Programming Requirements

Quality requirements

Whatever the approach to software development may be, the final program must satisfy some fundamental properties. The following properties are among the most relevant:

• Reliability: how often the results of a program are correct. This depends on conceptual correctness of algorithms, and minimization of programming mistakes, such as mistakes in resource management (e.g., buffer overflows and race conditions) and logic errors (such as division by zero or off-by-one errors).
• Robustness: how well a program anticipates problems not due to programmer error. This includes situations such as incorrect, inappropriate or corrupt data, unavailability of needed resources such as memory, operating system services and network connections, and user error.
• Usability: the ergonomics of a program: the ease with which a person can use the program for its intended purpose, or in some cases even unanticipated purposes. Such issues can make or break its success even regardless of other issues. This involves a wide range of textual, graphical and sometimes hardware elements that improve the clarity, intuitiveness, cohesiveness and completeness of a program's user interface.
• Portability: the range of computer hardware and operating system platforms on which the source code of a program can be compiled/interpreted and run. This depends on differences in the programming facilities provided by the different platforms, including hardware and operating system resources, expected behaviour of the hardware and operating system, and availability of platform specific compilers (and sometimes libraries) for the language of the source code.
• Maintainability: the ease with which a program can be modified by its present or future developers in order to make improvements or customizations, fix bugs and security holes, or adapt it to new environments. Good practices during initial development make the difference in this regard. This quality may not be directly apparent to the end user but it can significantly affect the fate of a program over the long term.
• Efficiency/performance: the amount of system resources a program consumes (processor time, memory space, slow devices such as disks, network bandwidth and to some extent even user interaction): the less, the better. This also includes correct disposal of some resources, such as cleaning up temporary files and lack of memory leaks.

Readability of source code

In computer programming, readability refers to the ease with which a human reader can comprehend the purpose, control flow, and operation of source code. It affects the aspects of quality above, including portability, usability and most importantly maintainability.
Readability is important because programmers spend the majority of their time reading, trying to understand and modifying existing source code, rather than writing new source code. Unreadable code often leads to bugs, inefficiencies, and duplicated code. A study^[14] found that a few simple readability transformations made code shorter and drastically reduced the time to understand it.
Following a consistent programming style often helps readability. However, readability is more than just programming style. Many factors, having little or nothing to do with the ability of the computer to efficiently compile and execute the code, contribute to readability.^[15] Some of these factors include:

• Different indentation styles (whitespace)
• Comments
• Decomposition
• Naming conventions for objects (such as variables, classes, procedures, etc.)

Various visual programming languages have also been developed with the intent to resolve readability concerns by adopting non-traditional approaches to code structure and display.

Kevin Mitnick Social Engineer

Kevin David Mitnick (born on August 6, 1963) is an American computer security consultant, author, convicted criminal, and hacker. In the late 20th century, he was convicted of various computer and communications-related crimes. At the time of his arrest, he was the most-wanted computer criminal in the United States.^[1]

At age 12, Mitnick used social engineering to bypass the punchcard system used in the Los Angeles bus system. After a friendly bus driver told him where he could buy his own ticket punch, he could ride any bus in the greater LA area using unused transfer slips he found in the trash. Social engineering became his primary method of obtaining information, including user-names and passwords and modem phone numbers.^[3]
Mitnick first gained unauthorized access to a computer network in 1979, at 16, when a friend gave him the phone number for the Ark, the computer system Digital Equipment Corporation (DEC) used for developing their RSTS/E operating system software. He broke into DEC's computer network and copied their software, a crime he was charged with and convicted of in 1988. He was sentenced to 12 months in prison followed by three years of supervised release. Near the end of his supervised release, Mitnick hacked into Pacific Bell voice mail computers. After a warrant was issued for his arrest, Mitnick fled, becoming a fugitive for two and a half years.

