Tool Detects "In-Flight" Webpage Alterations

TheWoozle writes "In a follow-up to a recent story about ISPs inserting ads into web pages, the University of Washington security and privacy research group has teamed with the International Computer Science Institute (ICSI) to develop an online tool to help you identify if your ISP is inserting ads or otherwise modifying the web pages you request."

Should just block all ads, but...

If that isn't desirable, do a patch to Apache that creates a header that holds a hash of the content.
The hash gets calculated once for static content, which is usually the bulk of the traffic, no? So
not too big of a hit.

Browser sees content. Browser sees hash. Browser compares the two...

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Frames

What if the ISP is simply putting the web-page in its own frame, and the advertisement in a second frame? Unless you add the ability for web-pages to dictate that they should not be in frames, this one can't really be trapped for like that. The ISP could c

Re:Should just block all ads, but...

All these ideas are neat, but ultimately losers.
MOVE TO ANOTHER PROVIDER TODAY.

Why should I do that if I don't know the ISP is modifying the web pages in flight? Maybe I need a tool that could somehow detect that? That would sure be useful. Oh wait...Isn't that what this discussion is about?

Re:Should just block all ads, but...

What if the ISP, having the server's (Apache HTTPD) code, recomputes the hash in the same manner. Browser sees content. Browser sees hash. Browser compares the two...gets an OK.

1.) Claim the hash is to protect the copyright on your site
2.) Sue any ISP that alters the site without permission under the DMCA
3.) ???
4.) Profit!

Oh lord the confusion

Do we sue the ad folks for inserting ads and stealing content? I mean, in just about any other medium this would wind up in court overnight as copyright and stolen content and so on. But now we have a circumvention tool to detect it...so are we going to get sued under DMCA like nonsense for attempting to circumvent the ad insertion?

Re:Oh lord the confusion

Not exactly. A book is just a book. Words on paper. A webpage is FAR more visual than text on page (unless you have been sleeping the last few dozen years). Inserting ads could easily be considered a derivitive work since you are altering the look of the site. What if I didn't want ads? What if my design is a nice soft brown and then you start inserting pink flashing ads? Or God forbid, these clowns insert one of those drive by installer ads, now your business reputation is completely screwed because some major ISP decided to make a buck without checking their sources and your website infected thousands of consumers. Good luck explaining to your customers how it was the ISP magically sneaking ads onto your website.

Next week on Slashdot

ISPs intercepting, altering results from online security tool

Re:Next week on Slashdot

We are specifically worried about this case. But we have some thoughts on how to make it more difficult for someone to do that, which will probably end up in a full paper later.

Answers to questions in this thread

We (the authors of the page) will be answering questions in this thread.

Analyses

We've seen a couple cases of NebuAdd, one other that looks interesting, and a fair amount of addblocking/firewall software (eg, ZoneAlarm does some modifications)

We are waiting for the Slashdot and DIGG deluges to pass, however, before we have a more detai

Re:

HTTPS, when certificates are properly used, is designed to prevent man in the middle viewing and modification.

Re:Answers to questions in this thread

Strauss Creamery Soft Serve vanilla with sea salt and olive oil from Pizzeria Picco [pizzeriapicco.com] in Larkspur

Re:

One of the big reasons is the certificate model...

If you self-sign, everyone gets a nag panel everytime they visit your web page. If you have verisign or someone else provide you with a certificate, it costs real money.

Also, the HTTPS handshake is expensi

Not quite...

This is a war however which we can make damn difficult by using virus-like mutation techniques, so that every checker looks different: force THEM to solve the AV defender arms race.

As long as the actual API used by the Javascript is common enough that the ad-injectors can't recognize and block our code by keeing in on the API calls rather than the overall Javascript.

The proper solution, adding integrity checking to all HTTP, seems like its not happening.

Please don't post negative results!

No need for thousands of "All good in Kalamazoo" & "Up to date in Kansas City" posts.

