Introduction

Rust is a programming language created in 2015 by a small team of people, and later adopted by Mozilla.

It is a compiled low-level language, which aims to be as fast as C or C++, while incorporating some features from high-level languages such as Go, Python, or JavaScript.

Rust has three main goals:

• Performance
• Safety
• Productivity

Performance

Rust aims to achieve performance similar to C or C++.

Rust is statically typed, which means the data type of a variable is known at compile time. This allows the compiler to optimize the code further than if we didn’t know the types.

Rust does not use garbage collection (despite being a low-level programming language). Garbage collection is where the program attempts to reclaim memory from objects no longer in use by the program.

Unlike languages like Python and JavaScript, Rust avoids these abstractions to minimize issues, making it a preferred choice for low-level programming.

Safety

Rust is designed to be completely memory safe. This means that memory-related exploits aren’t possible in Rust, unless you explicitly specify unsafe Rust code.

The Microsoft Security Response Centre reports that 70% of all CVEs assigned are memory safety issues. Microsoft states:

“This means that if that software had been written in Rust, 70% of these security issues would most likely have been eliminated. And we’re not the only company to have reported such findings.”

Rust provides tools to wrap unsafe actions, enabling static enforcement of unsafe code by the Rust compiler.

The memory safety is guaranteed by the concept of ownership, governed by these rules:

• Each value has a variable, called an owner.
• There can only be one owner at a time.
• When the owner goes out of scope, the value will be dropped.

Values can be moved or borrowed between variables, but no value can have more than one owner.

Consider an example in Python:z

squares = (val * val for val in range(100))
print(min(squares))
print(max(squares))

What we want is:

0
9801

But what we get is:

>>> print(min(squares))
0
>>> print(max(squares))
Traceback (most recent call last):
  File "", line 1, in 
ValueError: max() arg is an empty sequence

This is because min alters the variable squares. It’s strange, because we just wanted the minimum — not to alter the whole variable!

In Rust, the same code is:

fn main()
   let squares = (0..100).map(|val| val * val);
   println!("{:?}", squares.min());
   println!("{:?}", squares.max());
}

When we try to compile this, Rust tells us:

error[E0382]: use of moved value: `squares`
 --> ownership.rs:4:21
  |
3 |    println!("{:?}", squares.min());
  |                     ------- value moved here
4 |    println!("{:?}", squares.max());
  |                     ^^^^^^^ value used here after move
  |
  = note: move occurs because `squares` has type `std::iter::Map<std::ops::Range, [closure@ownership.rs:2:31: 2:40]>`, which does not implement the `Copy` trait

The important part here is that Python allows functions to alter variables they do not own, whereas Rust doesn’t.

Productivity

Rust’s third major goal is productivity, and it provides a rich set of tools to support developers.

With these tools at your disposal, compiling a Rust program and encountering bugs is incredibly rare. The tooling and language usually catch issues long before you hit the compile button.

Conclusion

If you are seeking exceptional speed, memory safety, and enhanced productivity, Rust is the language you’ve been looking for.

As Pentesters, part of our job is to provide solutions to developers. While suggesting a low-level language like Rust to Python developers might seem unconventional initially, Rust offers robust support, even allowing calls from functions written in other languages through foreign function interfacing.

We can leverage Rust to rewrite security or performance-critical code that seamlessly integrates with our existing codebase.

Here’s an example of calling C code:

extern "C" {
    fn abs(input: i32) -> i32;
}

fn main() {
    unsafe {
        println!("C believes that the absolute value of -3 is: {}", abs(-3));
    }
}