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TeamViewer stopped working? Let me guess, your ISP is TalkTalk…

If you have ever had to provide remote technical support to a less-nerdy friend or member of your family, you’ll know just how hard it can be.

Over the phone you’re trying to get them to say what they can see on their PC screen, and attempting to describe the button they should be clicking on, or the file they need to drag from one folder to another.

Frankly, it’s a nightmare.

A much easier way to do remote technical support is to use a program that allows you – with permission, of course – to take remote control of the distant PC, and fix it over the internet. You literally take over control of the mouse and keyboard, and can see what is on your “patient”‘s computer screen.

Trust me, it’s a much easier way to fix things – and avoids the need to take a lengthy road-trip to their house.

Many in the IT world use software like Team Viewer to do this remote technical support, and help their friends and family out when they find themselves in a PC pickle.

But here’s the problem – bad guys use Team Viewer too. For years scammers have been contacting vulnerable people, pretending to be from their ISP or Microsoft technical support, and offering to clean-up non-existant virus infections. Because there’s no need to.

If you make the mistake of granting one of these criminals remote access to your computer to “clean it up” you may find that they end up stealing your files, planting malicious code, and even demanding you pay a fee for their bogus service.

British ISP TalkTalk has decided that the problem of scammers defrauding its customers has become so big that they have blocked usage of TeamViewer from its network.

That’s bad news if you’re a scammer, but it’s even worse news if you happen to be a TalkTalk customer who routinely uses TeamViewer to help out friends and family diagnose and fix computer problems.

Unfortunately it took TalkTalk a while to admit that they had blocked the software, leaving many customers posting messages on its forum in the dark as they spent hours trying to get to the bottom of why the software they relied upon was no longer working.

Eventually TalkTalk ‘fessed up that it was responsible for the block:

Apologies for the confusion, but I can confirm that we have implemented a number of network changes that have blocked a number of applications including Teamviewer

We constantly monitor for potentially malicious internet traffic, so that we can protect our customers from phishing and scamming activities. As part of this work, we have recently blocked a number of sites and applications from our network, and we’re working hard to minimise the impact on our customers.

We are working with teamviewer and other 3rd parties on implementing some additional security measures that would enhance the security to all customers of these services but we will continue to block any sites/applications reported by customers to reduce the opportunity for fraud to take place.

I can’t help but give a wry smile at the thought that TalkTalk is the one claiming to give security advice to others. This is, after all, the firm which suffered a massively embarrassing data breach after it was hit by an elementary SQL injection attack.

Judging by the forum messages, TalkTalk’s customers are unimpressed by the decision:

I and no doubt a great many other customers have been using Teamviewer (via TalkTalk) for many years without any problems, now all of a sudden with no prior warning we can’t and no one is saying how long (if at all) before we can use it again. Corporations, Businesses and IT departments worldwide can use Teamviewer but Talktalk customers can’t. Extremely unsatisfactory customer service IMHO.

It feels to me that TalkTalk had good motives, but has handled this issue poorly. It’s no wonder TalkTalk’s customers are upset.

About the author


Graham Cluley is an award-winning security blogger, researcher and public speaker. He has been working in the computer security industry since the early 1990s, having been employed by companies such as Sophos, McAfee and Dr Solomon's. He has given talks about computer security for some of the world's largest companies, worked with law enforcement agencies on investigations into hacking groups, and regularly appears on TV and radio explaining computer security threats.

Graham Cluley was inducted into the InfoSecurity Europe Hall of Fame in 2011, and was given an honorary mention in the "10 Greatest Britons in IT History" for his contribution as a leading authority in internet security.


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  • It just shows you that,with the internet, how easily our communication can be controlled / blocked instantly and we can do nothing about it. It could therefore also be blocked by anyone hacking/controlling the ISP configurations: they only need to infiltrate the ISPs and they have us all. I am sure a national secret service organisation would have no problem, whether officially or otherwise, blocking our connectivity and because of our reliance on the internet, paralysing us in any desired respect.

  • What an utter stupidity Talk Talk is once again showing. Thank God they are not in charge of the military, since otherwise they would propose to "simply detonate a bunch of nukes, since after all… that will kill the bad guys too."

    What a stupidity.

  • I used to like VNC but AV products started to report it as a PUP, and we eventually had to use something we developed in-house instead. I wonder how many TalkTalk customers will now use different remote control software because of this. Teamviewer should sue!

  • Talk Talk behaved the same way some years ago when they launched their Broadband Free Forever campaign and without making it known started started throttling ports that Valve software Steam platform used. At the time their technical support was on a premium call rate and if I remember correctly it was around 50p per minute.

  • Today I rang a retired lady whose PC I look after and whose ISP is TalkTalk to warn her that I wouldn't be able to take over her PC to sort out problems in future because of this action by TT.

    She said, "But it's still here on my screen!" so I explained that although the TeamViewer app was there, it wouldn't be able to talk to my PC. And I proceeded to demonstrate. She started her app, I started mine, she told me her ID number and PIN which I entered and…. connected!

    Somewhat dumbfounded, I was able to retrieve a lost Word toolbar for her.

    Wondering if TT are still rolling out the block and not yet got to her connection or have they changed their minds and removed the block in view of the outcry?

  • We used TeamViewer in our environment for a while but had to have it removed due to vulnerability issues. I would like to see if I can get this tested in our environment where some users were using TeamViewer.