A possible workaround

A friend of mine had a similar problem with his webpages. They were on a free host (rolls eyes). I wrote a script for him to store special tags to denote the beginning and the end of his webpage content. After the webpage was loaded, a script erased everything and replaced all the html with his marked content. Ta-da, no ads!

If you want to be stricter, encode your webpage content with base64 to make sure the ads don't intrude your precious content.

Re:A possible workaround

I'll bet that his user agreement with that free host also clearly states that circumventing their added content in the manner that your script does is prohibited. If they discover your script, they'll likely disable his account.

Re:A possible workaround

For sites like GeoCities that add

</object></layer></div></span></style></noscript>< /table></script></applet>(...adverts...)

to the bottom of your page to stop you trying to hide their adverts, it could be good to add <plaintext style="display: none"> to your page just before the point where they add their junk. plaintext is the unstoppable monster [htmlcodetutorial.com] of HTML – there is no closing tag, and the rest of the page will be treated as plain text instead of HTML. It's a slightly obscure feature, but it has better support between web browsers than many other parts of HTML and it can be fun to play with...

Inserting Ads

A certain ISP in Canada [userfriendly.org] delt with this not long ago...

What about upstream modification

It seems that everyone is concerned about downstream modification, and is completely ignoring the possibility of upstream modification. What if Sprint [verizon.com] started modifying upstream http [amazon.com]-posts to start a more viral ad distribution system? Not only would they be able to target their customers [barnesandnoble.com], they would also be able to target the customers of anyone who could read the post!

This is the reason that we need to push for network neutrality [handsoff.org]. When the only choices are between a giant douche [summerseve.com] which alters content and a turd sandwich [panerabread.com] which alters content, the customer ends up screwed [lowes.com] in the end.

They WANT to be slashdotted

These guys actually want as much traffic as they can get to get a good idea of what isps are doing what. Go ahead, click online tool. [washington.edu] It's pretty nifty.

Old stuff.

Years ago on one April Fool's day, I got a list of ad sites (from the usual /etc/hosts files out there), then got the internal DNS server to resolve them to a server that served up the company logo instead (for all possible url paths).

FWIW, seemed only one person noticed that the forbes page they loaded somehow had the company logos everywhere :). Nope I didn't get fired or even reprimanded - plus even better - I was saving company bandwidth (remember this was years ago)... Nobody complained about the lack of ads from ad.doubleclick.net and gang.

I toyed with the idea of substituting ads with reminders (meeting at 2pm, or "you have been on slashdot for 2 hours!") and other more useful information.

Lastly, I don't think their naive hashing thing checks if you are altering the images - the content may remain unchanged, but linked to contents may change (they aren't checked from what I see), so it doesn't work for my scenario where different ads are substituted for the unaltered URL.

That said, I'm still curious on:
1) How many ISPs would bother modifying traffic from those 7 destinations they are testing.
2) What the various laws around the world say about this.
3) What those laws say about "sponsored internet access" where an ISP gives a cheaper package/plan where the ads are substituted with the ISPs advertisers with the risk of some corrupted info.
4) What those laws say about "streamlined internet access" where an ISP provides a package/plan where ads and other crap are removed (or modified) for their customer.

Re:

they're not talking about the ISP hosting the web page, they're talkign about your ISP adding ads to random sites that you visit. client-side, not server-side.

Re:I've got a better method...

Are you pretending to be mentally challenged in order to troll, or do you really not understand even after having it explained to you a little further up the page? It is not the developer's ISP, or the hosting ISP that is doing this! It is the ISP of the people looking at the page. So, you left out a step in your patented eyeball method: signing up for every ISP in existence and loading your page, to see if that particular ISP does it.

Re:

It's not the host ISP that's inserting the ads, It's the "Client" ISP, for example Joe Smith buys a computer and buys high speed internet from "ECI" the Evil Cable ISP. Joe Smith visits Bob's Website, Bob, who hates ads never put any on his webpage, and