Reverse engineering also called back engineering or backward engineering can help the engineers extract the design of the product from scratch. Reverse engineering or re-engineering is used by businesses to bring various products like biological, chemicals, mechanical products and so on. Businesses use reverse engineering to understand how various components of a product work in tandem to ensure that the product works successfully. Reverse engineering is used by a company when the engineers want to make better products than the existing ones, when they want to learn the inner workings of the product, reconstructing an outdated product or when the engineers want to find out vulnerabilities in the product.
Re-engineering in software engineering is the process of re-engineering the code of software to identify the inner workings of the software. Many top software development companies utilize reverse engineering to build software products. There are many reasons why a software development company might require using reverse engineering. Before we delve into the reasons, we must first understand what exactly software reverse engineering is.
What is software reverse engineering?
Software reverse engineering is the process in which the software engineers recover the design, specifications of requirements and product functions by analyzing the source code of the software. The aim of reverse engineering is to help software engineers understand and improve the mechanics of the software in a better way.
In order to perform reverse engineering, the software engineers need to be proficient in the following skills
- Network monitoring
- Disassembling
- Debugging
- API development and integration
- Knowledge of several programming languages
- Knowledge of compilers
There are many occasions on which software development companies need to use reverse engineering. While there is no other alternative in some cases, reverse engineering proves to be a better alternative than other methods. Whether to use reverse engineering or not depends upon the requirement of the project and the skill level of the software developers.
We have mentioned below some of the most common cases where software reverse engineering is used.
- When the company needs to modernize the software product, the engineers can use reverse engineering to understand the legacy system.
- When there is no documentation available for the product.
- When legacy systems are involved.
- When a company needs to understand the product design of a competitor.
- When a company needs to enhance the security of software by researching the network protocols.
- When the company want to improve compatibility with third-party software
- When the company needs to test the quality of the software
- When the engineers want to detect Trojans, viruses and extortion software
- When the company wants to find out software bugs
Most common Uses of reverse engineering
Software development companies utilize reverse engineering in a wide array of areas. We have mentioned below some major areas where software developers use software reverse engineering.
Improvement of product and process
Most software programs that have APIs designed to allow the third-party software to integrate with the existing software. The issue is that most of the APIs are not good enough and hence the third-party software developers have to reverse-engineer the programs with the software they intend to work with. Reverse engineering aids better compatibility between software.
Cybersecurity
According to IBM, the average cost of a data breach is around $3.92 million. Companies that develop security software commonly reverse engineer various types of malware and viruses to find out how they work. The Cybersecurity analysts pull apart a piece of malware and study the various techniques deployed by the malware developers. Reverse engineering allows cybersecurity experts to develop defenses proactively instead of reacting to every emergency.
Interoperability
Interoperability is a huge problem for software developers. For instance, the software engineers might need to reverse engineer Microsoft Word to run the program on Mac. Reverse engineering helps software developers to improve the interoperability of a program.
Artificial Intelligence
Even the world's most powerful supercomputer cannot match the capabilities of the human brain. Scientists worldwide know this fact and that's why researchers are trying to build AI systems that can mimic the human brain using reverse engineering. Scientists have already achieved considerable success in mimicking the sophisticated AI systems of Google, Amazon, IBM and Microsoft.
Let’s have a look at the major benefits of using software backwards engineering.
Helps find the correct technology
Often, software engineers waste a lot of time researching the suitable tools, components, or technology stack while working with a new domain. Reverse engineering allows the software developers to speed up this stage significantly.
Find out possible project constraints
Reverse engineering can also be used to research project limitations. Sometimes, while developing software, the companies do not think about whether all the features they have planned to include in the software would work as intended or not.
Reverse engineering can help the engineers determine whether it is possible to include all the features as intended originally. Thus, reverse engineering helps companies avoid technology constraints while implementing features. For instance, suppose a company wants to build a mobile app that obtains a list of the available Wi-Fi networks in the vicinity. If the company wants to build this app for iOS, then it might face some issues. This is because while many Android apps have such functionality, there are no iOS apps that have such a thing.
To check whether there might be a privacy restriction in iOS that may prevent the app from accessing the nearby Wi-Fi networks, the engineers can research the permissions required for the iOS system settings app.
Build better product architecture
Building feasible product architecture is one of the most challenging stages of software development. This is because even a small mistake can potentially ruin the entire project. Reverse engineering helps the software developers research the existing solutions and use the knowledge to avoid critical mistakes while developing their software. One of the most important software on any system is antivirus software.
The antivirus software has to keep working round the clock to ensure the safety of the system. Many antiviruses software fail during software updates. Many software developers face a lot of challenges with the update process of antivirus software. If the antivirus software fails during the update process, then the damages can be irreparable. To ensure that the antivirus software keeps running during all circumstances, the software engineers reverse engineer the antivirus software to build their own secure update procedure that does not interrupt the antivirus software's performance.
