in systems and networks. So ethical hackers work with permission
identify the weakness and report them so that they can be corrected.
So first remember three penetration testing approaches. White box Testing means the tester has full or
detailed information about the target. This one blackbox testing means the tester has
little or no prayer information and the gray box means partial. So these three terms are important because exam
questions often ask you to identify the correct testing methodology from this description.
So next the security testing where evaluates whether system and networks have weakness and whether their security
controls are working correctly. Now let's look at the switching uh switching techniques. So packet
switching divides data into packets and shares the network resources. It is suitable for
busted traffic. It is suitable for busty traffic because bandwidth is used as needed. So next is
the TCP IP model. It is commonly represented using four layers application, transport, internet and
network. So each layer a different responsibility in network communication. So next will be
the next the TCP IP model it is commonly represented using the four layers. So the O OSI model has seven layers. Now
remember the difference between the TCP and IP. TCP is a connection oriented and provides reliable order delivery.
UDP is connectionless and does not guarantee delivery.
The internet protocol or IP provides logical addressing and routes packets between the networks.
So it is it is also connectionless. IP itself does not guarantee the packet
delivery. TTL stands for time to live. Route routers decrease the TTL value as the
packet travels through the network. So when it reaches zero the packet is discarded
the packet is discarded. This prevent a packet from circulating in infinity infinity looping.
The MAC address is associated with the data link layer and IP address provides logical addressing at the
internet layer. So port number identify services and points at the transport layer. So these are the different value
numerical value. Try to memorize it. The O OSI model will be having seven layers. TCP IP means four layers. IP v4 address
is 32 bits. Port number 16 bits. IP header check sum 16 bits. IP V4 ln four bits IP header length ln
into four bytes these questions from this you'll be getting the questions for your final exam also maximum value is 15
so maximum IP header length will be 15 into 4 I will be having 60 bytes so the formula for IP header length
header length is equal to ln into four bytes. So these are the exam quick revision
things. Ethical hacking white box, black box, gray box and packet switching your layers
TCP difference between a TCP and UDP. The the main formula will be ln into 4. The length check sum will be it will be
16 bits. So port number where we'll be having is in transport layer. The MAC address will be done in the data link
layer. We'll see some previous assignment questions. So what is the main objective of ethical
hacking? We'll be knowing legal identify the system vulnerabilities. So which of the following
types of penetration testing? White box, black box and gray box. In the option only white box and black box
are given. more busty traffic. We already seen that it is a packet
switching. So it's a connectionless and does not provide reliability. It
will be UDP and TCP will be connection oriented. So which IP header prevents infinite
looping of packets? It is time to leave TTL. These are the other question. The
maximum value 15 and the bytes will be 15 into 4 I will be getting 60 bytes. So
header check sum it is 16 bits. So weak one white box means detailed information.
Black box means little or no information. Gray box means partial information. TCP
reliable. UDP connectionless. IP handles addressing and routing. TTL prevents infinite packet pack packet
looping and ln length will be 15. Header length will be 15. So remember these terms. Now we'll move on to week two. So
week two is about IP addressing fragmentation and uh subnetting. The first three three to four units
we'll be having the basic concepts of computer networks. So here more formulas will be coming. IP fragmentation divides
a packet into smaller fragments when it exits the out outgoing networks. MTU stands for maximum transmission
unit. The three important fragmentation fields are this one identification,
flax and fragment offset. The fragment of offset
provides the specifies a fragment position in unit of 8 bytes. So this is the formula.
For example, if the fragment offset is 1,000 means 100 means the bite position is 800
bytes. 100 into 8 you'll be having 8 800. So next is the fragmentation flags. D don't fragment. D is equal to 1 means
fragmentation is prohibited. M for more fragments. M is equal to 1 means more fragments follow. M is equal
to0 indicates the last fragment. And uh the IP header length we already seen this formula in the week one itself
ln into four bytes it will be mentioned in 32 bits words. So we can to convert into bytes we'll be
multiplying by four. So the maximum mental is 15 giving a maximum IP header length of 60 bytes.
Calculate the data bytes that is equal to total packet size total packet size minus the header size.
