In this digital world, people use mobile apps for a wide range of purposes, from transfer of funds to investments, order food and groceries online etc. Security of mobile applications is one of the most prominent concerns. According to the study, 35% of communications over mobile phones are unencrypted. This shows that more than one third of data transmitted by mobile devices is exposed to threat.
The Android operating system has many built-in security features like application sandboxing, protection against buffer and integer overflow attacks and segregated memory areas for program instructions and data. When you develop a complex app, it is your responsibility to make it secure and protect the privacy of your users. Organizations should protect their apps while enjoying the benefits that these apps provide. Here we discuss the android app security best practices to refer while building your mobile applications.
You should also know the considerations to build mobile app at- 7 Important considerations when building a mobile app
So as to keep the native code secure, android app developers should use android SDK for mobile app development, instead of Android NDK. Whenever you collaborate with one of the developers, ensure that experts use Android SDK. When the native code is integrated during the development process, app receives data over the network. This can come from files or an IPC, that might be exposed to security factors. Hence you should secure the native code by using Android SDK during the development process.
All communication between your app and servers must be over HTTPS connection, mostly using the HttpsURLConnection class. Many android users connect to several open Wi-Fi hotspots in public areas every day. Some of those hotspots could be malicious and malicious hotspot can easily change the contents of HTTP traffic to make your app behave in an unexpected manner or worse still, inject ads or exploits into it.
Using HTTPS, as long as the server is configured with a certificate given by a trusted certificate authority, like DigiCert or GlobalSign, you can be certain that your network traffic is secure against attacks. If app has huge networking code and you are anxious about the possibility that you may accidentally be sending some data as cleartext, you should consider using nogotofail, an open source tool built by Google to find such mistakes.
Sensitive data that is transmitted from client to server should be protected against privacy leaks and data theft. If you lose a device, or it gets stolen, the whole application containing business data should be deleted. This ensures that important data does not go to the wrong hands. Selective removal of data enables the IT department or users to wipe off the company data in devices. It is recommended that use either an SSL or VPN tunnel, which ensures that user data is protected with strict security measures.
Internal storage capacity of android devices is generally limited. So, you you may have no option except to store sensitive data on external storage media, like, a removable SD card. As the data on external storage media can be directly accessed by both users and other apps on device, it is important to store it in an encrypted format. Most popular encryption algorithms among developers is AES(Advanced Encryption Standard), with a key size of 256 bits. Writing a code to encrypt and decrypt your app’s data using package javax.crypto that is included in Android SDK can be confusing. So mostly developers prefer use of third-party libraries like Facebook’s Conceal library, that are usually easy to work with.
A while ago when GCM(Google Cloud Messaging), didn’t exist, many developers were using SMS to push data from their servers to their applications. But now, this practice is largely gone. If you still doesn’t switch from SMS to GCM, you must know that SMS protocol is neither encrypted nor safe against spoofing attacks. Also, SMS can be read by any app on the user’s device that has the READ_SMS permission. GCM is more safe and is best way to push messages to an app because all GCM communications are encrypted. They are authenticated using consistently refreshed registration tokens on the client side and a unique API key on the server side.
When you use third-party libraries, be careful and test code thoroughly before using it in your app. However valuable as they are, some libraries can be extremely insecure for your application. The GNU C Library, for example, had a security flaw that could allow attackers to remotely execute malicious code and crash a system. And, this vulnerability went unseen for more than seven years. Developers should use controlled internal repositories and exercise policy controls during acquisition to protect their apps from vulnerabilities in libraries.
APIs that are not authorized and are loosely coded can grant a hacker privilege that can be misused gravely. For instance, getting authorization information locally helps programmers to easily reuse that information when making API calls. It eases programmers life by simplifying the use of APIs. Also it gives hackers a loophole through which they can hijack privileges. Specialists suggest that APIs be authorized centrally for more security.
In the android app development process, source code should be protected. So developers should make it unintelligible for both decompilers and humans. During compilation, the entire operation must be preserved. Obfuscation process gives a code that is impenetrable. It uses the level of confidentiality for the intellectual assets and prevents reverse engineering. All the while, it improves the security of the Android application.
These days, server remains vulnerable to hackers. Mostly they try to attack the API of the server. This shows that you have to keep the server and API secure to keep away attacks. You can add a firewall for web apps or take code reviews that will help you to deal with this challenge.
With android, invalid user input doesn’t generally makes security issues like buffer overruns. But, if you allow users to interact with SQLite database or a content provider internally uses a SQLite database, you should rigorously sanitize user input or use parameterized queries. It you failed to do so makes your data vulnerable to SQL injection attacks. Similarly, sanitization and user input validation is also important, when you’re using user input to dynamically generate code to run on an embedded scripting engine.
As a part of the AES (Advanced Encryption Standard), the encryption key should be of at least 128 bits. Reputed application developers use the pinning certificate and the hash key to support the security. It incorporates the returning of the complete request, that appears as a hashed string with a secret key. This string is compared by the server with request that it gets, verifying any modification or change in the process.
Most of the security issues are due to issues during the development and configuration of android apps. For this,