After a well-publicized pursuit, the FBI arrested Mitnick on February 15, 1995, at his apartment in Raleigh, North Carolina, on federal offenses related to a 2½-year period of computer hacking.^[6]

• Vulnerability
  • Eavesdropping
• Exploits
  • Trojans
  • Viruses and worms
  • Denial of service
• Payloads
  • Rootkits
  • Keyloggers

Vulnerability Computing

In computer security, a vulnerability is a weakness which allows an attacker to reduce a system's information assurance. Vulnerability is the intersection of three elements: a system susceptibility or flaw, attacker access to the flaw, and attacker capability to exploit the flaw.^[1] To exploit a vulnerability, an attacker must have at least one applicable tool or technique that can connect to a system weakness. In this frame, vulnerability is also known as the attack surface.
Vulnerability management is the cyclical practice of identifying, classifying, remediating, and mitigating vulnerabilities"^[2] This practice generally refers to software vulnerabilities in computing systems.
A security risk may be classified as a vulnerability. The usage of vulnerability with the same meaning of risk can lead to confusion. The risk is tied to the potential of a significant loss. Then there are vulnerabilities without risk: for example when the affected asset has no value. A vulnerability with one or more known instances of working and fully implemented attacks is classified as an exploitable vulnerability — a vulnerability for which an exploit exists. The window of vulnerability is the time from when the security hole was introduced or manifested in deployed software, to when access was removed, a security fix was available/deployed, or the attacker was disabled—see zero-day attack.
Security bug (security defect) is a narrower concept: there are vulnerabilities that are not related to software: hardware, site, personnel vulnerabilities are examples of vulnerabilities that are not software security bugs.
Constructs in programming languages that are difficult to use properly can be a large source of vulnerabilities.

Hacking Attacks

A typical approach in an attack on Internet-connected system is:

1. Network enumeration: Discovering information about the intended target.
2. Vulnerability analysis: Identifying potential ways of attack.
3. Exploitation: Attempting to compromise the system by employing the vulnerabilities found through the vulnerability analysis.^[16]

In order to do so, there are several recurring tools of the trade and techniques used by computer criminals and security experts.

Security exploits

Main article: Exploit (computer security)

A security exploit is a prepared application that takes advantage of a known weakness. Common examples of security exploits are SQL injection, Cross Site Scripting and Cross Site Request Forgery which abuse security holes that may result from substandard programming practice. Other exploits would be able to be used through FTP, HTTP, PHP, SSH, Telnet and some web-pages. These are very common in website/domain hacking.

Techniques

This section does not cite any references or sources. Please help improve this section by adding citations to reliable sources. Unsourced material may be challenged and removed. (August 2011)

Vulnerability scanner

Main article: Vulnerability scanner

A vulnerability scanner is a tool used to quickly check computers on a network for known weaknesses. Hackers also commonly use port scanners. These check to see which ports on a specified computer are "open" or available to access the computer, and sometimes will detect what program or service is listening on that port, and its version number. (Note that firewalls defend computers from intruders by limiting access to ports/machines both inbound and outbound, but can still be circumvented.)

Password cracking

Main article: Password cracking

Password cracking is the process of recovering passwords from data that has been stored in or transmitted by a computer system. A common approach is to repeatedly try guesses for the password.

Packet sniffer

Main article: Packet sniffer

A packet sniffer is an application that captures data packets, which can be used to capture passwords and other data in transit over the network.

Spoofing attack (Phishing)

Main article: Spoofing attack

A spoofing attack involves one program, system, or website successfully masquerading as another by falsifying data and thereby being treated as a trusted system by a user or another program. The purpose of this is usually to fool programs, systems, or users into revealing confidential information, such as user names and passwords, to the attacker.

Rootkit

Main article: Rootkit

A rootkit is designed to conceal the compromise of a computer's security, and can represent any of a set of programs which work to subvert control of an operating system from its legitimate operators. Usually, a rootkit will obscure its installation and attempt to prevent its removal through a subversion of standard system security. Rootkits may include replacements for system binaries so that it becomes impossible for the legitimate user to detect the presence of the intruder on the system by looking at process tables.