For example, if the packet size is 2,000 and the header size we are already seeing that 60 bytes. So the data size
will be 1 1940 bytes. So so the next thing is one of the
important concept IP v4 address classes. So we'll be dividing into class A, class B, class C, class D and class E.
Class A is from 1 to 126 the first octed used for the uniccast.
Class B 128 to 191 uniccast. Class C 192 to 223 it is also uniccast. Class D 224 to 22 multiccast and class D
is for reserved for and for experimental purpose. And the next is the private address private IP address.
So used inside the private networks and are not globally routed as IPv4 10.0.0.0/8
172.16.0.0/12 and 192.168.0.0/16. 0/16.
So be careful 172.13 sorry 172.32 is not a private. So the private ranges within the 172 block
extend from 1726 to 17231. And the next one is the subnetting
divides the total network into smaller logical networks by using the bits from the position of an
address. So it helps organize the address allocation and separate network segments
segmenting. Total address is 2 power 232 32 - n and uh usable host will be 2^ h -2
where h is the number of host bits the formula is as special case uh exception so
apply according to the coing and the next one is vm and c variable length subnet masking
different subnets to use the different mask length and C classless interdomain routing prefix notation such as this /
24. So TCP I'll be having a three-way hand and
shake synchronization synchronization acknowledgement and the last one we'll
be receiving the acknowledgement if LCB segment with synchronization is equal to one and acknowledgement is
equal to zero it indicates the initial connection request. Then next one UDP header eight bytes and
contain four bits source port, destination port, length and the check sum.
Remember these things are uh these are the important concepts that that is a exam quick revision for unit
3. The main things are this one and uh this has we are already
discussed this class B class C your private address ranges initial TCP connection request
UDP and if D is equal to0 don't fragment M is equal to0 more fragments we'll discuss some previous questions
why do we need fragmentation to due to the varying MTU across the networks
and these questions will be having multiple answer. D flag is set zero and M flag set is one
offset is zero. So which of the following is true? The packet has been fragmented and this
and it is the first fragment this also we had already discussed 2,00 and this lener is 15 so bytes will
be 15 into 4 I'll be getting 60 bytes 2,000 - 60 the answer will be 1 9
4 0 in the choice they are given as a range. So this is this will be the range and uh
this example will be surely be asked for your final exam. They will be giving a class address
ranges and which class they belong to. This 128 means class B and this 192 193 also will be belonging to class D.
Private address as we discussed early. This is one of the private address but here they are given as
172.32. It must be 16 to 31. So this is only this is correct.
The correct answer is option C. Synchronization is equal to 1 and acknowledgement is equal to zero.
Initial connection request UDP header we'll be knowing eight bytes. in the next one.
So if you they are giving the question like did this for subnetting. So we have to do the and operation
bitwise and convert this 192 into binary form. For 255 I'll be having eight ones. 1 one one
one. So if you are multiplying this binary convertible value into all one means 1
into 1 I'll be getting one. So the final answer will be for the two terms I'll be having 255 255. So this 192 168 will be
same and this 77 has to be converted into binary. Then you have to multiply it with the binary value of 232.
Any any value multiplied with zero I'll be getting zero. The answer will be this one.
So next is week four uh sorry week three routing and IP IP v6. The main concept is
routing determines how packets move from a source network to a destination network. Static routing,
manual configuration, manually configured routes. Dynamic routing, there is no automatic update. And
dynamic routing allows router to exchange information and update the routes automatically.
So direct versus indirect delivery. Direct delivery when a destination is reached over a
locally connected network same physical network and this one is for another network.
So default route this is the thing 0.0.0. So routing table flags I'll be using
these terms. U denotes route is up. G is oh no G means gateway. H is the post specific route,
dynamically created route, dynamically modified route and uh now the routing protocols
I'll be classifying as interior gateway protocols, exterior gateway protocols. Interior means within an autonomous
system. example your routing information protocol and OSPF open shortest path first then external gateway routing
protocol I'll be having BCP border gateway protocol routing between different autonomous system
different autonomous system so RIP one of the interior routing it uses distance sector routing and uses is the
outcome. So the main drawback is count to infinity problem or routing loop
problems. So it comes under interior plus distance vector plus up count
OPF open shortest path. It uses it is also interior routing. It uses link state. Link state.
