Software cracking
From Wikipedia, the free encyclopedia
Software cracking is the modification of software to remove protection methods: copy prevention, trial/demo version, serial number, hardware key, CD check or software annoyances like nag screens and adware.
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[edit] Legality
The distribution and use of cracked copies is illegal in almost every developed country. There have been many lawsuits over cracking software, but most have been to do with the distribution of the duplicated product rather than the process of defeating the protection, due to the difficulty of constructing legally sound proof of individual guilt in the latter instance. In the United States, the passing of the Digital Millennium Copyright Act (DMCA) legislation made software cracking, as well as the distribution of information which enables software cracking, illegal. However, the law has hardly been tested in the U.S. judiciary in cases of reverse engineering for personal use only. The European Union passed the European Union Copyright Directive in May 2001, making software copyright infringement illegal in member states once national legislation has been enacted pursuant to the directive.
[edit] Methods
The most common software crack is the modification of an application's binary to cause or prevent a specific key branch in the program's execution. This is accomplished by reverse engineering the compiled program code using a debugger such as SoftICE, OllyDbg, GDB, or MacsBug until the software cracker reaches the subroutine that contains the primary method of protecting the software (or by disassembling an executable file with a program such as IDA). The binary is then modified using the debugger or a hex editor in a manner that replaces a prior branching opcode with its complement or a NOP opcode so the key branch will either always execute a specific subroutine or skip over it. Almost all common software cracks are a variation of this type. Software developers are constantly developing techniques such as code obfuscation, encryption, and self-modifying code to make this modification increasingly difficult.
A specific example of this technique is a crack that removes the expiration period from a time-limited trial of an application. These cracks are usually programs that patch the program executable and sometimes the .dll or .so linked to the application. Similar cracks are available for software that requires a hardware dongle. A company can also break the copy preventions of programs that they have legally purchased but that are licensed to particular hardware, so that there is no risk of downtime due to hardware failure (and, of course, no need to restrict oneself to running the software on bought hardware only).
In other cases, it might be possible to decompile a program in order to get access to the original source code or code on a level higher than machine code. This is often possible with scripting languages. An example is cracking (or debugging) on the .NET platform where one might consider manipulating CIL to achieve one's needs.
There are a number of sites on the Internet that let users download cracks for popular games and applications (although at the danger of acquiring malicious software that is sometimes distributed via such sites). Although these cracks are used by legal buyers of software they can also be used by people who have downloaded or otherwise obtained pirated software (often through P2P networks).
[edit] Effects
The most visible and controversial effect of software cracking is the releasing of fully operable proprietary software without any copy protection. Software companies represented by the Business Software Alliance estimate and claim losses due to piracy.
Software cracking has also had positive effects for the industry, as well as general consumers. For example, the warez groups have helped increase the popularity of file formats such as Xvid and MP3.
[edit] Hazards
Due to the potential legal repercussions, many individuals who release cracks to the public for commercially available software choose to remain anonymous. This can often create confusion as the available documentation is often sparse. It is beyond the ability of most to determine the exact operations the crack will execute.
As an example, several spyware removal utilities have rules in place that regard certain cracks as having a malicious payload such as a hidden DDOS daemon.[citation needed]
[edit] History
The first software copy protection was on early Apple II and Commodore 64 software. Game publishers, in particular, carried on an arms race with software crackers. More recently, publishers have resorted to increasingly complex countermeasures, such as StarForce, to try to stop unauthorized copying of their software.
Unlike modern computers that use standardized drivers and a system BIOS to manage device communications, the Apple II DOS directly controlled the step motor that moves the floppy drive head, and also directly interpreted the raw data (known as nibbles) read from each track to find the data sectors. This allowed complex disk-based software copy protection, by storing data on half tracks (0 1 2.5 3.5 5 6...), quarter tracks (0 1 2.25 3.75 5 6...), and any combination thereof. In addition tracks did not need to be perfect rings, but could be sectioned so that sectors could be staggered across overlapping offset tracks, the most extreme version being known as spiral tracking. It was also discovered that many floppy drives do not have a fixed upper limit to head movement, and it was sometimes possible to write an additional 36th track above the normal 35 tracks. The standard Apple II DOS copy programs could not read such protected floppy disks, since the standard DOS assumed all disks had a uniform 35 track, 13 or 16 sector layout. Special nibble-copy programs such as Locksmith and Copy II Plus could sometimes duplicate these disks by using a reference library of known protection methods, but when protected programs were cracked they would be completely stripped of the copy protection system, and transferred onto a standard DOS disk that any normal Apple II DOS copy program could read.
Most of the early software crackers were computer hobbyists who often formed groups that competed against each other in the cracking and spreading of software. Breaking a new copy protection scheme as quickly as possible was often regarded as an opportunity to demonstrate one's technical superiority rather than a possibility of money-making. The cracker groups of the 1980's started to advertise themselves and their skills by attaching animated screens known as crack intros in the software programs they cracked and released. Once the technical competition had expanded from the challenges of cracking to the challenges of creating visually stunning intros, the foundations for a new subculture known as demoscene were established. Demoscene started to separate itself from the illegal "warez scene" during the 1990's and is now regarded as a completely different subculture. Many software crackers have later grown into (extremely) capable software reverse engineers; The deep knowledge of assembly required in order to crack protections enables them - inter alia - to reverse engineer drivers in order to port them from binary-only drivers for Windows to drivers with source code for Linux and other Free operating systems.
Software crackers have their secretive organizations on the Internet. Similar to other "gray area" Internet activities, there are also various detector, legal and other specialists on the subject.
[edit] Industry Response
Apple Computer has begun incorporating a Trusted Platform Module into their Apple Macintosh line of computers, and making use of it in such applications as Rosetta. Parts of the operating system not fully x86-native run through the Rosetta PowerPC binary translator, which in turn requires the Trusted Platform Module for proper operation. (This description applies to the developer preview version, but the mechanism differs in the release version.) Recently, the OSx86 project has been releasing patches to circumvent this mechanism.
Microsoft is planning to reduce common Windows based software cracking with the release of the NGSCB initiative in future versions of their operating system.
