Penetration Testing Overview

Penetration Testing

• Experienced penetration testers use various programming languages for creating scripts, including Perl, C, C++, Python, JavaScript, Visual Basic, SQL, and more.

Penetration Testing Methodologies

• A Tiger box is a collection of operating systems and hacking tools commonly found on a laptop. It assists penetration testers and security testers in vulnerability assessments and attacks.
• The white box model involves the tester having full knowledge of the network topology and technology. The tester can interview IT personnel and company employees, simplifying their task.
• The black box model restricts the tester from knowing any details about the network, requiring independent discovery.
• The gray box model combines elements of both the white and black box models, providing partial information to the tester.

Legal Considerations

• Technology laws evolve rapidly, making it crucial to understand local regulations. These laws vary geographically, so it is essential to be aware of permitted and prohibited activities.
• Certain tools might be illegal to possess. It is advisable to consult local law enforcement agencies before installing hacking tools.
• Written laws are subject to interpretation, and governments are increasing penalties for cybercrimes.

Illegal Activities

• Accessing a computer without authorization is illegal.
• Other prohibited actions include:
  • Installing worms or viruses
  • Denial of Service attacks
  • Denying users access to network resources
• It is important to ensure actions do not hinder customer workflow.

Ethical Hacking

• Ethical hacking requires:
  • Knowledge of network and computer technology
  • Effective communication with management and IT personnel
  • Understanding relevant laws
  • Proficiency in utilizing necessary tools

Ethical Hacking Course Outline

• The course will cover:
  • Relevant networking technologies
  • Basic cryptographic concepts
  • Case studies of secure applications
  • Unconventional attacks
  • Tool demonstrations

Networking Concepts

• A computer network is a communication system that interconnects computers or hosts.
• The primary reasons for using a network include:
  • Enhanced connectivity
  • Improved communication
  • Easier resource sharing
  • Bringing people together

Types of Networks

• A Local Area Network (LAN) connects hosts within a small geographical area, such as a room, building, or campus. It offers faster speeds and lower costs.
• A Wide Area Network (WAN) connects hosts spread over a wider geographic range, including campuses, cities, countries, or continents. WANs are slower and more expensive.

Data Communication over Networks

• Two main approaches for data communication:
  • Circuit switching establishes a dedicated communication path between two stations, following a fixed route with a logical channel on each physical link.
  • Packet switching involves transmitting data in short packets. Each packet contains a header with routing information.

Circuit Switching

• Circuit switching requires three steps:
  • Connection establishment: before data transmission
  • Data transfer: at maximum speed
  • Connection termination: after data transmission for resource deallocation

Circuit Switching Drawbacks

• Channel capacity is dedicated for the duration of communication, suitable for voice communication but inefficient for bursty traffic like data.
• Initial delay for connection establishment.

Packet Switching

• A modern form of long-distance data communication that shares network resources and allows for better utilization.
• Data is transmitted in short packets (around kilobytes).
• A message is divided into smaller chunks called packets, each containing a header with routing information.

Packet Switching Concept

• The store-and-forward concept is employed, where intermediate nodes receive the entire packet, determine the route, and forward it accordingly.

Packet Switching Advantages

• Improved link utilization due to resource sharing.
• Suitability for bursty computer traffic.
• Easy buffering and data rate conversion.
• Packet prioritization is possible if required.

Packet Transmission Approaches

• Two approaches for packet transmission:
  • Virtual circuits: similar to circuit switching but shares links.
  • Datagrams: each packet is transmitted independently without route establishment.

Virtual Circuit Approach

• Analogy: Telephone system
• A route is set up before packet transmission.
• Packets follow the same path but do not have dedicated links.
• Intermediate nodes use a table created during route establishment for packet forwarding.

Datagram Approach

• Analogy: Postal system
• No pre-established route.
• Packets are transmitted independently with no history maintained.
• Dynamic routing decisions are made by intermediate nodes using a routing table.

Datagram Approach Problems

• Packets may be delivered out of order.
• Packet loss during temporary node crashes.
• Duplicate packets may occur.
• Routes packets through point-to-point links.

Layered Network Architecture

• The layered network architecture defines communication functions for efficient data transfer.
  • Application layer: interface for user applications.
  • Presentation layer: provides data independence.
  • Session layer: manages network sessions.
  • Transport layer: ensures reliable end-to-end data transfer with error recovery and flow control.
  • Network layer: performs packet routing and addressing.
  • Data link layer: manages physical link errors.
  • Physical layer: governs physical transmission of data.

Data Flow

• Data flows through the layers, starting from the application layer down to the physical layer and back up, interacting with the corresponding layers on the receiving device.

Internetworking Devices

• Hub: extends the coverage of a single LAN.
• Bridge/Layer-2 switch: connects multiple LANs, operating at the data link layer level.
• Router/Layer-3 switch: connects various LANs and WANs, operating at the network layer level.

Typical Internetworking Structure

• Demonstrates connections between various devices and networks, including LANs, WANs, routers, and switches.

TCP/IP Protocol Stack

• TCP/IP (Transmission Control Protocol/Internet Protocol) is a foundational protocol for internet communication.
• It enables computers to communicate and share resources effectively.

TCP/IP Standard

• It serves as a standard to bridge the gap between incompatible platforms.
• Development of TCP/IP began in the 1970s, funded by the US Military's Advanced Research Project Agency (ARPA)

Network Layering in TCP/IP

• TCP/IP follows a simplified four-layer model instead of the seven-layer OSI model.

TCP/IP Layers

• The TCP/IP protocol stack comprises four layers:
  • Application
  • Transport
  • Internet
  • Network Access

TCP/IP Encapsulation

• TCP/IP encapsulates data by adding headers at each layer, providing information for routing and flow control.

TFTP Encapsulation

• Data is encapsulated with headers for TFTP, UDP, IP, and Ethernet at each layer.

The IP Layer

• The IP layer provides a connectionless, unreliable delivery system for packets.
  • Each packet functions independently.
  • It does not maintain a history.
  • Packets must contain source and destination addresses.
  • Delivery of packets is not guaranteed.

IP Layer Encapsulation

• The IP layer receives data from higher layers (TCP or UDP), prepends a header (minimum 20 bytes) with routing and flow control information.

IP Datagram Format

• An IP datagram includes:
  • Version (VER)
  • Header Length (HLEN)
  • Service Type
  • Total Length
  • Identification
  • Flags
  • Fragment Offset
  • Time to Live
  • Protocol
  • Header Checksum
  • Source IP Address
  • Destination IP Address
  • Options
  • Data

IP Header Fields

• Version (VER): Specifies the version of the IP protocol (typically 4).
• Header Length (HLEN): Describes the header length in 32-bit words (minimum 5, maximum 15).
• Service Type: Indicates the priority and type of service for the data.
• Total Length: Specifies the total length of the IP datagram, including header and data.
• Identification: A unique identifier for each datagram, used for fragmentation and reassembly.
• Flags: Control flags related to fragmentation, such as Don't Fragment (DF) and More Fragments (MF).
• Fragment Offset: Indicates the position of a fragment within an original datagram.
• Time to Live (TTL): Determines the maximum number of hops a datagram can traverse before being discarded.
• Protocol: Identifies the higher-layer protocol (e.g., TCP or UDP) carried within the datagram.
• Header Checksum: A checksum of the header, used to detect errors in the header during transmission.
• Source IP Address: The IP address of the sending host.
• Destination IP Address: The IP address of the receiving host.
• Options: Optional fields for advanced routing and security features.
• Data: The actual data being transmitted.