Crack (software)

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A crack is a copy of a computer program from which a copy protection applied by the manufacturer has been removed. Cracking is an activity of analyzing a computer program (usually by disassembling it ) in order to remove the copy protection . Cracking first appeared in the 1980s with the widespread use of copy protection in commercial computer games , but it is also found in every other category of computer program.

history

The first copy protection mechanisms were found in commercial software, especially computer games, as early as the late 1970s and early 1980s. Since then, there have been people who have tried to break the copy protection in order to be able to copy the software for computer users who are friends. People who did this were known as "software crackers" or " crackers " for short since the early 1980s . Individual crackers were so successful that they made cracking a kind of passion , mostly using an anonymizing cracker name ( nickname , also called pseudo or handle ). In the early 1980s this resulted in cracker groups and finally the warez scene.

Such cracker groups still exist today. Examples are RELOADED , CORE , Razor 1911 , DEViANCE , Fairlight , TSRh, FFF, SKIDROW and Eagle Soft Inc.

Types of cracks

In the past, the cracked versions were usually provided with a leader, a so-called intro or introductions screen ( cracktro ) of a cracker group. These sometimes used virtuoso graphic and acoustic effects, which often exceeded the effects of the cracked (game) program (e.g. at the time of the C-64 ), and thus gained a certain fame (see also demo scene ).

In addition to this classic meaning of a crack , there are other types today:

  • License number crack (also: Key Generator or Keymaker , KeyGen for short ) create a license number to activate a product. The programmer of the crack must in some cases have knowledge of the original license numbers in order to be able to reprogram the algorithm. As a security measure, some software manufacturers rely on activation keys with which each valid license number must also be activated via the Internet or telephone or, in the case of exclusively online applications, is checked each time it is started. In the meantime, these activation keys, such as those z. Example, in Windows XP / Vista / 7 / 8 are used to generate other keys.
  • No-CD / DVD , means that the target program, which would otherwise only run using the original CD / DVD, can also be started without it. It can be z. B. Play games without a CD / DVD. A different crack is usually required for each program version.
  • Backup CD / DVD , means that the target program no longer queries the copy protection on the CD / DVD, but a CD / DVD is still required.
  • Mini backup images (see also emulation ) are tiny images of large CDs that are only designed to simulate existing copy protection. You have the advantage of being able to patch a program (game) at will without needing a crack.
  • Serials and keys are serial numbers or (CD) keys that are required to install programs or to activate extended functions (e.g. with shareware ). Often these are also referred to as serialz. These can be calculated by license number cracks or read from the memory ("serial fishing"). The programis stoppedby means of a debugger at the point in the test routine at which the correct serial number calculated by the program is compared with the one entered by the user.

In addition, many serial numbers were not obtained through reverse engineering, but through fraud on the software manufacturer or through unauthorized disclosure by a licensed user - these can be recognized by the fact that instead of cracker pseudonyms, real names or company names are included as licensees. Such serial numbers are not counted among the cracks, since no reverse engineering is necessary to obtain them.

  • Dongle emulations use a small program to simulate the alleged existence of a physical (USB) copy protection key (e.g. Syncrosoft, Ilok, CodeMeter) on which the license activation (via the Internet or pre-authorized) is included.
  • In the narrower sense, cracks are small files that exchange or modify files, especially when software is downloaded for test purposes, in order to convert them into "full versions". Since most manufacturers now offer free "trial versions " for downloading ( shareware, demo versions ), with which almost all functions can be extensively tested, the buyer only has to reload a few small files from the Internet to permanently activate the program; this usually takes place immediately after payment. Some cracks are exact copies of these original files, others were written by crackers and manipulate the programs in such a way that program updates ("updates") can no longer be carried out (which enables illegal versions to be blocked) or product activation is bypassed permanently (a problem that is particularly Microsoft and Adobe are exposed) and the like. In most cases, complete libraries , which are otherwise automatically added when converting shareware or demo programs into fully usable full versions (downloading purchase programs), are offered for download on relevant websites or in file sharing exchanges. The same applies to serial numbers and key generators. They are also known as "crackz".

Cracks are created by cracking groups. A distinction is made between release groups and web groups : Release groups tend to work in secret and use FTP servers to distribute their releases. They want to be the first group to publish a crack on a program. A sophisticated dupecheck system is used for this, so that members of the group can check at any time which program already has cracks. Web groups publish their cracks on normal websites and make them accessible to a wide audience.

Often Cracks are also euphemistically called patch called what extent ambiguous because patches actually fix a bug in the software and often also offer manufacturer patches to their software.

Creation of cracks

To create a crack, crackers mainly use disassemblers , debuggers and hex editors . Nothing new is programmed here, only how the original code works in order to change the program in a targeted manner. Advanced knowledge of the respective assembly language is necessary.

