Learn about OSI Model

Before we dive into the OSI model, let’s first consider how it came to be. Back in the early 1980s, The IT world becoming very complex without a standardized framework. The International Organization for Standardization (ISO) saw this issue and decided to come up with framework with researchers. They brought together experts to come up with conceptualized network communication

Layer 1: Physical Layer- Imagine the Physical Layer as the foundation of your house. We encounter the tangible components of networking infrastructure. Think of the Ethernet cables connecting through office cubicles or the electromagnetic waves pulsating from Wi-Fi routers. These physical connections serve as the transmission media through which raw data bits traverse the network.

Example: Ethernet cables, Wi-Fi signals

Security Concerns: This layer is vulnerable to physical tampering. Think about someone cutting your cable or using a device to intercept wireless signals.

Layer 2: Data Link Layer: Moving up, the Data Link Layer ensures that the data bits from the Physical Layer are organized into data packets and delivered to the correct computer or device on the network. It’s like organizing and addressing the invitations to a party to ensure they reach the right destination.

Security Concerns: Hacker can perform ARP (Address Resolution Protocol) poisoning, where attackers manipulate MAC address mappings to intercept traffic.

Layer 3: Network Layer: The Network Layer is like a GPS for data packets—it decides the best routes for the data to travel across different networks. This layer uses IP addresses to guide the packets to their destination across the network.

Security Concerns: IP spoofing is a major threat at this layer, where attackers disguise the origin of the data packets to bypass security. Also, at the Network Layer, hackers exploit weaknesses in routing protocols like RIP (Routing Information Protocol) or OSPF (Open Shortest Path First) to manipulate routing tables and redirect traffic to malicious destinations. IP spoofing allows attackers to impersonate trusted entities and bypass security measures.

Layer 4: Transport Layer: At the Transport Layer, think of it as the quality control supervisor for data transmission. It makes sure the entire message gets from one end to the other reliably and in the right order. It’s where TCP (for reliable connections) and UDP (for faster, less reliable connections) come into play.

Security Concerns: Hacker can perform like launch SYN flood attacks, overwhelming servers with connection requests and causing service disruption or hacker can perform DNS spoofing manipulates DNS resolution to redirect users to fraudulent websites.

Layer 5: Session Layer: The Session Layer manages sessions between applications. This is where communications are controlled, allowing for opening, closing, or managing a pause in communications between two network. It essentially manages these connections to ensure that data exchange sessions are set up, managed, and terminated gracefully.

Security Concerns: One notable security issue here is session hijacking, where attackers take over an ongoing session to steal data or impersonate the user.

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Layer 6: Presentation Layer: This layer is like a translator for the network. The Presentation Layer translates data from a format the application layer can accept into a format that can be sent across the network. It handles data encryption, data compression, and conversion between data formats.

Security Concerns: The main security concerns involve data encryption and proper data formatting to prevent data corruption and loss of information integrity.

Layer 7: Application Layer: At the top of the layer, the Application Layer provides services directly to the user’s applications, such as email, file transfer, and browsing. This layer interacts with software applications

Security Concerns: Common threats include viruses, worms, and trojan horses that can be embedded in the application’s data. Also, this layer is prone to various forms of application-level attacks like SQL injection and cross-site scripting (XSS).