Hashfails and corrupted downloads when retrieving files directly via ISP connection but things clear up when using a VPN

Question

I'm facing SSL errors when accessing websites (on computer and mobile same network) the error shows up randomly (only some times I got the error) but lately I noticed that most of my downloads are corrupted (Zip and EXE files) also a lot of HashFails on the Torrent files (like 20GB wasted for 5GB file) I am connecting to the ISP via an ADSL modem at home then via Wi-Fi to the PC.

How can I be certain that my ISP is causing the SSL errors and corrupted files?

I thought my PC is infected so I installed an Antivirus and an Anti-malware but got the same result, then after trying to install Fusion360 (Autodesk) where the installer download the rest of the files I got another SSL error I tried everything they suggested on the help page but no luck.

Finally I installed VPN software and magically all the errors are gone and the downloaded files are working, Fusion360 installed fine. All this is making me think that this must be my ISP messing up the internet connection for some reason. Is this possible?

For example is the error I get when installing Fusion360 :

ssl.SSLError: [SSL: DECRYPTION_FAILED_OR_BAD_RECORD_MAC] decryption failed or bad record mac (_ssl.c:2090)`

And this while installing numpy

Could not install packages due to an EnvironmentError: [SSL: DECRYPTION_FAILED_OR_BAD_RECORD_MAC] decryption failed or bad record mac (_ssl.c:2217)

And this is error on a website :

err_cert_authority_invalid.

Here is another :

ERR_SSL_PROTOCOL_ERROR

And this :

www.reddit.com sent an invalid response. ERR_SSL_PROTOCOL_ERROR

there's no option to view the certificate, but once I reload the page I can access the site and can see the certificate details

also this :

Attackers might be trying to steal your information from m.facebook.com NET::ERR_CERT_AUTHORITY_INVALID

This on Facebook also and I did get the certificate

Here is what i can find on the ADSL section of the modem :

The ADSL BER test completed successfully.
Test Time (sec): 20 Total
Transferred Bits: 0x00000000046C1400
Total Error Bits: 0x0000000000000000
Error Ratio: 0.00e+00

and this ADSL STATICS :

Answer 1

Wild guess but this doesn't sound like intentional ISP meddling, and it's unlikely to be encryption-related.

Either there is some kind of major interference/data corruption between you and the ISP (which your VPN app hides by retransmitting corrupted packets instead of failing), or between the ISP and one of their upstreams (which the VPN just happens to route around).

Log in to your ADSL modem and check its DSL status page – error counts, signal/noise ratio, etc.

Either way, given that it happens on multiple devices on the same network, I'd contact the ISP's tech support.

Answer 2

There are a few reason for SSL errors aside from tampering - for example, is your computer's clock set correctly? If it's on the edge of a tolerance, then you could get occasional issues. But given that you're also having issues with BitTorrent, the problem isn't likely to be so confined - BitTorrent is a controversial technology, and I wouldn't be surprised if certain ISPs attempt to influence or dissuade users.

However... From the your description and the information you've provided, I think you're probably not far off-base with laying suspicions on your ISP. Are you willing / able to name them? If they hold a monopoly over any area then it's likely others will be experiencing issues too.

The ADSL link is fine:

• The BER (Bit Error Rate) during a test was zero...
• SNR margins of 38.2 dB and 8.5 dB are fine (down / up)
• Attenuation of 7 dB and 0.4 dB are fine (down / up)
• Given that the line probing has established an attainable rate of ~24.8 Mb/s downstream, and you've sync'd at 4 Mb/s, you are well within the margins (is your service capped at 4 Mb/s?)
• Few or no frame errors, zero uncorrectable errors