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Maltese developer reveals vulnerability in Google Chrome security

A Maltese software developer has described how he created a plugin for the Google Chrome browser that can watch users’ login information and send that information to him via email.

Andreas Grech used jQuery to write quickcode for the plugin and has been demonstrating the attack as a proof of concept. Writing in a blog, he said he he had tested his system against Facebook, Gmail, and Twitter.

Mr Grech explained how Google Chrome allowed the installation of third-party extensions that were used to extend the browser to add new features. The extensions were written in JavaScript and HTML and allowed manipulation of the DOM, amongst other features.

By allowing access to the DOM, an attacker could thus read form fields…including username and password fields.

"The extension I present here is very simple. Whenever a user submits a form, it tries to capture the username and password fields, sends me an email via an Ajax call to a script with these login details along with the url and then proceeds to submit the form normally as to avoid detection."

Mr Grech stressed that he had not stolen any Twitter, Facebook or Gmail accounts.

"In fact, I didn't even upload this extension to the Google Chrome repository. I have only tried this extension on myself, just to test and see if it works."

See Mr Grech's comments on

http://blog.dreasgrech.com/2010/07/stealing-login-details-with-google.html

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Christian Sciberras

Aug 3rd 2010, 14:54

No, just realistic people. Andreas' post is akin to someone claiming to have made a virus....when people can (nowadays) create virii at the click of a button.

Please be realistic!

Andreas Grech

Jul 15th 2010, 16:21

@A. Cortis:

Yes, installing a malicious ActiveX component in IE can have the same results but the point of the post was not to specifically target Google Chrome and not other browsers. I chose to work with Google Chrome because it has been allegedly dubbed as 'the safest browser' and so I thought it would be interesting to try this experiment on it.

As regards an individual not noting about the data leaks, take a look at this article: http://news.netcraft.com/archives/2010/07/15/firefox-security-test-add-on-was-backdoored.html
Just recently, a Mozilla Security Testing add-on was discovered to have had a backdoor which intercepted login details which were sent to the author of the add-on. Mozilla have said that this add-on has been downloaded ~1800 times and that it still had 334 active daily users (http://blog.mozilla.com/addons/2010/07/13/add-on-security-announcement/). So, as you can see, it's really not that difficult to distribute such malicious add-ons. Keep in mind that such malicious code is usually hidden deep within the add-on as to avoid detection.

With that said, I hope you now see how important it still is to remind people about the dangers of installing 3rd party applications on their computers.

Andreas Grech

Jul 15th 2010, 16:34

The correct link of the Mozilla blog post is: http://blog.mozilla.com/addons/2010/07/13/add-on-security-announcement/

In my previous reply, it has been incorrectly hyperlinked with the adjacent bracket and period :/

Andreas Grech

Jul 15th 2010, 16:22

@Daniel Vassallo

Yes, the timing of such a discovery is perfect.

Here's another post that discusses this discovery: http://news.netcraft.com/archives/2010/07/15/firefox-security-test-add-on-was-backdoored.html

Daniel Vassallo

Jul 15th 2010, 22:03

The fact that the rogue Mozilla Sniffer Add-On was allowed to modify the code of the well-trusted Tamper Data Add-On is definitely a vulnerability in their plugin model. I wonder if that can happen in Chrome.

Darren Mizzi

Jul 15th 2010, 07:54



Andreas's point was to reprove and show again (especially to those who are not aquainted with such things) of the security implications.

Hence everyone is right in saying that this is no vulnerability. Had the article been about security and to prove such risks this code would be used then there would have been no issue - but to imply that a maltese developer revealed a vulnerabiliy in Google Chrome Security when all he did was showing how an existing known issue can be exploited is not correct. As a result the negative comments. I am more than sure that all the people want to be aware of security :)

Andreas Grech

Jul 14th 2010, 13:48

@Darren:

In my post, I have never stated that this is a vulnerability.

