CFL 5 Software Operating System, Network Traffic, Applications

An operating system (OS) is a collection of software that manages computer hardware resources and provides common services for computer programs. It handles tasks like scheduling, cost allocation, mass storage, printing, and more. There are various types of operating systems including real-time, multi-user, multitasking, distributed, templated, and embedded systems.

Hacking involves intruding into someone's personal information space for malicious purposes, often by exploiting security flaws to gain access to critical information or secure networks. The history of hacking began in the 1980s with events like '414' arrests and the formation of hacker groups. Notable incidents include large-scale denial-of-service attacks in 2001 and significant bank hacks in 2007. Hackers are often motivated by the challenge of solving problems and the belief in sharing information to prevent repetitive work.

Fundamental hacking skills require knowledge of computer languages. Aspiring hackers should learn Unix-like operating systems such as Linux or BSD, install them on personal machines, and understand how to use and create content for the world wide web using HTML. When initiating a hack, it is crucial to protect one's identity by masking IP addresses or using anonymous proxy servers, though governmental agencies can still trace sophisticated attacks.

When collecting data for forensic investigation, key considerations include relations, level of analysis, and sources. The process begins with client consultation to strategize data collection and preservation, as digital evidence is fragile. Computer forensic experts can retrieve data from various storage types, including active data, deleted files, and emails. After analysis, customized reports support legal cases.

Network traffic control helps manage and prioritize jobs, reducing internet bandwidth. Measuring network traffic is essential to identify and address congestion. Every system on a network has a unique 32-bit Internet Protocol (IP) address. IP addresses can be found through instant messaging, internet relay chat, websites, or email headers. Countermeasures include using proxy servers or anonymous surfing services.

The fundamental purpose of BIOS (Basic Input/Output System) is to initialize and test hardware, then load an operating system. Early IBM PC XT BIOS showed errors via screen messages and series of sounds. BIOS software is stored on a nonvolatile ROM chip. Data sources are entries in a dataset, characterized by name, type (counter, gauge, derive, absolute), and min/max values. Gauge values are stored as-is, while absolute types are for counters reset upon reading.

Web applications are frequently targeted by attacks, with a significant percentage of attacks being profit-motivated. Vulnerabilities often arise from poor coding, insecure deployment, insufficient input validation, and unguarded web application attributes. Common hacking methods involve identifying a target, finding loopholes, exploiting them, and removing traces. Attack types include authentication, authorization, client-side, command execution, and logical attacks. Techniques include brute force, cross-site scripting (XSS), SQL injection, and XPath injection.

Network hacking involves identifying target systems, gathering information, finding loopholes, and exploiting them, then erasing all traces. Port scanning is a crucial first step for attackers to identify open ports, running services, and the operating system of the target. This can be done manually or using tools like Nmap. Counter-attack strategies include using anti-port scanning software like Scan Locked and BlackICE.

ICMP (Internet Control Message Protocol) is used for error reporting and is highly useful for information gathering. It can identify live hosts, operating system information, network topography, and firewall presence. Attacks include Denial of Service (DoS) attacks, such as Ping of Death (sending oversized packets) and Smurf attacks (flooding with ping requests). Other threats include sniffers (capturing network data), keyloggers (recording keystrokes), and Trojans (remote control tools).

NetBIOS (Network Basic Input/Output System) is an API for client software to access LAN resources. It can be exploited by scanning for open ports and mapping network drives. Network forensic analysis extends traditional protocol analysis by capturing, storing, and analyzing packets over extended periods. This is used for optimizing network performance, data center consolidation, and evaluating unified communication deployments.

When choosing network forensic analysis tools, key factors to consider are performance (throughput and packet loss), visibility (number of links and topology support), capacity (real data storage and traffic filtering), redundancy (RAID usage and data recovery), and ease of use (data aggregation and segmentation). The depth of analysis, including decoding various applications and analyzing video/voice, is also critical.

Attackers can be identified by the methods they use for session hijacking: session fixation (setting a known session ID), session side-jacking (packet sniffing for session cookies), and cross-site scripting (tricking users into running malicious code). Understanding LAN email systems and web usage patterns is also important for security. Communication security involves securing these platforms against attacks.