So calculates the route with the least cost. Link state plus lease cost. Here it is
distance vector plus the up count and uh border gateway protocol routing between different autonomous systems.
So it uses that ECP port 179 that is interas inter means between different different
autonomous system. So interas plus TCP 179 and these are some BJP BGP messages. The last one is will be IP V6.
So V4 will be using 32-bit address while V6 will be using 128 bit addresses. It will not be it will not use the
traditional addressing class A, class B and class C. [snorts] Base header size is 40 bytes
and these are the transition. This is a quick revision. So what you We have seen direct delivery indirect
delivery default route RIP
the drawback is count to infinity problem and this one PGP inter enter inter means different
different autonomous system plus it uses that TCP port 179 IPv6 128 bits header is 40 bytes
No, no traditional classes like class A, class B and class C. Transition you'll be having dual stack tunneling and
translation. So these are some previously asked uh assignment questions.
A routing table entry that is manually configured remains unchanged unless manually modified. dash is called the
routing table entry static and these are the other questions and this denotes a multiple
andable answer can be selected as we seen already count to infinity problem it occurs in RIP
different different autonomous system or interas we are will be using border gateway
protocol. So week four is about visualization reconc
uh visualization allows multiple virtual machines to run on one physical computer.
IPA super supervisor or also called as a virtual machine monitor manages the virtual machines and allocates
resources. There are two types of approaches. One is a pack passive and another one will
be active. Passive means gather information indirectly without
directly probing the target. Example include WHIS, Netcraft, the wayback machines and
search engine operators. Active involves direct communication with the target. So it can reveal more technical
information but it has a greater risk of detection. So these are the examples of passive
and Google search operator. So remember these tools whis provides domain registration
information. Domain registration information. Netcraft provides a website and hosting
related information. The wayback machine provides historical website snapshots.
Historical website snapshots. Now the search operators the quotation marks are used to search
for an exact face. The site this one site operator restricts results to a
particular website or a domain. Then file type operator searches for files of a specified type.
And the next one is a NMAP network delivery and scanning tool. It fuses include host dis discovery,
port scanning, service and uh version detection and operating system detection,
ICMP sweep. So ICMP type 8 echo request and type zero echo replay. And the next will
be the post discovery. So these are the main thing you have to remember
and these are some previous questions. So which of the following statement is true? A hypervisor allows
only one host to run multiple virtual machines by sharing the resources. Passive. Passive as I told information
about the target is collected indirectly and there is no chance of deduction. Active means it will be collected
directly. And these are the other questions. Sweep
is used to detect the live host. And this one-ph
tells nm a to skip the port scanning and perform only host discovery.
So focus on passive versus active difference. the purpose of uh WHIS and the wayback machines, Google search
operators and MP request versus reply. So passive means indirect active means
direct. WHIS provides registration information. Way back provides historical snapshots.
ICMP type 8 is request and type zero is replay. So how many ports does uh NMAP can scan?
So it it will be th00and ports and coming to the week five vulnerability scanning and system
hacking. First distinguish port scanning from vulnerability scanning. Port scanning
identifies open, closed or filtered ports on a target system.
It is not same as the full vulnerability assessment. Then coming to the vulnerability
scanning searches for security weakness in system networks and applications that is identify the
weakness in the systems. So these are some tools and NMAP scripting engine or NS extends
NMAP through scripts that automate different checks. The script script default opens the
default NSC scripts and these are the other concepts. Excess is a remote security scanning
tool that examines computer and networks for vulnerabilities and generates scan reports. Password cracking is there.
Attempts to recover or guess passwords. Privilege escalation occurs when a user gains permission
beyond the current access level. Two types vertical privilege escalation
horizontal privilege escalation. So the last one will be malware. It's a malicious software intended to perform
unwanted or harmful actions. Know the difference between these terms?