As regards not being accepted to the local repository, take a look at this Mozilla blog article: http://blog.mozilla.com/addons/2010/07/13/add-on-security-announcement/

An add-on has been found in their repository which has affected hundreds of users. They clearly state that "Unreviewed add-ons are scanned for known viruses, trojans, and other malware, but some types of malicious behavior can only be detected in a code review."

So if this technique is embedded in a fully-fledged extension that constantly sends requests, it won't be so easy to spot; and when it does get detected, maybe it could have already affected people: "Mozilla Sniffer has been downloaded approximately 1,800 times since its submission and currently reports 334 active daily users. "

Andreas Grech

Jul 14th 2010, 13:50

@Mike:

Thanks for your comment.

At least some people have understood the point of my post.

Christian Sciberras

Jul 14th 2010, 08:36

It's not whining, it's being realistic. This is no such jQuery flaw, for your information, if someone executes some javascript, it doesn't require jQuery, at all.

As a comparison, I can boast I've found a new vulnerability in all existing browsers; allow a malicious attacker to somehow force a user to download a malicious file.
Except that such a vulnerability will probably get marked "no fix" in any bug tracking system...

I agree, people should grow up; if one had the ability to operate blogs it doesn't mean you're any particularly good at security. And shouting out flaws before even checking your work is even more immature.

Christian Sciberras

Jul 14th 2010, 08:39

OK, let me put this in layman's terms for you.

What he did can be replicated in ANY BROWSER (firefox msie opera safari etc) and exists SINCE THE 1990's, when Internet Explorer supported ActiveX plugins.

So sure, Google Chrome is "flawed"; as are all the the other browser. Now if you want to keep away from the Internet indefinitely, be my guest.

Andreas Grech

Jul 14th 2010, 14:10

@M. Azzoppardi:

Yes obviously any one who knows simple JavaScript could have written this code. So, what is your point exactly? I did not write the post to show my JavaScript skills.

And also, a user has to OK the extension before being installed in their browser, yes. Google Chrome and other browsers even give you a warning before installing 3rd party extensions. Yet, the reality is that many users disregard the warning completely.

Here's an example: http://blog.mozilla.com/addons/2010/07/13/add-on-security-announcement/

That Mozilla article was written yesterday, and in it they talk about an add-on, Mozilla Sniffer, that intercepts login details and sends this data to a remote location:

"Mozilla Sniffer has been downloaded approximately 1,800 times since its submission and currently reports 334 active daily users. "

The point of my post is to make people more aware that such malicious activities can happen, and just because a warning is presented to the user before installing, doesn't mean that the user will read it.

Maybe with a demonstration, like the example in my post, people will be more careful.

Andreas Grech

Jul 13th 2010, 22:05

@Adrian:

I did not produce any sort of malware. The reason I wrote the post is to make people more aware of the dangers concerning the installation of 3rd party applications. What I demonstrated was a proof of concept that an attacker could implement to steal login credentials.

I did not upload the extension to the Google Chrome repository because my intent was not to exploit people but to show what can be done.

The extension was written by myself using the jQuery framework and nothing was stolen. jQuery is dual-licensed under the MIT license and the GNU General Public License. If you think that I have stolen something, please review the specifications of those licenses and comment again.

Andreas Grech

Jul 13th 2010, 22:07

@Julian:

As you have correctly said, the "vulnerability" is the user, not the browser. That's why we need to make people more aware about the situation and what can be maliciously done with these extensions.

PS. I never used the word "vulnerability" in my post.

Andreas Grech

Jul 13th 2010, 22:26

@Joe:

You have completely missed the point of my post. I didn't write this extension to spy on people. Why would you ever have such a misconception? Actually, come to think of it, have you even read my post?

First off, I have never said that this is a vulnerability in the Google Chrome browser. Secondly, as regards your comment about gaining access to "your DOM" (whatever that means), as I stated earlier on, you have completely missed the point of my post.

