How to Brute‑Force Account‑Password Pairs in Python with Simple Nested Loops

Introduction

In a recent Python discussion a user asked how to test every username against every password from two separate files.

Problem Description

The task is to brute‑force two credential files, trying each username with all passwords and vice‑versa, without needing to repeat the opposite direction.

Solution

A simple double‑loop implementation can enumerate all combinations regardless of file length mismatches.

Sample Code

pw = [1,2,3,4,5]
user = ['a','b','c']
for i in user:
    for j in pw:
        print(i, j)

Result

The script prints every username‑password pair, as shown in the following screenshot.

Conclusion

The double‑loop method works even when the two files have different numbers of lines, ensuring all possible credential combinations are tested.