Surely questions will be asked on this. This is a quick revisions for the
week five. Virus attaches to host or a program. W means can self-propagate
deep inside it. Targen distinguishes itself as a legitimate software and this ransomware holds data or access
for a ransom. Least privilege grant only the permission required. So these are some questions asked the
previous assignments. So which of the following NMBB scripts checks for vulnerability to a slow
lowrisisk do attack? It will be slow check. Uh this is the last one address
resolution protocol. It maps IP address to a MAC address in a local network. Next is about V six.
Main thing many formulas we'll be using here security attacks and cryptography security attacks security attack
categories cryptographics algorithm and key formulas first remember the four classic security attack categories
interruption affects availability. So this is the attack type and this is
the what type of security it is. Example do denial of service and in interception it it affects the confidentiality
unauthorized reading of data modification it affects the integrity and fabrication it affects the
authenticity inserting fake messages or data Just try to memorize this pass.
Interruption means availability, interception, confidentiality. Okay. The next one is symmetric key cryptography
uses the same secret key. Symmetric. So same secret key for encryption and decryption
faster than the asymmetric cryptography suitable for encrypting large amounts of data. Remember these things. Examples
are dees, triple dees and aes. Whereas a symmetric key uses public private key pair.
Same key will same key will not be used. The keys are different roles in encryption and decryption depending upon
the protocol. Examples are your RSA and your DEF element. DS and AS
DS DS and triple DES and AS also will be having advanced encryption standard. A
is a symmetric block cipher with a fixed 128 bit block size length are 120.
This will be surely will be asked in the exam. It support it supported key length. It
not only supported 128, it supports 128, 192 and 252. RSA asymmetric key algorithm
prime factorization problem the main thing the concept what we'll be using in RSC for the key counts the end user each
need the distinct shared symmetry key for each every pair the number of keys will be given by n into n minus one by 2
the diff element and key exchange. So this one what I told number of keys is equal to n into n
minus one by 2 public key system number of case is 2 n. If the number of keys depends on
cryptographic system the formula is this one number of n into n minus one by 2. For public key system number of keys is
equal to 2 into n. Then the we'll be having a substitution cipher each plain text letter which replaced
with another letter corresponding to a mapping or a key. So this is the formula. Surely problems will be asked
in this by using this formula. just you have to convert the cipher plain text into
cipher text by using the you have to add the key and you have to take mod 26.
So these are the important concepts what you have seen. A quick revision.
Memorize these four terms. Symmetric key same as symmetric different. And uh memorize
this block size also. DS 56 AES 128. AES can also support 128, 192 and 256. symmetric key n into n - 1 by 2 private
public key 2 n shift cipher I'll be using p + k mod 26 so these are the
previous previously asked questions 100 parties want to exchange messages securely using public cryptographic RSA
the number of distinct key will be 200 and this one we also we have seen just memorize it
attack the do it is a interruption here you have to apply the formula then you have to calculate it
a as I It not only supports 128, it also
supports 192 and 256. So week seven is about ash function, digital signature, SSL and IP security.
A cryptographic ash function takes input of a variable length and produces a fixed length output.
The same input produces the same ash. Different input can produce same ash value. This is called a collision
collision. So in this we'll be having an key dash or modified modification detection code
MDC message authentication code MAC and many ash algorithms. So these are the examples SHA 512.
So ash mapping many to one same input means same as different
messages plus same as is called collision. So un key dash I'll be using the term called as MDC for integrity
MD5 means it is a 128 bit ash sa memorize these four parts definitely you'll be getting a questions
in this sa 1 means 160 bit sa 256 256 bit dash 512 5 bit output 512 block size is,024
SSL authentication integrity and privacy IP sector tunnel the entire original
packet protected. So these are some previously asked
questions. Two messages m1 and m2 are fed to as function never be true. So the second option will
be never be true. Unkey dash function as I told MDC is for integrating
SHA 512 - bits blocks we have seen already,24 UN key function
MD5 and SHA 26 valid signature created by nonrepudiation.
So IP IP sector transport information with production. I'll be using the transport mode
and VK is about stemography biometrics and de denial of service. Stegnography
hides the existence of a message by embedding it inside another medium such as image, audio or video.
