How can I trust Firefox?

How can I trust Firefox?

Rate This

[Fixed issues with images; sorry]

[Removed the clear=all problem; thanks for pointing it out]

[Added a follow-up post here]

Recently, a lot of volunteers donated money to the Firefox project to pay for a two-page advert in the New York Times.

If only they had spent some of that money on improving the security of their users by, say, purchasing a VeriSign code signing certificate.

Let me explain...

One of the many criticisms of Internet Explorer is that customers are fooled into downloading spyware or adware on to their computers. This is indeed a legitimate problem, and one of the ways you can reduce the risks of getting unwanted software on your machine is to only accept digitally signed software from vendors that you trust. Every time you download a random piece of software from a random location, you're taking your chances with your PC and all the information stored on it. You wouldn't take candy from strangers, would you?

In order to help protect customers, the default install of Internet Explorer will completely block the installation of ActiveX controls that are not signed, and it will suggest that you do not install any unsigned programs that you might try to download. Of course, just because a piece of software is signed (or you have the MD5 hashes for it) doesn't mean it isn't nasty; it just provides some evidence you can use to make a trust decision about the software (in logical terms, it is a necessary but not sufficient condition for trusting software).

So what happens when a typical user decides it's time to download Firefox and enjoy the secure browsing experience that it has to offer? Well, sit back, relax, and let me take you on a journey.

First of all, I went to the advertised, and was redirected to the real page at
From there I easily located the download link, and clicking on the it gave me the following dialog:

Download Firefox image

Hmmmm, wait a minute. I went to, not I don't have any idea where that place is, and it sure makes me nervous. IE has informed me that "If you do not trust the source, do not run or save this software."

Do I really trust a bunch of kids at some random university I've never heard of? Hopefully, the average person will decide that they do not trust this web site, and they will click Cancel. No Firefox for you!

But being a brave soul (and not caring if my Virtual PC image dies a horrible death) I click Run. A few seconds later, I get the following dialog:

Picture of unsigned Firefox executable warning


Not only does this software come from a completely random university server, but I have no way of checking if it is the authentic Firefox install or some maliciously altered copy. (I sure hope those 10 million people who have downloaded Firefox so far haven't all download backdoors into their system...). Since "You should only run software from publishers you trust" and since the publisher cannot be verified, I should click Don't Run (which is, thankfully, the default).

But, again, being a brave soul I click Run.

I am then greeted with this dialog:

'Picture of random setup dialog --

Oops, my network connection died. But still... that kind of unintelligible dialog doesn't do anything to make me trust the installer. Maybe this is a trojaned copy of Firefox after all?

Forging blindly ahead, I download the software again (this time coming from -- I kid you not! -- a numeric IP address, the bastion of spammers and phishers and all manner of other digital rogues) and run the installer. This time things are actually looking good:

·Installer runs fine

·I accept the defaults

·Firefox starts

·It asks if I want to make it the default browser; no thanks

·I get this dialog (seriously):

Picture of blank Message Box (not even a title bar)

Hmmm, a completely blank MessageBox. Well, OK is the default choice, so I guess I should accept that. No idea what it will do to my system though.

My confidence in this software is growing in leaps and bounds.

I decide to reboot the VPC just in case that dialog was trying to tell me something important. After rebooting, I boot up Firefox and it seems to be working fine.

I decide to install some extensions because, hey, everyone on Slashdot loves them so much. I browse to the extensions page and decide that the Sidebar sounds cool (I love Amazon, and Amazon loves my credit card). Clicking on the link brings up this dialog:

Picture of Firefox Extension Install dialog

It dutifully tells me the extension isn't signed (good), but makes the default choice Install Now (bad). This is the opposite of what Internet Explorer decided to default to when it detected unsigned code (ref: above). Now tell me again, which is the more secure browser?

(Just so I don't get inundated with comments about this, Firefox does disable the Install button for a couple of seconds when the dialog is first displayed, but by the time I had finished reading the text in the dialog it was enabled and ready to go).