Integrate third-party libraries easily
Most of the software in operation today needs to integrate with third-party libraries to perform various functions. Integrating third-party code into the software can prove to be difficult if the code is poorly documented.
It becomes challenging for the software developers to detect the reason why a certain library with little or no documentation crashed inside a project. Using reverse engineering, the software developers can find the actual cause of the crash for a particular library. They can then either fix the issue or find a workaround.
Help with legacy systems
Working on legacy systems involves dealing with outdated documentation. Sometimes, the software engineers do not have the source code available to them. This is where reverse engineering helps, as using reverse engineering; the software engineers can obtain and analyze the source code.
Often the software development companies face situations where they need to build new functionality in old software built by someone else. Many times the customers do not have the required documentation of the software which creates problems for the software developers as they do not know the right place to insert the new code. Searching for the legacy code is not a viable option as it can take a lot of time and effort.
The software engineers can instead reverse engineer the existing code and analyze the software’s architecture and internal logic. Through reverse engineering, software developers can find the perfect place to insert the new code.
Also Read: How to identify an ideal software development company for outsourcing IT projects?
Best software reverse engineering tools
Reverse engineering requires a lot of skills, but just good skills are not enough. The software developers will require the assistance of various reverse engineering tools to finish a reverse engineering project effectively.
Here is a list of reverse engineering tools that can help all software reverse engineers.
Disassembler
Disassembler is one of the most important reverse engineering software tools. The disassembler translates executables to assembly code. There are many disassemblers available that help engineers speed up the process of reverse engineering. The disassemblers perform various functions like
Displaying the function call tree
Parsing the import and export of the executable
Showing necessary information about the executable
The disassemblers can also show code in C language, which helps sofware programmers who are not familiar with assembly.
Some of the most popular disassemblers are
HIEW
HIEW is a disassembler that is much more than a hex editor. HIEW allows the software engineers to modify a binary file to support Windows PE EXE formats and Linux ELF.
IDA
The IDA (Interactive Disassembler) is computer software that generates assembly language source code from machine-executable code. The IDA also supports a wide variety of executable formats for different processors and operating systems.
The Reverse Compiler or Decompiler
A reverse compiler or a decompiler is a tool that easily converts the assembly or machine code into a source code for high-level languages like C. The Decompilers also transform intermediate languages like Microsoft Common Runtime Language and Java byte code into source code. Decompilers help the software engineers understand the high-level logic like if-then statements and loops.
JODEJODE is a package that contains a decompiler and an optimizer for java. JODE is an open-source package that reads class files and produces files similar to the original java file. JODE supports all constructs of JDK-1.3, including the anonymous and inner classes.
.NET Reflector
The .NET reflector is one of the best reverse engineering software available for .NET projects.NET reflector acts as a decompiler, class browser and a static analyzer for software built using the .NET Framework. The .NET reflector is used to inspect, browse, search and navigate the contents of a CLI component. .NET reflector translates the binary information into human-readable form.
Debuggers
A debugger is a tool that helps software developers to see how the software behaves at various points.
• WinDBG and OllyDBG are the most popular debuggers available right now.
• While WinDBG features a kernel-level debugging, OllyDBG provides built-in disassembler and API parsing.
The engineers can choose the reverse engineering tools based upon the specific requirements of their project.
Knowledge required for software reverse engineering
To finish a backwards engineering project successfully, the software engineers require knowledge in a wide range of technologies. For instance, software engineers would need to understand the network structure to know in detail about inter-process communication. Network knowledge will also enable the software developers to understand the structure of network packets and the connections along with the order of connections.
Often the software engineers need to reverse engineer the crypto algorithms to crack a code. To successfully decode the crypto algorithms of malware, software developers require a deep understanding of crypto science.
Understanding crypto science involves acquiring deep knowledge about the most popular encryption methods and algorithms they need to deploy. The software engineers who do reverse engineering need knowledge about how the various system components interact with the file they want to decipher. The extensive knowledge about file structures helps the software developers decode files of various file systems and it also helps them understand how files are internally structured.
Knowledge about disassemble is very important as it allows the software engineers to determine the algorithms and logic that the software employs. To find different approaches for various problems, the software engineers need to know about the various types of compiles, disassemblers, file formats, and operating systems.
The software engineers will also require knowledge about the assembler to better understand how the functions are called in particular software and the stack structure. The engineers that reverse engineer a code need to understand the idea behind why a certain part of the code was written instead of trying to guess the original code. This is where the knowledge about compilers helps them.
By knowing how the assembler outputs the code, the engineers can create their own prototype based upon their understanding of the original code. The software engineers, who wish to reverse engineer software, also need to possess knowledge about various programming and the application structures.
What are the processes of Reverse Engineering?
The following are the various processes involved in reverse engineering.
