Hiding your source code does not make it secure
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Imagine a heavy iron vault. The owner believes that if the lock mechanism is hidden behind a thick steel plate, a thief cannot pick it. This is a common way to think about software code. If an attacker cannot see how a program works, they cannot find its weaknesses. For years, this was the standard view in corporate boardrooms. It seemed logical to keep the source code—the human-readable instructions that make a program run—under lock and key. This approach is known as security through obscurity.
A False Shield#
The problem with this logic is that it confuses visibility with safety. Hiding the blueprints does not mean the building has no structural flaws. Closed source software contains the same types of mistakes as open source software. Memory leaks and buffer overflows—errors where a program writes data beyond its intended boundary—occur regardless of who can read the code.
Attackers do not need an official copy of the source code to find these holes. They use reverse engineering, which is the process of taking a finished product apart to see how it works. It takes more effort than reading a text file, but a determined adversary has plenty of time and a surprising amount of patience. The result is that closed software often hides bugs from the people who could fix them, while leaving them visible to those who wish to exploit them. Obscurity is not a durable control because it relies on the attacker being ignorant. In security, assuming the enemy is ignorant is a dangerous gamble.
The Maintenance Gap#
The focus on visibility misses the point entirely. The critical factor is not whether the code is open or closed, but whether it is maintained. Maintenance means that a person or an organisation actively looks for bugs and releases patches to fix them. A patch is a small piece of software designed to update a program and resolve a vulnerability.
Modern software is rarely written from scratch. It relies on dependencies, which are external libraries or components created by other people. This creates a hidden chain of trust. If a project uses an old library that no one is watching, a security hole can exist for years without anyone noticing. This risk exists in both open and closed ecosystems. A proprietary product may rely on a forgotten open source component that has not been updated since 2014. The fact that the main product’s code is secret provides no defence against a flaw in a public dependency.
Security researchers and academic experts have long argued that transparency is a benefit rather than a liability. When many eyes look at code, errors are found faster. This is not because open source is inherently perfect, but because it allows for a wider range of analysis. The goal shifts from hiding the lock to making the lock so strong that it does not matter if the thief knows how it works. To recognise this shift is to move away from a strategy of secrets and toward a strategy of resilience.
The real danger is not the person who can read the code, but the piece of code that nobody is reading. An unmaintained dependency is a door left unlocked in a dark alley. It does not matter if the rest of the building is a fortress if the side entrance has been forgotten by the owner.
Check the age and support status of every third-party library in use. Use a software composition analysis tool to find outdated components. Prioritise updates for libraries with known vulnerabilities over the desire to keep internal logic secret.
Frequently asked questions#
What is security through obscurity?
This approach relies on keeping the inner workings of a system secret to prevent attackers from finding vulnerabilities. It assumes that if a flaw is hidden, it remains safe. However, this is a dangerous gamble because determined adversaries can use reverse engineering to uncover weaknesses regardless of whether the source code is public.
Can hackers find bugs in closed source software?
Yes, attackers use reverse engineering to dismantle finished products and understand their logic without needing the original source code. This process takes more effort than reading a text file, but it allows them to identify memory leaks or buffer overflows that the developers might have missed due to a lack of transparency.
Why is software maintenance important for security?
Maintenance ensures that bugs are actively sought and patched before they can be exploited. Since modern software relies on various external dependencies, regular updates are essential. A secret product remains vulnerable if it uses an outdated library with known flaws, making active maintenance more critical than the visibility of the code.