Security is the current hot topic, whether it pertains to a person’s house, country, website, or smartphone. I’m specifically referring to the smartphone sector, which is overrun with apps. The primary focus of app developers is ensuring the safety of their mobile applications, especially to guard against reverse engineering.
What is mobile application reverse engineering?
A mobile application, particularly one for Android, can now be cracked relatively easily thanks to technological improvements. The hacker has the ability to block advertising and even disconnect the device from different verification services.
Some people could want to “crack” the application (device, program, or software) in order to learn how it functions and what particular features it has; either to create an app that is superior to yours or to entirely duplicate it.
Reverse engineering, the term for this specific activity, is used widely in manufacturing but even in military jargon.
The APK file’s source code and other resources are extracted using reverse engineering techniques. The process of decompiling any APK file is not that difficult. To obtain the app source code, it is necessary to convert dex files into jar files, which must then be converted into java source code. Many helpful tools are available, including Apktool, dex2jar, JD-GUI, and JAD.
To prevent mobile applications from being reverse engineered, it is crucial to guarantee the greatest level of security.
How to protect app from reverse engineering by adhering to the following advice, one can make it challenging to hack the mobile app:
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ProGuard Support
This is a Java-based, open-source utility that aids in ensuring the security of mobile applications. It is a control utility that pre-verifies, compresses, optimizes, and obfuscates the code. Let’s examine how it operates:
Shrink Method: Identify and delete any unnecessary classes, fields, or method properties from the mobile app.
Analysis and optimization of the bytecode for various techniques.
Obfuscation: The remaining classes, fields, & methods are given brief, meaningless names.
By making the source significantly smaller, more complex, and efficient, the aforementioned processes make it challenging to reverse engineering an application.
Pre-verification: This procedure entails adding pre-verification data to classes that JME, Java 6 or higher, mandates.
Deobfuscators like APK De-Guard are available to prevent obfuscation. It makes use of machine learning, making it among the most precise and effective deobfuscators.
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Save significant sections of code to the server:
Removing the code from the application and moving it to any online service that would be encrypted server-side language is another method of protecting applications.
For instance, if a business uses a special technique or code for its application, it would not permit its code to be stolen. They can avoid this by simply changing their algorithm or code, allowing the data to be processed on a distant server, and then accessing the data via the application.
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Write crucial codes in C/C++:
Java-written code is simpler to decompile than C/C++-written code. As a result, programmers occasionally use NDK to write important portions of your code natively into the.so files. These files are also added as a built library. Even while this code may be broken down into assembly language, doing reverse engineering on such a large library can be laborious and time-consuming.
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Use caution when using SSL: To improve the security of their code, developers employ SSL when communicating with servers and devices.
The class that implements the SSLSocketFactory interface has a number of unnecessary methods. Due to the fact that these simple techniques allow all types of certificates, the application is susceptible to middle-layer assaults (MitM). Data sent using the SSL/TSL protocol may no longer be secret as a result of this.
By only supplying a self-signed certificate, an attacker can quickly break the connection and obtain vital data.
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Steer clear of keeping data in raw format:
The raw format should not be used to store values. Let’s say it’s necessary to record the value of a user’s balance (in money); in such case, the values must be maintained in encoded form.
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Securing User Credentials: In order to prevent reverse engineering of the program, it is advisable to safeguard the user credentials.
Less frequently should the mobile application ask for user credentials. This will enable the apps to prevent phishing assaults, which are more likely to fail. Utilizing an authorization token is advised.
It is not advisable to keep the login and password on the device. Use a temporary authorization token and finish the initial authorization process.
Use a password object that holds user sign-in information in certain circumstances.
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Hide API keys:
Third-party service providers typically utilize an API key to authorize access to resources. They frequently employ it to generate income from their data. It is advised against saving the API keys as hardcoded Java code, shared files, resource folders, or preferences. This is so that the key can be accessed by simply unzipping them and decompiling the API. To safeguard the API key, either use NDK or private/public key exchange.
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Hashing formula
The majority of hash functions, including MD2, MD5, and SHA1, are weak and open to attack. Confidentiality can be readily compromised if they have been used to access data like passwords or other vital information. Use secure methods instead, such SHA-2.
A typical hash function needs to be slow.
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Insecure use of reflection
It is capable of running harmful code at random. Typically, the input used by the method that implements the reflection function comes from an unreliable source. This makes it easier for attackers to manipulate the application’s control flow graph, giving them access to different constraints and circumventing authentication processes.
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Aim to avoid utilizing external storage
All apps can access files that are saved on external storage devices. Every time a user connects a Storage media device to a computer, they are simple to change.
The files are still present on the external storage even if the application is deleted. It might lead to the secrecy of important data being compromised.
