Theoretically I should get 8 MB/s, but over the last 2 months I have hardly been getting 2.5. My ISP claims, on the phone, that my router has a virus in it from a downloaded file. They seemingly have a new technology that can infallibly detect malware in routers from their main office, but I am not sure about that. Maybe they are just lying to me.

The PCs and the other devices connected to it do not show any abnormal behaviour or malfunctions other than the slow signal. No change in DNS, no pop-ups, no redirections, no perceptible anomaly whatsoever.

I have not found anywhere on the Internet any information about malware or virus in a router that does not seriously affect the PC's performance. Even VPN filter was easily felt as it were.

Maybe I am being too suspicious just because Movistar Chile, my ISP, has a bad reputation. Maybe my router is actually infected by a virus. But what kind of virus?

Is there any known virus for routers that specializes in say, stealing information of any kind that is so furtive and discreet so as not cause any evident change in the PC, other than a slow internet speed?

Is there any known virus affecting routers for whatever purpose that has an unwanted collateral effect just slow down the internet with no other consequence in the PC's performance?

I had Bitdefender free installed when the speed slow-down started and I added Bitdefender Home Scanner Free lately which does not detect anything abnormal. Now, I am not sure whether the latter, a small program, is really capable to detect viruses in a router. Either with Wi-Fi or ethernet connection the problem remains the same. Restarting the router is no use. Does anyone knows for sure if ISPs in USA have a technology capable to detect a virus in a router -for ADSL connection- through the telephone cable from their main offices? That is my biggest doubt! If American ISPs do not have that breakthrough, why can we expect a second-rate company like my ISP in Chile, have it? How do they do it? After 3 to 5 minutes at the most of an alleged scanning process. It would not be the first time that an internet provider reduces the speed of a client to make room for new clients in the same area. Or as a way to apply pressure to force you into a more expensive plan.

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    "Theoretically I should get 8 MB/s, but over the last 2 months I have hardly been getting 2.5" on one machine or any machine connected to that router? Have you tested the speed from the router itself? Some routers have an option for a speedtest originating from them, rather than transferring the data over the internet and over the local (wireless) network. Point being that the problem might be in the local network. Have you checked for potential interference over wireless? Is it still slow if you put a cable directly to the router? – VLAZ Mar 6 at 10:32
  • There are a number of networking troubleshooting steps you can go through to figure out the speed problem but those are not security concerns. – schroeder Mar 6 at 11:29
  • @schroeder in my opinion, they should be done before putting this forward as a security concern. I don't think we should stating each troubleshooting with the question "could this be malware?". Especially if it's posted here. – VLAZ Mar 6 at 11:45
  • There is nothing in the post to suggest that traditional troubleshooting has not been done. It's just important to keep the network troubleshooting and musings about alternate issues separate. – schroeder Mar 6 at 11:50

It's not often I read a question and laugh out loud. I'm sorry your ISP is not helping you. Their response is funny. IF they can infallibly detect a virus, then they should also have the ability to respond to it.

A virus on the router could certainly copy information and inspect your traffic and not have any other effect. This might slow down your speed. Stealthy viruses are very, very common.

Some malware has no other goal but to disrupt service. This is known as a Denial-of-Service attack. I have not seen malware in years (a decade?) that just slows your network down a little just to be annoying.

Anti-virus on your computer will not help if the virus is on the router. You would need to reset your router to factory settings to remove any malware. That should have been your ISP's first recommendation.

  • It's been my experience ISP's worldwide (especially here in 'Murica) are known for having terrible customer service, being poorly trained, and rarely providing the throughput they claim to provide. Trust me, I've worked for 3 before heading to open (non-ISP) waters. – SomeGuy Mar 6 at 16:31
  • Note that malware on a router could hijack the factory reset functionality. – forest Mar 7 at 9:06

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