Resetting the trial period (" Trial Reset ")

Many commercial programs that can be downloaded from the Internet have a trial period (usually 30 days) and then require registration (purchase) in order to continue to function. To reset the trial period (“ Trial Reset ”), registry keys and / or files containing information about the trial period are changed and / or deleted. Cracker develop “ trial resetters ” for certain programs or sometimes for a group of programs from the same manufacturer that do this with a click of the mouse. For some older programs, it was sufficient to change the computer's date and time at the beginning of the trial period if you wanted to work with them. Some programs can also simulate a “virtual date” and a “virtual time”. Some programs can only be used a few times during the trial period and then refuse to work until registration. (The number of program starts is recorded in the registry key and / or the hidden file; this is queried when the program is started, and when the specified number is reached, the program can only be used after registration. Here is the simulation of a wrong date and a wrong one Time pointless.) Many programs leave a hidden value in the registry when they are uninstalled, the presence of which is queried during the first installation (its absence here means that the trial period has not yet started) and during a new installation, so that it is not possible to use the Reset trial period by simply uninstalling and reinstalling. Another method for a trial reset is a virtual machine. Here a complete PC including the installed software is emulated and runs as an application in a Windows window. The state of the machine can be frozen and reset again and again. In this way, the system can be reset to the day before the installation of the demo version at any time. However, the virtual system does not have the capabilities of the PC. Computing or graphics-intensive applications run more slowly. Sometimes it is recommended to make a copy of the entire registry before installing the program. After the trial period has expired, you can reset the registry to its state before the program installation. However, all changes made by other programs or the operating system in the meantime will also be lost, and any hidden files with information about the trial period will remain unchanged. The most effective, but extreme, way to get a new trial period is to reformat the system hard drive, which will erase all of its contents, including registry entries and hidden files (the operating system will need to be reloaded and the computer set up again).

One method of making trial resets pointless is to restrict the program during the trial period (certain functions are only available in the registered version, created graphics, videos and printouts are given a watermark, the program only runs for 10-20 minutes and then switches itself off automatically off, etc.). Some programs need to be activated on the Internet for the trial period and connect to the Internet when they start to check whether the trial period has expired. The information about the trial period is therefore not stored on the user's computer, but on an external Internet server, so that manipulation is extremely difficult. A removal of this query in the program code would most likely be conceivable. The disadvantages of this procedure are that the program cannot be used without an Internet connection, even if it then no longer needs Internet access (the server for data retrieval could also be temporarily unavailable or completely switched off), and that you have to register in advance ( Data protection!), Even if you no longer use the program after the trial period has expired but want to uninstall it.

Some programs have an unlimited trial period, but are restricted as long as they are not registered.

A number of programs are also available in a free basic version and in a paid version with more functions ( freemium ). The free versions sometimes contain advertising messages ( adware ) in order to motivate the user to buy the (then often but not always ad-free) paid version (and sometimes also to buy other products from the manufacturer). Some free programs try to install other software, toolbars or similar during installation. Some commercial programs show a nagscreen during their trial period that prompts the user to register. Some security and / or cleaning programs even give false alarms during the trial period or in the free version. If you then click on this, you will be asked to register or buy the paid version.

Some programs, which can be converted from a free to a full version by registering, do not start their trial period on the day of installation, but let the user decide for himself when or whether he wants to test the additional functions at all. In the meantime, the user only has access to the functions of the free version. One example of such a program is Malwarebytes .

With some programs, especially those that are updated frequently, such as anti-virus and other security software, you only acquire a temporary license when you register (often for 1–3 years), which must be renewed for a fee after it expires. (In some cases the program does not work at all or only to a limited extent after the license expires, in others it continues to work, but can no longer be updated.)

Some programs require the purchase of multiple licenses if you want to use all functions: For example, the purchase version of DVDFab Passkey requires separate licenses for the DVD functions and for the Blu-ray functions.

Legal situation

Most commercial applications prohibit any modification of the software or even the process of disassembly in their license terms. In many countries there are laws that define the extent to which a modification of a binary program is permitted. In Germany, modifying a binary program is basically allowed as long as the original functionality of the program is not impaired. Additional functions may be implemented solely for the purpose of establishing compatibility with your own programs. A patch may only be distributed in the form of a program that changes the original file according to specifications, but not in the form of a modified copy of the original file. The right to change a program for the purpose of establishing compatibility cannot be taken for granted at international level. The prohibition of any modifications in the license conditions, however, has legally effective consequences in the rarest of cases, as this may result in a. Also the process of removing a computer virus by antivirus programs into question.

Since the legal situation is often unclear with regard to the removal of copy protection, some commercial applications use an encrypted or compressed binary code, which means that the data must be converted into executable machine code in accordance with specifications before they can be interpreted by the computer. However, since the programs have to "tell" the computer how the integrated data is to be converted, crackers can also understand how the code can be converted into an interpretable state. The software industry implements such procedures to make it more difficult for the crackers to interpret the program, but also to prevent the possibility of publishing a patch program to modify the original program, as it is no longer possible to modify the program by changing individual bytes, and the only option that remains is to distribute a completely modified original file. This is usually clearly prohibited by copyright.

See also

Web links

Individual evidence

  1. ↑ Cracker under pressure. PC-Welt , June 14, 2000, accessed February 26, 2014 .