When software behaves in an unexpected manner or crashes without any external factors, it's time to do some debugging. Debugging is the process of revealing and resolving errors and issues, called ''bugs'', within software, systems, mobile applications, and other.
It is an exceptionally demanding task, requiring focus and a great amount of patience. In some cases, debugging takes more time than coding a program from scratch. Why is that so? Well, with complex software structures, one component is dependent on another component, or even a couple of them. That means that a bug in a single component indirectly affects numerous other lines of code that need to be revisited and adjusted accordingly.
To aid them in the debugging process, programmers use debuggers. A debugger is a tool that enables you to view the application code while it is running. You can stop the execution of the program, analyze variable values, execute the program in steps (line after line), set breakpoints on specific lines which stop the execution, and more. This detailed view of the code in its running mode enables you to understand flows and application logic, as well as to detect errors within the code.
Upon detecting an issue causing the application to run in an unexpected manner, the debugging process goes as follows:
Reacting on the basis of a problem description often results in an issue greater than the one you started with. Fixing a single line of code might affect other functionalities that are not obvious at first. Make sure that you are able to reproduce the bug and save yourself from the trouble of revisiting the code all over again.
More information means narrowing down the error area, as well as eliminating additional issues arising from the bug fix.
Help yourself and use a debugger to aid you in the debugging process.
Capture the program when the bug appears. Make sure to get all of the variable values and states at the spot.
Based on the snapshot, analyze the values and try to reveal the cause of the issue.
Fix the bug and make sure that your bug fix does not affect any other lines of code, resulting in a new bug.
There are a couple of debugging approaches, and here are the most popular ones adopted by developers:
Despite the general inefficiency and low success rates, debugging by brute force is the most popular method among programmers. According to O'Riley, there are at least three categories when discussing the brute force method; debugging with a storage dump, debugging according to the common suggestion to ''scatter print statements throughout your program'', and debugging with automated debugging tools.
This approach is based on deduction. Your starting point is where the program showcases the incorrect result. From there, you build your solution backward in order to reveal which variables are causing the trouble.
A number of hypotheses are developed in connection to the occurring bug, followed by creating a list of possible causes. This is followed by testing each of the listed possible causes and, finally, the elimination process. Another name for the cause elimination method is the induction and deduction method.
Program slicing is based on taking a group of program statements and testing conditions at a particular point of interest. It is a simplified and less time-consuming approach to debugging.
From the above introduction to debugging and debuggers, by now, you should be able to see how there's also room for malicious practices. Debugging and debuggers enable the user to get insight into the application logic. If someone with bad intentions and a sufficient amount of programming knowledge decides to misuse a mobile application, they can easily use debuggers to achieve their goals.
Debuggers come in handy when practicing reverse engineering. In terms of software and cybersecurity, reverse engineering is the process of disassembling a piece of software, followed by a thorough analysis of its functions and logic in order to fully understand its behavior.
You can see how things can go south when a person with malicious intentions, the right tools, and enough knowledge decides to tamper with an app. Debugging allows you to see the app from the inside understand application logic and flows. This knowledge assists the attacker with designing an imitation app containing a piece of malicious code. From there, there is a number of possibilities to tamper with the app, from individual attacks to data breaches.
What's also of interest for the attacker are the logging levels. Debuggers provide insight into debug log levels containing information necessary for diagnosing issues, troubleshooting, or running an application in the test environment. It contains more granular information, the kind you wouldn't need in the usual production environment. By providing detailed diagnostic information about the application flows and logic, debug log level can prove to be a very useful resource for an attacker.
Although the initial idea of debuggers is a safe haven when fixing occurring bugs, malicious use has been around for quite a while. When talking about mobile application security, App Protector is a safe haven that safeguards your app from various types of threats, including debuggers. By integrating App Protector into your mobile application's runtime environment, you are ensuring detection and prevention of the following threats:
If an anomaly in the application's behavior is detected, App Protector responds in one out of three ways:
By implementing App Protector, the look and feel of the original mobile application remain intact. However, the security levels are significantly increased, protecting your application and its end-users.
In case you're curious, feel free to contact us - zero obligation. Our ASEE team will be happy to hear you out.