Because the code in Android apps is not rendered into machine code, it is always vulnerable to extraction and reverse engineering. The vulnerable code can then be used for a variety of purposes, which could be intimidating for any serious mobile app business, including:
Using the code for one’s gain
Look for flaws in the code
Look for sensitive data that has been hardcoded into the code.
Malware catching
Adding new features to an existing application
1)Malwares such as spyware, trojans, and ad-wares pose serious threats to Android apps. Although some malware is not intended to cause harm, some can cause unexpected and undesirable problems such as localized denial of service, abnormal battery drain, and so on. Furthermore, malware such as Spywares can gain access to a smartphone’s camera or microphone module and send data back to the attackers. Adware is a type of malware that uses existing communication channels such as Email, Instant Messaging, MMS, Bluetooth, and SMS to send harmful advertisements to a specific number of people.
Security risks associated with code decompiling in Android.
Security is even more of a concern in Enterprise Mobile application development because most apps are data-heavy, such as Financial apps or Healthcare apps.
How to Avoid Android App Decompilation to Prevent Reverse Engineering
We saw in the preceding section how simple it is to decompile an Android app.
. It will then be possible to extract the source code of an app. Many tools are available for reverse-engineering an Android app, including dex2jar, Apktool, JD-GUI, JAD, and others.
However, by paying attention to a few details, it is still possible to prevent reverse engineering of Android apps.
These ways are really helpful for the protection of app from reverse engineering:
1) Place critical code on a server.
You can use remote procedure calls to a secure server. This reduces the possibility of your codes being stolen because the code is always stored on the server and only the results are visible. However, if your app is going to be used by a large number of people (millions), you will need a large server farm.
A server farm is an expensive investment that is not always a viable option. Furthermore, in the case of poor network connectivity, it renders your code fragile and adds to your users’ frustration.
The cost of complete code security is high, but the good news is that you probably won’t need it. A better solution is to keep the code you don’t want to leak in hardware under your control.
2) Debugger Detection Methods
There are some other inventive ways to protect your code from decompilation. They entail using debugger detection techniques to prevent run-time analysis and combining them with encryption of portions of binary codes. However, any determined attacker can find a way around it. If you want to learn more about a specific debugger detection technique, visit the OpenRCE Anti Reverse Engineering Techniques Database. It analyses and describes various anti-debugging, disassembly, and dumping techniques.
3) Parts of C/C++
You can also write the key parts of your code in C/C++ and include them as a compiled library. While it is possible to disassemble it into assembly code, reverse engineering a large library from assembly takes a long time. In comparison to C/C++, Java is easier to decompile.
4) write files directly into. so files.
NDK allows you to write the files natively. so files, which are far less likely to be decompiled than APKs. There are a few good decompilers available, but the attacker would need to be knowledgeable about ARM processor architecture, assembler language, JNI conventions, and compiler ABI. You’re causing the skilled attacker a few sleepless nights.
5) Encrypt values when storing them on mobile devices.
When storing values on the device, avoid storing them in raw format to protect your app’s resources. Store them as an algorithm, for example, 50 reward points in your app could be (x*(x2 + 1 – Neutralising factor))/(x+1). You must, however, optimize your algorithm so that you do not end up compromising when rounding up values.
6) Add multi-factor security
It is critical to prevent the attacker from gaining access to the user’s device itself. You can also make it difficult for attackers by implementing multi-factor security, which remembers information about the devices and provides additional channels for detecting a login attempt from an unfamiliar device.
Some even recommend using tools like HoseDex2Jar, but they are very easy to defeat. Tools such as apk tools work perfectly with these APKs.
7) Exercise caution when implementing SSL.
SSL certificates are frequently used by developers to improve the security of their code on the server. On Android, this is frequently accomplished by defining several methods in a class that implements the SSLSocketFactory interface. One issue with these methods is that they can accept any type of certificate, making Android code vulnerable to middle attacks (MitM).
8) Make use of hash functions like PBKDF2, bcrypt, and scrypt.
On Android, the majority of hash functions, such as MD2, MD5, and SHA1, are insecure and vulnerable to malware attacks. However, if they are used to store sensitive information, security can be easily jeopardized. Use secure functions such as SHA-2 instead. A typical hash function should be collision-resistant and not too fast. Exhaustive search complicates the attack if the hash function is too fast.
These are some of the ways by which one can know how to protect app from reverse engineering.
AppSealing’s Runtime Application Self Protection (RASP) provides runtime app protection through binary protection, anti-debugging, and anti-decompilation. The hash validation of all the app’s components and modules ensures a stable environment and integrity protection.
Appsealing detects rooted devices and Android emulators accessing an app and prevents it from being launched to “sanitize” its use. This no-code approach has little impact on memory usage, CPU performance, or battery life. Simply upload the APK, and your app will have a comprehensive security layer in place within 10 minutes.