Next, I want to go somewhere that uses Flash (heh, coz we all know I love Flash!). I'll try the Ocean's 12 official web site,, which detects that Flash isn't installed and gives me a link to install it. Clicking on the link, I get taken to the Macromedia page, where I can download Flash. Firefox prevents me from running the executable straight away, and forces me to save it to disk. That's probably a good move for most users, although personally I tend to click Run inside IE because I know it will warn me about unsigned programs. Nevertheless, it is but a minor speed bump on the way to malware infection, as we shall see in the next step.

Once the file is saved, I can open it from the little downloads dialog that pops up. The problem is, there is no indication as to whether or not the file is digitally signed; I just get the usual "This could be a virus; do you want to run it anyway?" dialog. But without any evidence to base my trust decision on (where it came from, who the publisher was, etc.), what should I do? Of course, the right thing to do would be to delete the file and never install Flash, but I really want to install it so I guess I have to go ahead and run the thing.

What's really frightening though is that there is a "Don't ask me again" option in this dialog... which means that if you check the box you could end up running any old garbage on your system without so much as a single warning. Doesn't sound so secure to me...

So anyway, Flash installs and I can view the Ocean's 12 website OK. But now what if there's a security bug found in Flash and I want to disable it? With Internet Explorer, I can simply set the Internet Zone to "High" security mode (to block all ActiveX controls), or I could go to the Tools -> Manage Add-Ons dialog if I just wanted to disable Flash until an update was available. How do I disable Flash inside Firefox? Good question. I don't see any menu items or Tools -> Options settings, the Tools -> Extensions dialog doesn't help, and Flash isn't even listed in Add / Remove Programs.

According to Google, I have to download yet another unsigned extension to enable the blocking of Flash content. Ho-hum. The first download mirror that the page sent me to gave a 403: Forbidden error; luckily the second mirror worked OK and, once again playing digital Russian Roulette, I installed the extension and rebooted Firefox twice (yes twice) as instructed to install it. To be fair, the extension is pretty cool, but that's not the point: How do I know I didn't just install some terrible malware from a compromised web server? Who owns anyway, and can their admins be trusted? And what if I accidentally browsed to some site hosting a malicious Flash movie whilst trying to download the extension?

(Always remember the Ten Immutable Laws of Security, and in particular Law #1: If a bad guy can persuade you to run his program on your computer, it's not your computer any more.)

To continue my benevolent fairness, I actually think Firefox is a nice browser. It seems to render HTML without any problems, and the tabs are nice for browsing Slashdot. But just because it doesn't currently have any unpatched security vulnerabilities talked about in the press doesn't mean they don't exist (Secunia currently lists three unpatched vulnerabilities, for example).

Mozilla has had its share of security vulnerabilities in the past (just as IE has), and -- despite what the open source folk might say -- Mozilla keeps their security bugs hidden from the public (just like Microsoft does) in order to protect their customers from coming under attack by malicious users. Note that this is not a bad thing; all vendors should treat security bugs responsibly to ensure customers are not put at undue risk. It's just something you should be aware of. Just because you don't see any unpatched security bugs in Bugzilla doesn't mean they don't exist, either.

But the thing that makes me really not trust the browser is that it doesn't matter how secure the original code is if the typical usage pattern of the browser requires users to perform insecure actions.

·Installing Firefox requires downloading an unsigned binary from a random web server

·Installing unsigned extensions is the default action in the Extensions dialog

·There is no way to check the signature on downloaded program files

·There is no obvious way to turn off plug-ins once they are installed

·There is an easy way to bypass the "This might be a virus" dialog

This is what the "Secure Deployment" part of Microsoft's SD3+C campaign is all about; we design and develop secure software, but we make sure that customers can deploy it securely as well.

I personally don't care if people choose to run Firefox or Linux or any other software on their computers -- it's their computer, after all -- but we'll never get past the spyware / adware problem if people continue to think that installing unsigned code from random web sites is A Good Idea.

So, at this point in time, installing (and using) Firefox encourages exactly the sort of behaviour we are trying to steer people away from, and to me that makes it part of the problem, not the solution.

(Thanks to Mike and Robert and the other folk who gave this a once-over before posting; any errors are still mine though ;-) ).