Social engineering

Main article: Social engineering (computer security)

When a hacker, typically a black hat, is in the second stage of the targeting process, he or she will typically use some social engineering tactics to get enough information to access the network. A common practice for hackers who use this technique, is to contact the system administrator and play the role of a user who cannot get access to his or her system. Hackers who use this technique have to be quite savvy and choose the words they use carefully, in order to trick the system administrator into giving them information. In some cases only an employed help desk user will answer the phone and they are generally easy to trick. Another typical hacker approach is for the hacker to act like a very angry supervisor and when the his/her authority is questioned they will threaten the help desk user with their job. Social engineering is very effective because users are the most vulnerable part of an organization. All the security devices and programs in the world won't keep an organization safe if an employee gives away a password. Black hat hackers take advantage of this fact. Social engineering can also be broken down into four sub-groups. These are intimidation, helpfulness, technical, and name-dropping.

• Intimidation As stated above, with the angry supervisor, the hacker attacks the person who answers the phone with threats to their job. Many people at this point will accept that the hacker is a supervisor and give them the needed information.
• Helpfulness Opposite to intimidation, helpfulness is taking advantage of a person's natural instinct to help someone with a problem. The hacker will not get angry and instead act very distressed and concerned. The help desk is the most vulnerable to this type of social engineering, because it generally has the authority to change or reset passwords, which is exactly what the hacker needs.
• Name-dropping Simply put, the hacker uses the names of advanced users as "key words", and gets the person who answers the phone to believe that they are part of the company because of this. Some information, like web page ownership, can be obtained easily on the web. Other information such as president and vice president names might have to be obtained via dumpster diving.
• Technical Using technology is also a great way to get information. A hacker can send a fax or an email to a legitimate user in hopes to get a response containing vital information. Many times the hacker will act like he/she is involved with law enforcement and needs certain data for record keeping purposes or investigations.

Trojan horses

Main article: Trojan horse (computing)

A Trojan horse is a program which seems to be doing one thing, but is actually doing another. A trojan horse can be used to set up a back door in a computer system such that the intruder can gain access later. (The name refers to the horse from the Trojan War, with the conceptually similar function of deceiving defenders into bringing an intruder inside.)

Viruses

Main article: Computer virus

A virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. Therefore, a computer virus behaves in a way similar to a biological virus, which spreads by inserting itself into living cells.

While some are harmless or mere hoaxes, most computer viruses are considered malicious.

Worms

Main article: Computer worm

Like a virus, a worm is also a self-replicating program. A worm differs from a virus in that it propagates through computer networks without user intervention. Unlike a virus, it does not need to attach itself to an existing program. Many people conflate the terms "virus" and "worm", using them both to describe any self-propagating program.

Key loggers

Main article: Keystroke logging

A key logger is a tool designed to record ('log') every keystroke on an affected machine for later retrieval. Its purpose is usually to allow the user of this tool to gain access to confidential information typed on the affected machine, such as a user's password or other private data. Some key loggers use virus-, trojan-, and rootkit-like methods to remain active and hidden. However, some key loggers are used in legitimate ways and sometimes to even enhance computer security. As an example, a business might have a key logger on a computer used at a point of sale and data collected by the key logger could be used for catching employee fraud.

Types of hackers

White hat

A white hat hacker breaks security for non-malicious reasons, perhaps to test their own security system or while working for a security company which makes security software. The term "white hat" in Internet slang refers to an ethical hacker. This classification also includes individuals who perform penetration tests and vulnerability assessments within a contractual agreement. The EC-Council,^[7] also known as the International Council of Electronic Commerce Consultants, is one of those organisations that have developed certifications, courseware, classes, and online training covering the diverse arena of Ethical Hacking.^[6]

Black hat

A "black hat" hacker is a hacker who "violates computer security for little reason beyond maliciousness or for personal gain" (Moore, 2005).^[8] Black hat hackers form the stereotypical, illegal hacking groups often portrayed in popular culture, and are "the epitome of all that the public fears in a computer criminal".^[9] Black hat hackers break into secure networks to destroy data or make the network unusable for those who are authorized to use the network. They choose their targets using a two-pronged process known as the "pre-hacking stage".

