Where Do I Find The Update URL For Google Chrome Extensions?

Question

how can i make the captcha image produced by this script indententer code hereed or italic or twisted like?

<?php
session_start();
$captchanumber = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890abcdefghijklmnopqrstuvwxyz';
$captchanumber = substr(str_shuffle($captchanumber), 0, 5);
$_SESSION["code"]=$captchanumber;
$im = imagecreatetruecolor(50, 24);
$bg = imagecolorallocate($im, 22, 86, 165); //background color blue
$fg = imagecolorallocate($im, 255, 255, 255);//text color white
imagefill($im, 0, 0, $bg);
imagestring($im, 5,5,5,  $captchanumber, $fg);
header("Cache-Control: no-cache, must-revalidate");
header('Content-type: image/png');
imagepng($im);
imagedestroy($im);
?>

Solution 1

I can't help you with group-policy, but each extension includes its update URL in manifest.json.

So, for the current version of adblock (id: gighmmpiobklfepjocnamgkkbiglidom):

%USERPROFILE%\AppData\Local\Google\Chrome\User Data\Default\Extensions\gighmmpiobklfepjocnamgkkbiglidom\2.5.14_0\manifest.json

Contains:

"update_url": "http://clients2.google.com/service/update2/crx"

The extension will query that URL for updates, as per the documentation.

We can therefore construct a URL that will return the update XML from the above URL (just change the ID as needed) - for adblock:

http://clients2.google.com/service/update2/crx?response=updatecheck&x=id%3Dgighmmpiobklfepjocnamgkkbiglidom%26uc

The XML that is returned reads:

<?xml version="1.0" encoding="UTF-8"?>
<gupdate xmlns="http://www.google.com/update2/response" protocol="2.0" server="prod">
    <daystart elapsed_seconds="49387"/>
    <app appid="gighmmpiobklfepjocnamgkkbiglidom" status="ok">
        <updatecheck codebase="http://clients2.googleusercontent.com/crx/download/OAAAAFpzXu4buuGNADfzIKiz34SLARZdBLiXQ2zo50sAlzoBpEz77foH-XT3yHpPureXtHcQSYU2z4ZNstiuKJi-LD8AxlKa5VgufvySdIb5b9U333P0upRk1YPb/extension_2_5_14.crx" hash="" size="529317" status="ok" version="2.5.14"/>
    </app>
</gupdate>

We are interested in the codebase attribute of updatecheck, which provides us the direct URL to the latest CRX file.

Solution 2

The accepted answer is right. To save you the hassle of searching on Linux, the folder is at

~/.config/chromium/Default/Extensions/

Comments

[Sebastien Lorber]

Hi, thanks for this update url, but it looks a bit like retro-engeenering. Do you know if there is any specification for creating a custom entreprise update url endpoint? The linked documentation does not seem related anymore and I can't find anything online on this subject :(