Implementation recovery
The software engineers prepare an initial base for the reverse engineering process. Since the initial base will serve only as the reference, it should only reflect the implementation and no other inferences shall be made.
To prepare an initial base, the software developers need to read through the existing documentation to learn about the software they want to reverse engineer. This exercise helps the software engineers to understand the intent of the people who developed the software.
Going through the documentation helps the software developers notice things when they proceed with the reverse engineering process. The software engineers then enter the database structure into a modeling tool. The software engineers sometimes use tools that can read the system tables and seed a model. While using these tools, the software engineers shall ensure that they skim the database structure to know in detail about the development style.
Design Recovery
The software engineers perform only straightforward actions in the design recovery process and postpone the conjecture and interpretation until the recovery and analysis stage.
During the design recovery process, the software engineers try to resolve the following issues:
Foreign keys
Determining the foreign key references from one table to another is usually the trickiest aspect of design recovery. The software engineers can identify foreign keys by matching the names and data types. While most legacy applications do not have the capability, some database management systems like RDBMS let the developers declare foreign keys.
Identity
It is seen that most of the time, unique indexes will be defined for the candidate keys of the entity types. If they are not, then the software engineers should look for unique combinations of data that can show a candidate key. The software engineers can also infer the candidate keys by considering the names and conventions of style. A suspected foreign key may imply a corresponding candidate key.
Queries
When queries are available, the software engineers can use them to better understand identity and foreign keys.
Analysis recovery
In the analysis recovery process, software developers should think about taking help from application experts.
Analysis recovery consists of four main tasks.
Redundancy
In this task, the software engineers need to remove derived data for wrong reasons. The software engineers might need to examine the data to determine whether a data structure is duplicate or not.
Clarification
The software engineers should remove all non-essential design components. For instance, there is no need for file and database access keys in the analysis model as they are merely design decisions.
Model integration
It is common for software engineers to prepare multiple models from multiple information sources. For instance, software engineers can have a reverse-engineered model by studying structure and data. The software engineers can also prepare a forward-engineered model from a user manual. The final model must fuse any separate models.
Errors
Any database errors must be thoroughly eliminated. This step ensures that the software engineers understand the database thoroughly.
Recovering software source code
A source code of the software is a human-readable text which is converted by the compiler into machine-readable language. A decompiler is used to open the source code by translating it back from machine-readable language into human-readable text. In case the decompiler is unable to reconstruct the code completely, and then a disassembler can be used.
Hence, it is normal for the software engineers to reconstruct partial code, and this isn’t a big problem as the process is more about understanding the code rather than recovering the original code completely. Even partial code can be used to perform analysis of the software and correct errors.
Understanding the communication protocol rules
The software developers also use reverse engineering when they want to write code for operating system drivers, but the information regarding the exact functioning of the operating system is not in the public domain. The software engineers use a sniffer to analyze the data traffic in a network. The sniffer helps the software engineers identify the rules that a corresponding protocol follows. The sniffer also helps the software engineers detect anomalies in data exchange between two devices.
Is it legal to reverse engineer software?
Many software developers think that reverse engineering software is illegal. There is no law against reverse engineering and the practice of reverse engineering in itself is perfectly legal. The Economic Espionage Act of the U.S.A does not explicitly forbid reverse engineering, but still there are a few ethical concerns regarding the practice as many hackers also use reverse engineering to find loopholes in the system.
The following U.S. laws are applicable on the process of reverse engineering
- Anti-circumvention provisions listed in the Digital Millennium Copyright Act (DMCA)
- Trade secret law
- Contract law
- Copyright and fair use law
- The Electronic Communications Privacy Act (ECPA)
The copyright law is the biggest obstacle for people practicing reverse engineering as most software products in the IT domain are treated as intellectual property. Software engineers can get themselves into trouble even if they do not actually use the original code. While reverse engineering, the software developers should ensure that the lessons they learned from reverse engineering the code should constitute the use of protected trade secrets or the law might consider them as a violation of the contract.
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The law is not clear in many cases. For instance, the DMCA prohibits the use of reverse engineering to circumvent technological protection measures. Many experts think this clause bans techniques like code obfuscation, protocol encryption, authentication handshakes and code signing. ECPA is another U.S. act that prohibits software companies from intercepting electronic communications flowing over a network. Hence unless consent is obtained from the relevant parties, any reverse engineering of packets could lead to a violation of the ECPA.
Think reverse to go forward
Reverse engineering helps the software developers gain helpful information and helps improve the security of the software. Reverse engineering requires a good deal of programming experience and a varied skill set. Software engineers need to be careful not to break the copyright laws or harm their software.
At Prismetric, we are the leading software development company in the industry. We have over a decade of experience in delivering high quality IT products to our clients located worldwide. We have a talented and experienced team of software developers who can cater to any requirement. Please feel free to contact us for any reverse-engineering requirement, we would be more than happy to help.