Encryption is different. Encryption hides the meaning of information while
stegnography attempts to hide the existence of information. know the difference between both encryption and
uh steography. So one technique is least significant bit signography or I'll be calling as
LSB. So in an RCB image each pixel has three colors
red, green and blue. If one bit is hidden in each channel three bits can be stored per pixel.
This is the capacity formula in bytes width height and uh number of colors
channels into hidden bits per channel divided by 8. Since they are asking in bytes we are dividing by 8.
Physiological biometrics include fingerprints, iris patterns and retina patterns. Biological biometrics includes
your signature signature dynamics keytop patterns are and these are the other terms. Iris and
retina recognization denial of service. Edo attacks attempts to prevent legitimate user from accessing a
service. It affects the availability. Smurf attack and ping of death attack. Distributed denial of service. domain
name system maps the human readable domain names to IP address. So these are the
terms you have to remember steography encryption difference between a stemography and encryption LSP plus J
JPEG I'll be going against lossy compression three colors per pixel this is an
example 200 into 150 RGB of death oversized IP packets. And these are some previously asked
questions 200 into 150 which is stored in 24 bits three colors. They're asking the LSB.
This one denial of service attack. Example of denial of service attack is
ring of death smurf attack. And coming to the week nine, sniffing, social engineering and network attacks.
Packet sniffing means capturing and examining network packets. It can be used for troubleshooting and security
analysis, but it can also be misused to capture sensitive information. Wireshock is a packet capture and network analysis
tool. It displays packet details and provides protocol information and statistics
and these are the other terms. So coming to the social engineering, social engineering manipulates people
into revealing confidential information are performing action that compromise security.
That is a social engineering. In reverse social engineering, the attacker prevents themsself as an
authority and supports person and the victim approaches them for
assistance. Synchronization flooding. We are already seen this three-way handshake
and remember this term slow loris. Loris is a do attack that keeps HTTP
connection opens by sending the partial request without completing them. Then botnet is there.
Wireshark mode and Wireshark does not perform SQL
injection or manipulate live traffic. social engineering and this is the river
social engineering flooding slow botnet.
So these are some more important concepts and these are some previously asked
questions. uh next week will be hardware security. So
hardware based attacks hardware attacks target the physical device chip or its implementation to
obtain the secret information and cause unintended behavior that is the hardware things. There are many terms are there.
Physical probing involves accessing the internal chip signal using physical techniques. Reverse engineering examines
the internal structure internal internal structure and functionality of a chip.
Now the next will be the side channel attacks. Side channel attacks infer information
from physical characteristics of a device while it performs computation rather than attacking the algorithm
directly. Then differential power analysis hardware
hardware proen is a done malicious modification inserted into a chip chip design or the circuitry
physical uncolonable functions and these are the properties. Please know about hardware attacks, physical
probing, side channel attack, EM analysis, PUF
and the squaring and the multiplication term. And this one is also important one.
And these are some previously asked questions. Which of the following attacks hardware
are invasive in nature? Physical probing and reverse engineering. Physical uncolleable function PF.
So week 10 physical probing is invasive side channel includes timing power and EM. SP examines power traces
directly. DPA uses multiple measurements and statistical analysis. PF supports device unique authentication.
Week 11 is about metasplit, metasloit, SQL map, SQL injection and XLS. The practical security testing must be
performed only on the system for which you have authentication. That is the these parts.
Metasloit is a framework for security testing. So remember the network variables.
Sorry, just uh recall this concepts. Encoder, SQL map, SQL injection.
The main parts will be this yellow last Our last DBS database names, tables
know this symbols and uh what is the concepts stored XSS
stored script reflected input and unsafe? And these are the previously asked
questions. Which of the following metasloit models is used to take advantage of a
vulnerability on same target that is exploit is used to remove target port
set rebound and these are the SQL map. Which of the following SQL map contains extract credential related information?
users, password and current user. So coming to the last week, week 12 focuses on NMAP options and wire
wireshock re capture. So NMAP is used for the network
discovery and scanning. These and all we are already discussed including host discovery, port scanning.
