In the computer security context, a hacker is someone who seeks and exploits weaknesses in a computer system or computer network. Hackers may be motivated by a multitude of reasons, such as profit, protest, or challenge. The subculture that has evolved around hackers is often referred to as the computer underground and is now a known community. While other uses of the word hacker exist that are not related to computer security, such as referring to someone with an advanced understanding of computers and computer networks, they are rarely used in mainstream context. They are subject to the longstanding hacker definition controversy about the term's true meaning. In this controversy, the term hacker is reclaimed by computer programmers who argue that someone who breaks into computers, whether computer criminal (black hats) or computer security expert (white hats), is more appropriately called a cracker instead. Some white hat hackers claim that they also deserve the title hacker, and that only black hats should be called crackers.
Bruce Sterling traces part of the roots of the computer underground to the Yippies, a 1960s counterculture movement which published the Technological Assistance Program (TAP) newsletter.TAP was a phone phreaking newsletter that taught techniques for unauthorized exploration of the phone network. Many people from the phreaking community are also active in the hacking community even today, and vice versa.
Several subgroups of the computer underground with different attitudes use different terms to demarcate themselves from each other, or try to exclude some specific group with which they do not agree.
Eric S. Raymond, author of The New Hacker's Dictionary, advocates that members of the computer underground should be called crackers. Yet, those people see themselves as hackers and even try to include the views of Raymond in what they see as a wider hacker culture, a view that Raymond has harshly rejected. Instead of a hacker/cracker dichotomy, they emphasize a spectrum of different categories, such as white hat, grey hat, black hat and script kiddie. In contrast to Raymond, they usually reserve the term cracker for more malicious activity.
According to Ralph D. Clifford, a cracker or cracking is to "gain unauthorized access to a computer in order to commit another crime such as destroying information contained in that system". These subgroups may also be defined by the legal status of their activities.
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, also known as the International Council of Electronic Commerce Consultants, is one of those organizations that have developed certifications, courseware, classes, and online training covering the diverse arena of Ethical Hacking.
A "black hat" hacker is a hacker who "violates computer security for little reason beyond maliciousness or for personal gain" (Moore, 2005). 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". Black hat hackers break into secure networks to destroy data or make the network unusable for those who are authorized to use the network. Black hat hackers also are referred to as the "crackers" within the security industry and by modern programmers. Crackers keep the awareness of the vulnerabilities to themselves and do not notify the general public or manufacturer for patches to be applied. Individual freedom and accessibility is promoted over privacy and security. Once they have gained control over a system, they may apply patches or fixes to the system only to keep their reigning control. Richard Stallman invented the definition to express the maliciousness of a criminal hacker versus a white hat hacker who performs hacking duties to identify places to repair.
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 a security defect, for example. They may then offer to correct the defect for a fee.
A script kiddie (also known as a skid 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).
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.
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.
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.
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. (Firewalls defend computers from intruders by limiting access to ports and machines, but they can still be circumvented.)
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.
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)
A spoofing attack involves one program, system or website that successfully masquerades as another by falsifying data and is thereby treated as a trusted system by a user or another program—usually to fool programs, systems or users into revealing confidential information, such as user names and passwords.
A rootkit is a program that uses low-level, hard-to-detect methods to subvert control of an operating system from its legitimate operators. Rootkits usually obscure their installation and attempt to prevent their removal through a subversion of standard system security. They may include replacements for system binaries, making it virtually impossible for them to be detected by checking process tables.
In the second stage of the targeting process, hackers often use Social engineering tactics to get enough information to access the network. They may contact the system administrator and pose as a user who cannot get access to his or her system. This technique is portrayed in the 1995 film Hackers, when protagonist Dade "Zero Cool" Murphy calls a somewhat clueless employee in charge of security at a TV network. Posing as an accountant working for the same company, Dade tricks the employee into giving him the phone number of a modem so he can gain access to the company's computer system.
Hackers who use this technique must have cool personalities, and be familiar with their target's security practices, in order to trick the system administrator into giving them information. In some cases, a help-desk employee with limited security experience will answer the phone and be relatively easy to trick. Another approach is for the hacker to pose as an angry supervisor, and when his/her authority is questioned, threaten to fire the help-desk worker. Social engineering is very effective because users are the most vulnerable part of an organization. No security devices or programs can keep an organization safe if an employee reveals a password to an unauthorized person.
