@aikidosec/firewall/helpers/looksLikeASecret.js

Zen by Aikido is an embedded Web Application Firewall that autonomously protects Node.js apps against common and critical attacks

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.looksLikeASecret = looksLikeASecret;
const getFileExtension_1 = require("./getFileExtension");
const LOWERCASE = "abcdefghijklmnopqrstuvwxyz".split("");
const UPPERCASE = LOWERCASE.map((char) => char.toUpperCase());
const NUMBERS = "0123456789".split("");
const SPECIAL = "!#$%^&*|;:<>".split("");
const KNOWN_WORD_SEPARATORS = ["-"];
const WHITE_SPACE = /\s+/;
const MINIMUM_LENGTH = 10;
function looksLikeASecret(str) {
    if (str.length <= MINIMUM_LENGTH) {
        return false;
    }
    const hasNumber = NUMBERS.some((char) => str.includes(char));
    if (!hasNumber) {
        return false;
    }
    const hasLower = LOWERCASE.some((char) => str.includes(char));
    const hasUpper = UPPERCASE.some((char) => str.includes(char));
    const hasSpecial = SPECIAL.some((char) => str.includes(char));
    const charsets = [hasLower, hasUpper, hasSpecial];
    // If the string doesn't have at least 2 different charsets, it's not a secret
    if (charsets.filter((charset) => charset).length < 2) {
        return false;
    }
    // If the string has white space, it's not a secret
    if (WHITE_SPACE.test(str)) {
        return false;
    }
    if (KNOWN_WORD_SEPARATORS.some((separator) => str.includes(separator))) {
        return false;
    }
    // Ignore static assests with random file names, e.g. index.BRaz9DSe.css"
    // The function shouldDiscoverRoutes already checks for this, but it's executed after this function, so the route would already be /asset/:secret
    const extension = (0, getFileExtension_1.getFileExtension)(str);
    if (extension && extension.length > 1 && extension.length < 6) {
        return false;
    }
    // Check uniqueness of characters in a window of 10 characters
    const windowSize = MINIMUM_LENGTH;
    const ratios = [];
    for (let i = 0; i <= str.length - windowSize; i++) {
        const window = str.slice(i, i + windowSize);
        const uniqueChars = new Set(window);
        ratios.push(uniqueChars.size / windowSize);
    }
    const averageRatio = ratios.reduce((sum, ratio) => sum + ratio, 0) / ratios.length;
    return averageRatio > 0.75;
}