webfreeeasy

Rogue Bot (Evaluative)

hackthebox

Task: Compute an 8th-degree polynomial value given coefficients and x. Solution: Submit a Python script to the /run endpoint that evaluates the polynomial using environment variables.

$ ls tags/ techniques/
pythonwebpolynomial
script_submissionpolynomial_evaluation

$ cat /etc/rate-limit

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Rogue Bot (Evaluative) — HackTheBox

Description

The web application presents a task to compute the value of an 8th-degree polynomial: $P(x) = a_0 + a_1 x + a_2 x^2 + a_3 x^3 + a_4 x^4 + a_5 x^5 + a_6 x^6 + a_7 x^7 + a_8 x^8$

Given the coefficients $a_i$ and the value $x$, the solution must be submitted to the server.

Analysis

The application has a /run endpoint that accepts a Python script for execution. The task is to write a script that computes the polynomial value based on the provided input data.

Solution

A Python script was written to accept the coefficients and the value $x$, compute the result, and output it.

#!/usr/bin/env python3

...

$ grep --similar

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