GMail security hole


in Daily updates, Geek stuff, Internet matters, Security

Path to Marston

As people who read techie news pages like Engadget and Slashdot already know, a somewhat serious security flaw in GMail has recently been uncovered. Specifically, when you are logged into GMail in one browser window or tab, any other site you visit can grab your entire contact list. Whether that is a serious leak or not is a matter of perspective. Certainly, it exposes all of your friends of even more spam than they already receive.

Read the following carefully before you click anything. If you want to see the script that grabs contact lists at work, follow this link. Engadget says it’s “non-malicious,” but the risk is yours. The bug arises from the way in which GMail stores your contacts as a JavaScript file that can be requested by other websites. Google claims they have fixed the bug but, as the link above will prove, they have not.

Plausible attacks

A site that wanted to be really sneaky could exploit this information in many ways. At the very least, it could be used to very easily identify many of the people who are visiting. Knowing someone’s contact list might help in the launching of phishing attacks. It could, for example, make it easier to work out what company someone works for. You could then find out who does their information technology and send spoofed emails that seem to come from the IT department, asking for passwords or other sensitive information.

If it is a site that contains content that many people would not want others to know that they view, it could grab the email addresses for people with the same last name as you and threaten to send them information on your surfing history. A less complicated ploy would be to use emails that seem to come from people who you know to get through spam filters. Because of email spoofing, it is very easy to make messages seem to be coming from someone else.


As someone with 1037 MB of data in my main GMail account – including 14,410 emails and more than 1500 instant message conversations – I am naturally very concerned about GMail security. There is tons of stuff in there that I would be profoundly opposed to seeing on a public search engine, as has already happened in at least one case with private GMail data.

Contrary to their own assertions, Google had analysed and indexed all e-mails processed through their mail service. Due to a mistake made by an administrator, a database of the highly secret project was mirrored onto the external index servers, and as a result, the private mails of thousands of GMail users could be accessed via the search front-end for at least one hour.


Clearly, it would be preferable if GMail started using durable encryption on their archived messages. This would both protect the messages from hostile outsiders and keep Google from doing anything undesirable with them. Even a passphrase based symmetric-key encryption system (perhaps based on AES) would be an improvement. I bet all the students at Arizona State University, which had turned to GMail to provide all their email services would feel likewise, if they knew.

[Update: 8:30pm] This article by Brad Templeton, the Chairman of the Electronic Frontier Foundation, makes some good general points about GMail and privacy.

[Update: 11:00pm] According to Engadget, this hole has been fixed. It’s good that it was dealt with so quickly, but there are still reasons to be concerned about GMail security in general.

[Update: 2 January 2007] The mainstream media has caught up with the story. CBC News: Teen exposes Google security flaw.

[Update: 18 July 2008] GMail just added a very useful ‘Activity on this account’ feature. It tells you (a) whether any other computers are logged into account and (b) when and where the last five logins took place from. This is excellent.

{ 4 comments… read them below or add one }

Milan January 1, 2007 at 7:49 pm

On a largely unrelated note, you should see how many movies / albums / games you can download just by doing a Google search for the following, with the name of what you are looking for added to the end:

intitle:”index of” “last modified”

It will lead you to masses of FTP servers that are just sitting there, often full of copyrighted material.

Milan January 1, 2007 at 10:15 pm

That would require the hole to stay open for quite a long time. It already seems as though the link above does not work on my setup: Firefox 2 in Mac OS 10.4.

R.K. January 1, 2007 at 10:00 pm

I smell a business model:

1) Establish and (the premier site for people who have and act upon shameful, illegal sexual urges)

2) Collect contact list information via GMail bug, from visitors

3) Assemble dossiers of what they look at

4) Threaten to email said dossiers to friends, family members, and co-workers

5) Profit obscenely

Milan January 6, 2007 at 4:29 pm

A discussion relating to GMail security and login tracking is ongoing:


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