  • I spend most of my time in the Computer Industry removing spyware/adware from home users and business users who don't understand anything about security. That is the way the industry is. THE ABSOLUTE most effective solution i have found to date, is to disable internet explorer, install Firefox, install Spyware Blaster, Install Spybot Search and Destroy (tea timer).

    Since performing these actions on hundreds of clients computers i have not had ONE (Not even a little one) of those clients ever have a problem with spyware/adware.

    Btw, didn't your mother teach you to always save to disk instead of running files from the online location! tut tut!
  • GDawg: This page doesnt even render correctly in Firefox. Half the article is scrolled way down - you wouldnt even know it is there!! what the.....
  • The war of operating systems' security is restarted; the war of browsers' security is restarted; the war of security seen as lines of codes is also restarted; There is the situation in the last days; there are some of my toughts on the subject; take this post as a trackback:
  • Well I certainly don't miss the automagically changed home page, unrequested added toolbars, flurry of popups, and self installed spyware that I was plagued with when I used IE. Microsoft has had 9 years to prove whether they know how to handle network security correctly (I figure MS didn't really have a networked machine until August 1995) and have thus far failed. I'm quite willing to give Mozilla the next 9 years to prove themselves one way or another.

    Yeah - I know - "Wait until the next version. It'll be awesome. Honest." (c) 1972-2005 Microsoft, Inc.
  • Flame on!
  • How do I trust Verisign? I mean I seem to recall quite a few stolen keys being released in the past. You want security. Use a VM like you did. Don't allow the user to install anything. Without doing a su or RunAs. Oh wait I forgot.....Windows XP wants you to be Administrator by default.
  • Congratulations, you just started a flamewar. >:(
  • this guy obviously does not understand that if one approaches something from a very narrow convoluted worldview people are instantly going to recognize that he's unsuitable to take advice from.

    let's get this straight - he doesn't trust a bunch of kids at a school putting out software.
    However he'll trust a bunch of execs at a major corporation.


    your narrowmindedness is exceeded only by your narrowmindedness
  • "Firefox is an unknown quantity and without any form of formal prerelease testing, I don't trust it"

    no prerelease testing? How long was it available in beta form? at least two years.
    At least I know that if Firefox crashes, it won't take Windows with it.
  • As a lover of open source and a lover of Firefox, I'd like to say thanks for your helpful suggestions. I hope Firefox will take them on board.

    I apologize for all the reactionaries who may mistakenly flame you.

    Will Smith
  • Bias anyone? Sorry, but Firefox is not meant for complete idiots. IE has had this great security policy for how long? About a month? Only after years of screwing people and their computers over and strong-arming its way into the marketplace.
  • How do I trust Verisgn?
  • if it's a choice between possibly downloading a copy of FireFox one time which may be trojaned, which i can check by comparing MD5Sum's after i download, or using IE and being infected with a new piece of spyware every 5 days, i choose to take the 1-time risk of Firefox.

    and by the way, on the whole, mirrors have a very good security track record. only very few times has an application been found to be trojaned on a mirror, and checking the MD5 or PGP signature usually prevents the trojaned software from even getting installed.
  • "Of course, just because a piece of software is signed (or you have the MD5 hashes for it) doesn't mean it isn't nasty; it just provides some evidence you can use to make a trust decision about the software (in logical terms, it is a necessary but not sufficient condition for trusting software)."

    You failed logic class, didn't you? No, that is not a translation in logical terms, unless you honestly believe every piece of software without a signature will do bad things to your computer, or at the very least you honestly believe that there is no way one can trust a piece of software without a signature. Necessary does not "provides some evidence" about something, in logical terms it is a conditional.
  • Do you realise that ALL ur errors did come from all the third parties software u have installed ? Next time to be real, try on a blank install, with no buggy AV or other thing intereacting.

    On code signing, Mozilla project is open source and commited in its politics too and the last thing the project will do is to invest into stupid code signing whereas the good old unix md5, sha-1 ang gpg signing are as reliable if not more ( you have 3 unique ways to check your binary ).

    Take it or leave it.
Page 3 of 94 (1,408 items) 12345»