cyberchef
Version:
The Cyber Swiss Army Knife for encryption, encoding, compression and data analysis.
169 lines (145 loc) • 7.56 kB
JavaScript
/**
* @author n1474335 [n1474335@gmail.com]
* @copyright Crown Copyright 2016
* @license Apache-2.0
*/
import Operation from "../Operation.mjs";
import Utils from "../Utils.mjs";
import Dish from "../Dish.mjs";
import MagicLib from "../lib/Magic.mjs";
/**
* Magic operation
*/
class Magic extends Operation {
/**
* Magic constructor
*/
constructor() {
super();
this.name = "Magic";
this.flowControl = true;
this.module = "Default";
this.description = "The Magic operation attempts to detect various properties of the input data and suggests which operations could help to make more sense of it.<br><br><b>Options</b><br><u>Depth:</u> If an operation appears to match the data, it will be run and the result will be analysed further. This argument controls the maximum number of levels of recursion.<br><br><u>Intensive mode:</u> When this is turned on, various operations like XOR, bit rotates, and character encodings are brute-forced to attempt to detect valid data underneath. To improve performance, only the first 100 bytes of the data is brute-forced.<br><br><u>Extensive language support:</u> At each stage, the relative byte frequencies of the data will be compared to average frequencies for a number of languages. The default set consists of ~40 of the most commonly used languages on the Internet. The extensive list consists of 284 languages and can result in many languages matching the data if their byte frequencies are similar.<br><br>Optionally enter a regular expression to match a string you expect to find to filter results (crib).";
this.infoURL = "https://github.com/gchq/CyberChef/wiki/Automatic-detection-of-encoded-data-using-CyberChef-Magic";
this.inputType = "ArrayBuffer";
this.outputType = "JSON";
this.presentType = "html";
this.args = [
{
"name": "Depth",
"type": "number",
"value": 3
},
{
"name": "Intensive mode",
"type": "boolean",
"value": false
},
{
"name": "Extensive language support",
"type": "boolean",
"value": false
},
{
"name": "Crib (known plaintext string or regex)",
"type": "string",
"value": ""
}
];
}
/**
* @param {Object} state - The current state of the recipe.
* @param {number} state.progress - The current position in the recipe.
* @param {Dish} state.dish - The Dish being operated on.
* @param {Operation[]} state.opList - The list of operations in the recipe.
* @returns {Object} The updated state of the recipe.
*/
async run(state) {
const ings = state.opList[state.progress].ingValues,
[depth, intensive, extLang, crib] = ings,
dish = state.dish,
magic = new MagicLib(await dish.get(Dish.ARRAY_BUFFER)),
cribRegex = (crib && crib.length) ? new RegExp(crib, "i") : null;
let options = await magic.speculativeExecution(depth, extLang, intensive, [], false, cribRegex);
// Filter down to results which matched the crib
if (cribRegex) {
options = options.filter(option => option.matchesCrib);
}
// Record the current state for use when presenting
this.state = state;
dish.set(options, Dish.JSON);
return state;
}
/**
* Displays Magic results in HTML for web apps.
*
* @param {JSON} options
* @returns {html}
*/
present(options) {
const currentRecipeConfig = this.state.opList.map(op => op.config);
let output = `<table
class='table table-hover table-sm table-bordered'
style='table-layout: fixed;'>
<tr>
<th>Recipe (click to load)</th>
<th>Result snippet</th>
<th>Properties</th>
</tr>`;
/**
* Returns a CSS colour value based on an integer input.
*
* @param {number} val
* @returns {string}
*/
function chooseColour(val) {
if (val < 3) return "green";
if (val < 5) return "goldenrod";
return "red";
}
options.forEach(option => {
// Construct recipe URL
// Replace this Magic op with the generated recipe
const recipeConfig = currentRecipeConfig.slice(0, this.state.progress)
.concat(option.recipe)
.concat(currentRecipeConfig.slice(this.state.progress + 1)),
recipeURL = "recipe=" + Utils.encodeURIFragment(Utils.generatePrettyRecipe(recipeConfig));
let language = "",
fileType = "",
matchingOps = "",
useful = "";
const entropy = `<span data-toggle="tooltip" data-container="body" title="Shannon Entropy is measured from 0 to 8. High entropy suggests encrypted or compressed data. Normal text is usually around 3.5 to 5.">Entropy: <span style="color: ${chooseColour(option.entropy)}">${option.entropy.toFixed(2)}</span></span>`,
validUTF8 = option.isUTF8 ? "<span data-toggle='tooltip' data-container='body' title='The data could be a valid UTF8 string based on its encoding.'>Valid UTF8</span>\n" : "";
if (option.languageScores[0].probability > 0) {
let likelyLangs = option.languageScores.filter(l => l.probability > 0);
if (likelyLangs.length < 1) likelyLangs = [option.languageScores[0]];
language = "<span data-toggle='tooltip' data-container='body' title='Based on a statistical comparison of the frequency of bytes in various languages. Ordered by likelihood.'>" +
"Possible languages:\n " +
likelyLangs.map(lang => {
return MagicLib.codeToLanguage(lang.lang);
}).join("\n ") +
"</span>\n";
}
if (option.fileType) {
fileType = `<span data-toggle="tooltip" data-container="body" title="Based on the presence of magic bytes.">File type: ${option.fileType.mime} (${option.fileType.ext})</span>\n`;
}
if (option.matchingOps.length) {
matchingOps = `Matching ops: ${[...new Set(option.matchingOps.map(op => op.op))].join(", ")}\n`;
}
if (option.useful) {
useful = "<span data-toggle='tooltip' data-container='body' title='This could be an operation that displays data in a useful way, such as rendering an image.'>Useful op detected</span>\n";
}
output += `<tr>
<td><a href="#${recipeURL}">${Utils.generatePrettyRecipe(option.recipe, true)}</a></td>
<td>${Utils.escapeHtml(Utils.escapeWhitespace(Utils.truncate(option.data, 99)))}</td>
<td>${language}${fileType}${matchingOps}${useful}${validUTF8}${entropy}</td>
</tr>`;
});
output += "</table><script type='application/javascript'>$('[data-toggle=\"tooltip\"]').tooltip()</script>";
if (!options.length) {
output = "Nothing of interest could be detected about the input data.\nHave you tried modifying the operation arguments?";
}
return output;
}
}
export default Magic;