My post was to make users more aware that such malicious activities can happen when dabbling with 3rd party extensions. Since when has it become wrong to remind people about their security and protection of private data?

Joe Mifsud

Jul 14th 2010, 10:10

@Andreas
Also, I was not indicating that you wrote the plugin to spy on people. I said that you wrote spyware, which is true correct? I am not implying that you intend on using it for malicious purposes; but simply that you wrote a spyware plugin which is no different from the archives of spyware available on the net which come in many different forms including plugins. I made this statement to simply point out that no, as the times reported no 'vulnerability' was found. If you want to state that the users are the vulnerability (which is usually most often the case) that is fine, but the times should not pretend that this is breaking news :)

M.Caruana

Jul 13th 2010, 21:47

What I meant by traditional google is the old search engine. I only tried installing the new chrome google and actually ended up infected with a virus instead. As others implied once you start installing unsafe plug ins you are asking for trouble. Even with active x one must be cautious.

JosephA Borg

Jul 15th 2010, 17:17

"even with AcitveX one must be cautious"

Actually ActiveX seems to be the worst security example you could come up with… I assume you installed the chromium plugin that makes IE sort of behave like a good internet citizen.

You might want to try a Google Chrome instead of IE or Firefox or Safari or Opera… they're all better choices than Internet Explorer … really …

Andreas Grech

Jul 15th 2010, 16:26

@Ivan Zammit:

Yes, it's unfortunate that such a mistake has been made by the reporter. Thankfully, it has now been fixed.

Oh and just to make it clear to everyone: I did not develop an extension named jQuery -_-

Joe Mifsud

Jul 13th 2010, 19:51

I'm not sure if this is sarcasm or not... if it is sarcasm and you are insinuating that users should use telnet to browse the web then good joke :)

If not, I have no idea what you are on about!

Also, if you try your example with on an SSL port the following error code is returned:
SSL Error Response: Z0BB1

O Darmanin

Jul 13th 2010, 23:01

Lol ... I loved this one !!! and maybe you'd need to interpret HTML code and execute all the scripts manually as well, trapping any security issues as you go along :)

good one.

Joe Mifsud

Jul 13th 2010, 20:03

Besides sounding like an advert, you are incorrect in your assumption that lastpass helps with this 'vulnerability'.

Lastpass is simply a password manager. Your password is still entered into the browser programmatically using lastpass instead of using the keyboard. This results in the related changes in the DOM in the browser. This 'vulnerability' extracts information from the DOM. So, no last pass doesn't help. Even in other net attacks (such as man in the middle), the password is still sent over the same internet connections and using the same encodings, so it is just as vulnerable as not using last pass.

From what I can tell last pass will just cause pain for people who use it. If you rely on one password to use last pass (and last pass then outputs different passwords according to the site) - then what will you are not on your PC which has last pass installed? Or better yet when you are on a PC where you do not have access to install new software (such as last pass)? Seems like a hassle to me.

Andreas Grech

Jul 13th 2010, 22:29

@Ian:

I never said that this is a vulnerability in the Google Chrome browser. And although it's true that users are warned before installing 3rd party applications, the reality is that the majority of users do not regard these warnings, and that was the point of my post.

I am simply saying that people should be careful about what they install on their computers.

Christian Sciberras

Jul 13th 2010, 18:23

What do you mean be "Google Chrome" and "traditional google"? If you're speaking of the search engine, it doesn't have anything to do with a web browser.

As to local talent...sure as long as you get them to cooperate. But that doesn't happen; we both have web developers from the 90's and modern "web 2.0" developers - each going their own way.
It's how competition works in Malta, it simply had to turn out to be destructive.

Andreas Grech

Jul 14th 2010, 00:44

@Christian:

"as long as you get them to cooperate. But that doesn't happen;"

What exactly are you implying?

Christian Sciberras

Jul 14th 2010, 08:40

That local companies do not cooperate at all??

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