Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Gmail blows up e-mail marketing by caching all images on Google servers

arstechnica.com

Post reply on HN
Print view View original

111–120 of 322 posts

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#111

Post by cstrat »

MrClean wrote: post #55
codeflo wrote: post #12

> E-mail marketers will no longer be able to get any information from images—they will see a single request from Google, which will then be used to send the image out to all Gmail users. Unless you click on a link, marketers will have no idea the e-mail has been seen. Absurdly wrong, marketers already use a unique image URL for each email recipient, and Google has no way to know that all of those point to the same im…

Consider this @codeflo: 1. Google may cache all images in all emails sent to gmail.com instantly and regardless of the existence of the address. This would remove the possibility for marketers to check user timestamp, remove user data from request and hide user email existence. 2. Google does _not_ need to save each image from each unique URL separately, all they need to do is fetch each image and check against an al…

I thought that 99% of the images included in emails for tracking purposes are single pixel transparent GIFs - so no biggie in working out which ones those are...

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#112

Post by vilhelm_s »

ceejayoz wrote: post #18
codeflo wrote: post #12

> E-mail marketers will no longer be able to get any information from images—they will see a single request from Google, which will then be used to send the image out to all Gmail users. Unless you click on a link, marketers will have no idea the e-mail has been seen. Absurdly wrong, marketers already use a unique image URL for each email recipient, and Google has no way to know that all of those point to the same im…

In fairness, it's a partial privacy improvement - it masks IP and user agent, as well as repeat opens.

It doesn't even mask repeat opens: as buro9 found in the sister comment, the image does not get cached, Google's proxy will request it again each time it is viewed.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#113

Post by leephillips »

ben0x539 wrote: post #56
slg wrote: post #34

Earlier quoted context omitted.

Yeah, I am not sure where the original claim is coming from. It isn't that hard for Google to simply follow the links and compare the files as part of the caching process. So unless marketers start customizing the images in addition to the links, there isn't any reason why Google can't cache the images together. And even if marketers do start customizing images, hasn't Google gotten pretty good at comparing very simi…

I don't understand how that helps. If I send an email to user_x@gmail.com with an embedded image at http://example.com/my_spam_images/image_for_user_x.jpg and google makes a request to that, I know the mail has been delivered and the user in question exists and is seeing my ads, because a request for image_for_user_x.jpg showed up in my logs. Now, when user_y also receives my spam and I get a request for image_for_us…

"I know the mail has been delivered and the user in question exists and is seeing my ads"

No, you just know that the email was delivered to the user's inbox. You don't know if the user looked at it or just trashed it.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#114

Post by jellicle »

slg wrote: post #34
trevyn wrote: post #28

Earlier quoted context omitted.

> Google has no way to know that all of those point to the same image. Try again. :)

Yeah, I am not sure where the original claim is coming from. It isn't that hard for Google to simply follow the links and compare the files as part of the caching process. So unless marketers start customizing the images in addition to the links, there isn't any reason why Google can't cache the images together. And even if marketers do start customizing images, hasn't Google gotten pretty good at comparing very simi…

The two of you are confused. The image link doesn't even have to return an image in order to successfully send information to marketers.

An image link in the email to:

http://thisalways404s.com/404/slg_read_my_email

will work just fine. So, Google will follow the link and compare the files and... wait a second, the information we care about - that slg read my email - has already been transmitted.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#115

Post by cdash »

jfoster wrote: post #109
codeflo wrote: post #12

> E-mail marketers will no longer be able to get any information from images—they will see a single request from Google, which will then be used to send the image out to all Gmail users. Unless you click on a link, marketers will have no idea the e-mail has been seen. Absurdly wrong, marketers already use a unique image URL for each email recipient, and Google has no way to know that all of those point to the same im…

I think any email marketers who want to get around this easily can. Just change robots.txt to not give permission to Google fetching the images. Copyright will laws will prevent them from wilfully ignoring that, presumably.

So they strip the images and show you a text only email and tell you to deal with it.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#116

Post by 300bps »

EGreg wrote: post #90
300bps wrote: post #78

Earlier quoted context omitted.

As someone who co-invented email image bugs with a million other programmers over 15 years ago, you are absolutely correct. (for the curious, my reason for coming up with it was to tell when a customer who requested a car insurance quote from the company I worked at read their email which instantly initiated an outbound call to them). The entire article is just plain wrong. For instance: This move will allow Google t…

There is ONE way: fetch every single image right away regardless of whether the email is even valid. And then don't store the cached version if there is no valid email. Otherwise store it and display to the user. Since every result will be a positive - false or not - no information is revealed to the marketer AND the images are displayed.

There is ONE way: fetch every single image right away regardless of whether the email is even valid. And then don't store the cached version if there is no valid email. Otherwise store it and display to the user.

Sure, in theory that works. In practice, you make an easy may to do a Denial of Service attack against Google or innocent third parties so it in actuality would never work.

Send a million emails to Gmail accounts that each have fifty links to 1 MB JPG files hosted all over the Internet. The size of the file you send to Google in the email is what - 1k? The size you are making Google download is 50 MB. This is a 50,000:1 attack ratio. You could take Google down with a 56k modem.

You could also launch a denial of service attack against any other target, courtesy of Google. Send a million emails to Gmail users that downloads JPGs on a target web server. You can even make up the JPG names to be non-existent. Again, figure your email is costing you 1k in transmission and Google is putting tremendous strain on the target server downloading 404 error messages.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#117

Post by superuser2 »

jlgaddis wrote: post #80
logicallee wrote: post #71

Earlier quoted context omitted.

There is a simple way around that. You are saying that the fact that Google retrieves images means that the mail was delivered. But this is only true if Google retrieves images only from delivered mail. If Google retrieves every image in every mail sent to @gmail.com, @googlemail.com etc, then the only thing the retrieve tells you is that you spelled "gmail.com" correctly - nothing about whether there is a mailbox th…

> If Google retrieves every image in every mail sent to @gmail.com, @googlemail.com etc, ... But they don't. If they retrieve the image, the account exists (they reject mail after the RCPT TO: stage for non-existant accounts).

And?

Anyone can check for the existence of gmail accounts in this manner without screwing around with images.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#118

Post by na85 »

drzaiusapelord wrote: post #16

So instead of my work mailing lists having accurate stats via ye olde tracking pixel, now only google does, which they will sell to their own chosen marketers and clients paying google's rate. This isn't the privacy and common-sense win you think it is.

Not sure why your "work mailing list" needs open tracking. Unless by "work mailing list" you mean "spam".

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#119

Post by martin-adams »

cstrat wrote: post #111
MrClean wrote: post #55

Earlier quoted context omitted.

Consider this @codeflo: 1. Google may cache all images in all emails sent to gmail.com instantly and regardless of the existence of the address. This would remove the possibility for marketers to check user timestamp, remove user data from request and hide user email existence. 2. Google does _not_ need to save each image from each unique URL separately, all they need to do is fetch each image and check against an al…

I thought that 99% of the images included in emails for tracking purposes are single pixel transparent GIFs - so no biggie in working out which ones those are...

Then they switch to two-pixel transparent GIFs as a workaround.

Re: Gmail blows up e-mail marketing by caching all images on Google servers

#120

Post by JohnTHaller »

kevrone wrote: post #2

Holy crap. If I'm reading this right, this basically destroys all pixel tracking, so no more email open stats, no nothing.

Email open stats have been bogus since most email clients switched to not loading external images by default.
Post reply on HN