Part 1: Targeting

The hacker determines what network to break into during this phase. The target may be of particular interest to the hacker, either politically or personally, or it may be picked at random. Next, they will port scan a network to determine if it is vulnerable to attacks, which is just testing all ports on a host machine for a response. Open ports—those that do respond—will allow a hacker to access the system.

Part 2: Research and Information Gathering

It is in this stage that the hacker will visit or contact the target in some way in hopes of finding out vital information that will help them access the system. The main way that hackers get desired results from this stage is from "social engineering", which will be explained below. Aside from social engineering, hackers can also use a technique called "dumpster diving". Dumpster diving is when a hacker will literally search through users' garbage in hopes of finding documents that have been thrown away, which may contain information a hacker can use directly or indirectly, to help them gain access to a network.

Part 3: Finishing The Attack

This is the stage when the hacker will invade the primary target that he/she was planning to attack or steal from. Many "hackers" will be caught after this point, lured in or grabbed by any data also known as a honeypot (a trap set up by computer security personnel).

Grey hat

Main article: Grey hat

A grey hat hacker is a combination of a Black Hat and a White Hat Hacker. A Grey Hat Hacker may surf the internet and hack into a computer system for the sole purpose of notifying the administrator that their system has been hacked, for example. Then they may offer to repair their system for a small fee.^[9]

Elite hacker

A social status among hackers, elite is used to describe the most skilled. Newly discovered exploits will circulate among these hackers. Elite groups such as Masters of Deception conferred a kind of credibility on their members.^[10]

Script kiddie

A script kiddie (or skiddie) is a non-expert who breaks into computer systems by using pre-packaged automated tools written by others, usually with little understanding of the underlying concept—hence the term script (i.e. a prearranged plan or set of activities) kiddie (i.e. kid, child—an individual lacking knowledge and experience, immature).^[11]

Neophyte

A neophyte, "n00b", or "newbie" is someone who is new to hacking or phreaking and has almost no knowledge or experience of the workings of technology, and hacking.^[9]

Blue hat

A blue hat hacker is someone outside computer security consulting firms who is used to bug test a system prior to its launch, looking for exploits so they can be closed. Microsoft also uses the term BlueHat to represent a series of security briefing events.^[12][13][14]

Hacktivist

A hacktivist is a hacker who utilizes technology to announce a social, ideological, religious, or political message. In general, most hacktivism involves website defacement or denial-of-service attacks.

Nation state

Intelligence agencies and cyberwarfare operatives of nation states.^[15]

Organized criminal gangs

Criminal activity carried on for profit.^[15]

Bots

Bots are automated software tools, some freeware, that are available for the use of any type of hacker.^[15]

Internet protocol suite

The Internet protocol suite is the set of communications protocols used for the Internet and similar networks, and generally the most popular protocol stack for wide area networks. It is commonly known as TCP/IP, because of its most important protocols: Transmission Control Protocol (TCP) and Internet Protocol (IP), which were the first networking protocols defined in this standard. It is occasionally known as the DoD model due to the foundational influence of the ARPANET in the 1970s (operated by DARPA, an agency of the United States Department of Defense).
TCP/IP provides end-to-end connectivity specifying how data should be formatted, addressed, transmitted, routed and received at the destination. It has four abstraction layers which are used to sort all Internet protocols according to the scope of networking involved.^[1][2] From lowest to highest, the layers are:

1. The link layer contains communication technologies for a local network.
2. The internet layer (IP) connects local networks, thus establishing internetworking.
3. The transport layer handles host-to-host communication.
4. The application layer contains all protocols for specific data communications services on a process-to-process level. For example, HTTP specifies the web browser communication with a web server.

The TCP/IP model and related protocols are maintained by the Internet Engineering Task Force (IETF).