Social engineering can be broken down into four sub-groups:
Intimidation As in the "angry supervisor" technique above, the hacker convinces the person who answers the phone that their job is in danger unless they help them. At this point, many people accept that the hacker is a supervisor and give them the information they seek.
Helpfulness The opposite of intimidation, helpfulness exploits many people's natural instinct to help others solve problems. Rather than acting angry, the hacker acts distressed and concerned. The help desk is the most vulnerable to this type of social engineering, as (a.) its general purpose is to help people; and (b.) it usually has the authority to change or reset passwords, which is exactly what the hacker wants.
Name-dropping The hacker uses names of authorized users to convince the person who answers the phone that the hacker is a legitimate users him- or herself. Some of these names, such as those of webpage owners or company officers, can easily be obtained online. Hackers have also been known to obtain names by examining discarded documents (so-called "dumpster diving").
Technical Using technology is also a way to get information. A hacker can send a fax or email to a legitimate user, seeking a response that contains vital information. The hacker may claim that he or she is involved in law enforcement and needs certain data for an investigation, or for record-keeping purposes.
A Trojan horse is a program that seems to be doing one thing but is actually doing another. It can be used to set up a back door in a computer system, enabling the intruder to 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 into a protected area.)
A virus is a self-replicating program that spreads by inserting copies of itself into other executable code or documents. By doing this, it behaves similarly to a biological virus, which spreads by inserting itself into living cells. While some viruses are harmless or mere hoaxes, most are considered malicious.
Like a virus, a worm is also a self-replicating program. It differs from a virus in that (a.) it propagates through computer networks without user intervention; and (b.) does not need to attach itself to an existing program. Nonetheless, many people use the terms "virus" and "worm" interchangeably to describe any self-propagating program.
A keylogger is a tool designed to record ("log") every keystroke on an affected machine for later retrieval, usually to allow the user of this tool to gain access to confidential information typed on the affected machine. Some keyloggers use virus-, trojan-, and rootkit-like methods to conceal themselves. However, some of them are used for legitimate purposes, even to enhance computer security. For example, a business may maintain a keylogger on a computer used at a point of sale to detect evidence of employee fraud.
Tools and Procedures
A thorough examination of hacker tools and procedures may be found in Cengage Learning's E|CSA certification workbook.
Jacob Appelbaum is an advocate, security researcher, and developer for the Tor project. He speaks internationally for usage of Tor by human rights groups and others concerned about Internet anonymity and censorship.
Ed Cummings (also known as Bernie S) is a longstanding writer for 2600: The Hacker Quarterly. In 1995, he was arrested and charged with possession of technology that could be used for fraudulent purposes, and set legal precedents after being denied both a bail hearing and a speedy trial.
Dan Kaminsky is a DNS expert who exposed multiple flaws in the protocol and investigated Sony's rootkit security issues in 2005. He has spoken in front of the US Senate on technology issues.
The computer underground has produced its own specialized slang, such as 1337speak. Its members often advocate freedom of information, strongly opposing the principles of copyright, as well as the rights of free speech and privacy. Writing software and performing other activities to support these views is referred to as hacktivism. Some consider illegal cracking ethically justified for these goals; a common form is website defacement. The computer underground is frequently compared to the Wild West. It is common for hackers to use aliases to conceal their identities.
The computer underground is supported by regular real-world gatherings called hacker conventions or "hacker cons". These events include SummerCon (Summer), DEF CON, HoHoCon (Christmas), ShmooCon (February), BlackHat, Chaos Communication Congress, AthCon, Hacker Halted, and H.O.P.E... Local Hackfest groups organize and compete to develop their skills to send a team to a prominent convention to compete in group pentesting, exploit and forensics on a larger scale. Hacker groups became popular in the early 1980s, providing access to hacking information and resources and a place to learn from other members. Computer bulletin board systems (BBSs), such as the Utopias, provided platforms for information-sharing via dial-up modem. Hackers could also gain credibility by being affiliated with elite groups.
Hacking and the law
Article 138ab of Wetboek van Strafrecht prohibits computervredebreuk which is defined as intruding an automated work or a part thereof with intention and against the law. Intrusion is defined as access by means of:
The most notable hacker-oriented print publications are Phrack, Hakin9 and 2600: The Hacker Quarterly. While the information contained in hacker magazines and ezines was often outdated by the time they were published, they enhanced their contributors's reputations by documenting their successes.