DR. MIGUEL ÁNGEL OROS HERNÁNDEZ 8. Cracking

Cracking Magnitude of piracy  All kinds of digital content (music, software, movies)  Huge economic repercussions Cracking  Process of attacking a copy protection technology  One kind of reversing  Modification of an application’s binary to cause or prevent a specific key branch in the program’s execution

Cracking 1. Piratería y protección de copias 2. Tipos de protección 3. Conceptos avanzados de protección 4. Marca de agua

Piratería y protección de copias

Applying reverse engineering until the software cracker reaches the subroutine that containts the primary method of protecting the software Elimination of the expiration period from a time-limited trial of an application Scanning for the use of a commercial copy protection application (CD, DVD)  CloneCD  Alcohol 120%  Game Jackal  Daemon Tools

Piratería y protección de copias The open architecture of today’s personal computers makes impossible to create an uncrackable copy protection technology

Piratería y protección de copias Class break Problem in practically every copy protection technology Takes place when a security technology or product fails in a way that affects every user of that technology or product, and not just the specific system that is under attack Huge efforts of developers of copy protection technologies Problem Publishing the results of defeating the protection mechanism

Piratería y protección de copias copy protection mechanism Definition A delicate component Invisible to legitimate users Design considerations Resistance to Attack End-User Transparency Flexibility

Tipos de protección

Media-Based Protections  The primary copy protection approach in the 1980s  Idea: have a program check the media with which it is shipped and confirm that it is an original  Floppy disks: creating special “bad” sectors  Programs:  CopyWrite  Transcopy  Are they legals? Serial numbers  Idea: the software vendor ships each copy of the software with a unique serial number printed somewhere on the product package or on the media itself  The installation requires this number  If the program is installed, the user is registered  When the user contact customer support, the software vendor can verify that the user has a valid installation of the product

Tipos de protección Challenge response and online activations The program sends a challenge response (an protocol used for authenticating specific users or computers in networks) Idea: the both parties share a secret key that is known only to them Improvement to the serial number Challenge response Vendor’s approval Crackable: create a keygen program that emulates the server´s challegne mechanism and generate a valid response on demand

Tipos de protección keygen A license or product key generator (sometimes stylized as keygen) is a computer program that generates a product licensing key, serial number, or some other registration information necessary to activate for use a software applicationproduct licensing keyserial numbersoftware

Tipos de protección Hardware-based protections Idea: add a tamper- proof, non-software- based component into the mix assists in authenticating the running software Use of attached chip to the computer like USB

Conceptos avanzados de protección

Cripto-Processors A well-known software copy protection approach ProposedRobert M. Best Idea: design a microprocessor that can directly executed encrypted code by decrypting it on the fly Hard to crack because the decrypted code would never be accessible to attackers Digital Rights Management DRM Models  Encrypting the protect content  Try their best to hide the decryption key and control the path in which content flows after it has been decrypted

Conceptos avanzados de protección Digital Rights Management The Windows Media Rights Manager  Idea: separate the media from the licence file (encryption key required to decrypt and playback the media file) Digital Rights Management Secure Audio Path  Attempts to control the flow of copyrighted, unencrypted audio within Windows  Problem: anyone can write a simulated audio device driver that would just steal the decrypted content while the media playback software is sending it to the sound card

Marca de agua

Watermaking  Processing to adding an additional “channel” of imperceptible data alongside a visible stream of data  Invisble (or inaudible) data stream that is hidden within the file Properties  Difficult to remove  It contains as much information as possible  Imperceptible  Difficult to detect  Encrypted  Robust

Marca de agua aplicaciones Enabling authors to embed indentifying information in their intellectual property Identifying the specific owner of an individual copy by using a watermarked fingerprint Identifying the original,unmodified data through a validation mark

Bibliografía Reversing: Secrets of Reverse Engineering  Eldad Eilam  Wiley Publishing, Inc.  2005

Fin