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Comcast Injecting Popups About Modem

Posted: Sun Jun 30, 2019 11:35 pm
by The Egg
I recently upgraded my Comcast service from 25mbit to 150mbit. My modem is an old SB6120 4/2 model from 2010, and only seems to be able to manage 140mbit down. Whatever. 10mbit off the top is nothing. My buddy recently gave me a Netgear 32/8 model anyhow, which I'll install when I dang well get around to it.

The problem is Comcast constantly harassing me about the situation. I get several emails each week, multiple physical letters in the mail, and now this...

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Somehow Comcast is randomly injecting this popup on me, both on iOS Safari, and now in W10 Chrome, and defeating content blockers on both of them. Can someone more knowledgable than myself tell me how they're managing to do this? Just as important, how do I slam the door on it?

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 8:27 am
by SuperSpy
They are doing javascript injection on the pages headed to your ip address. As far as I know, there really isn't a way around it. TLS-encrypted pages are immune to injection, but I don't think there's a way to stop it on normal unencrypted pages.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 8:47 am
by The Egg
SuperSpy wrote:
They are doing javascript injection on the pages headed to your ip address. As far as I know, there really isn't a way around it. TLS-encrypted pages are immune to injection, but I don't think there's a way to stop it on normal unencrypted pages.

Thanks for the info. That's exactly what they're doing. Quite unnerving, and were it not for them already heavily nagging me via other methods, I might have suspected malware. Calling and ragging on a CSR isn't likely to accomplish much, so maybe it's just time to start looking at VPNs.


"Unwanted man-in-the-middle (MITM) code insertion now happens in Xfinity connected homes, as well – a stark reminder that such an attack vector exists. Simply put, this is a centralized vulnerability that could be easily exploited by law enforcement or other nefarious actors."
Yep

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 8:57 am
by LostCat
The Egg wrote:
Thanks for the info. That's exactly what they're doing. Quite unnerving, and were it not for them already heavily nagging me via other methods, I might have suspected malware. Calling and ragging on a CSR isn't likely to accomplish much, so maybe it's just time to start looking at VPNs.

Spending money either way. A modem switch (especially if you've already got one) is likely a lot simpler solution.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 8:59 am
by roncat
You can get a comcast email account and they will spam that instead of injecting popups. :D

Or... you can redirect your efforts to installing the new modem, and get 180Mbps down and 25Mbps up all day long. You won't be fighting your neighbors for bandwidth on the same 4 channels anymore (having 32 to choose from), especially if you give them your old modem.

Not sure why I get 25Mbps up when I do the speed tests, the plan says you should only get 10 (+20%). Don't tell anyone...

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 9:09 am
by just brew it!
roncat wrote:
Not sure why I get 25Mbps up when I do the speed tests, the plan says you should only get 10 (+20%). Don't tell anyone...

Occasionally, incompetence on the part of a service provider actually works in your favor!

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 9:11 am
by The Egg
roncat wrote:
You can get a comcast email account and they will spam that instead of injecting popups. :D

Or... you can redirect your efforts to installing the new modem, and get 180Mbps down and 25Mbps up all day long. You won't be fighting your neighbors for bandwidth on the same 4 channels anymore (having 32 to choose from), especially if you give them your old modem.

No....that doesn't stop anything. They're already spamming via email, plus regular snail mail, probably phonecalls soon, and, if I don't change the modem by next week, I expect to get out of the shower and see a message written in the steam on the mirror. I don't know what the deal is with them and the g- d- modem, but the javascript injection is over-the-top and uncalled for.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 9:29 am
by just brew it!
I had heard that they pull crap like this, but have not experienced it myself (yet).

If you're willing to pay the extra for business class they will leave you alone, and you also get much more responsive customer service when things go wrong. (One of my co-workers has Comcast business class and has been reasonably happy with it.)

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 10:30 am
by Waco
roncat wrote:
Not sure why I get 25Mbps up when I do the speed tests, the plan says you should only get 10 (+20%). Don't tell anyone...

Perhaps you can get them to screw that up for me too! I'm stuck at 12 Mbps up and they literally won't sell me more bandwidth regardless of cost.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 11:35 am
by ludi
Some of the Comcast plans run faster than advertised if you don't have congestion in the area, and in the case of the 10 plan getting 25, you may have been upgraded and not noticed the announcement email. We originally subscribed at 25mbps but then Comcast made improvements in the area a few months later, and upgraded our plan to 50 and then 60mbps with no price change. At every speed tier, I typically get about 5-10mb more than nominal when I run a speed test.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 11:46 am
by puppetworx
Has anyone ever pwned one of these ISP JS injectors?

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 12:08 pm
by Waco
ludi wrote:
Some of the Comcast plans run faster than advertised if you don't have congestion in the area, and in the case of the 10 plan getting 25, you may have been upgraded and not noticed the announcement email. We originally subscribed at 25mbps but then Comcast made improvements in the area a few months later, and upgraded our plan to 50 and then 60mbps with no price change. At every speed tier, I typically get about 5-10mb more than nominal when I run a speed test.

Sure, but that generally doesn't hold true for upload speeds. I've got 250/10 and routinely get about 20% over that...but no amount of money will make them bump my upload bandwidth. :/

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 12:31 pm
by ludi
Well, no, you have to purchase Business Class if you want fast uploads.

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 12:57 pm
by Waco
ludi wrote:
Well, no, you have to purchase Business Class if you want fast uploads.

I've attempted that, they appear to be reluctant to sell me a "business" line for personal use. I didn't think that broke any rules, but apparently the rep I got in touch with thought differently.

I'll try again in a few months. :P

Re: Comcast Injecting Popups About Modem

Posted: Mon Jul 01, 2019 1:38 pm
by qmacpoint
Quick question - could it be that they're redirecting some DNS records to their ad service? have you tried using 1.1.1.1, or any of the Google DNS servers? worth a shot...