Performs ICMP echo discovery. This one and type zero echo replay.
Then - SN performs the host discovery without port scanning and PN option skips host
discovery and treats the specified host as online. iPhone ST performs TCP connection scan
which is designed as a offen scan. SP optional items service and version detection.
Remember these the terms or which purpose you are reaching which uh syntax or
which part. So which option is used for ICMP echos sweep? Just now you have seen it is P
type zero means host is live by default 1,000 NMP scans means 1,000. The same type of question has been
repeated in the previous week assignments also. So it open NMAP treats all host as online.
So in this unit the we have to remember all the syntax like this
everything will be questions will be from the syntax only. So these are the most important formulas
and must memorize things. The first one networking seven layers. TCP IP four layers. IPv4 32 32
bits. Port is 16 bits. Headder is ln into 4. Maximum is IP header is 60
bytes. Subnetting. And these are the formulas.
Addressing class A, class B, class C, private address and routing. The important term is RAIP, OSPF,
PGP and recurrence and scanning NMAP options cryptography you'll be
applying some formula symmetric key public key and ashing MD5 security properties is so in each unit
one one term is important. Few units we'll be applying the formula. Remaining term you we have to memorize it.
What is the objective of ethical hacking? To legally identify system vulnerabilities.
Then connection less mean. So I'll be going for UDP. Formula for IP V4 header length is LN *
4 bytes. Which routing uses OP count? I'll be going for RIP.
Then which routing protocol is a link state? I'll be going for OPF. So like that we'll be having many many
questions. So we have now revised the important concepts from all 12 weeks of ethical
hacking. My final advice is to revise in st three stages. First understand the core concepts. Second memorize the
formulas, numerical facts, tool names and command options. Third, practice the previous questions without looking at
the answer. Use the keep your uh so in this revision helped you like the video, subscribe to engineering study desk and
share it with your classmates who are preparing for the same examination. Thank you for watching. All the best for
your exam. Thank you.
The three approaches are White Box, Black Box, and Gray Box testing. White Box testing provides the tester with full knowledge of the target system's architecture and source code, like an internal audit. Black Box testing gives the tester little to no prior information, simulating an external attacker. Gray Box testing is a hybrid, offering partial knowledge, such as login credentials, to balance depth and realism.
For symmetric cryptography, which uses a single shared key per pair, the formula is n × (n – 1) / 2, resulting in 4,950 keys for 100 users. For asymmetric cryptography, each user has a public and private key pair, so you need 2 × n keys, which is 200 keys for 100 users. This highlights why asymmetric systems are more scalable for key management in large groups.
A port scan identifies which ports are open, closed, or filtered on a target, while a vulnerability scan goes further to detect specific security weaknesses like outdated software or misconfigurations. For host discovery only, without scanning ports, you should use the Nmap option -sn, which sends probes like ICMP echo requests to see if hosts are online.
Cryptography hides the meaning of a message, making it unreadable, while steganography hides the very existence of the message within another medium like an image. To calculate capacity in bytes for LSB steganography in an RGB image, use the formula: (Width × Height × 3 color channels × bits per channel) / 8. For example, a 200×150 image with 1 bit per channel can hide 11,250 bytes.
The three transition methods are dual stack (running both protocols simultaneously), tunneling (encapsulating IPv6 packets within IPv4), and translation (converting between protocol headers). The primary advantage of IPv6 is its vastly larger address space (128 bits vs. 32 bits), solving IPv4 address exhaustion and simplifying routing with auto-configuration.
The Time to Live (TTL) field prevents packets from looping infinitely on a network by being decremented by each router; the packet is discarded when TTL reaches zero. The IP header length is calculated by multiplying the IHL (Internet Header Length) field value by 4 bytes, with a maximum of 60 bytes when IHL is 15.
The three-way handshake involves the client sending a SYN segment, the server responding with SYN-ACK, and the client finalizing with an ACK. A SYN flood attack exploits this by sending a high volume of SYN requests with spoofed IP addresses, causing the server to allocate resources for half-open connections and eventually denying service to legitimate users, affecting availability.
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