How dangerous is it to use Tor as SOCKS5 proxy for *.onion domains only (via PAC file) in a "normal" browser?

I am aware that there is risk that .onion sites

  • can still fingerprint me and/or determine my public IP address through WebRTC
  • can make my browser perform requests to non-.onion sites via JS/<link>s/etc (and with PAC configuration those will route through clearnet).

But these attack vectors don't really bother me; I use TOR just for ZLib and TPB and I've accessed them via clearnet before they were censored.

Are there any other dangers besides that?

  • Main reason I've asked this is this paragraph on official TOR site: "We strongly recommend against using Tor in any browser other than Tor Browser. Using Tor in another browser can leave you vulnerable without the privacy protections of Tor Browser." They are very ominous, but they don't specify why. That's scary. Mar 27, 2023 at 0:58
  • 1
    Do you care about anonymity, or do you just want to be able to access the site?
    – Steve
    Mar 27, 2023 at 1:33
  • @Steve, I mostly care about being able to access the site, and about leaking password/cookies of my account on that site to third parties. Mar 27, 2023 at 2:13
  • I'm not aware of any security issues with using a normal browser for only onion services. You won't get the privacy properties of Tor, but the security shouldn't be affected, especially if you're only using Tor for onion services.
    – Steve
    Mar 28, 2023 at 14:02

1 Answer 1


It's a proper way to use a PAC in your local and trusted environment, but it's not a panacea. If you have any doubt in the environment and it's members - just use a localhost-based setup. Yes , it does add some overhead, but it saves you from a way greater dangers over the network. The only exception for this type of cases: if you have a semi-trusted neighborhood and you do control the exiting proxy and you're using it in not SOCKS but a HTTPS mode with your custom CA enforced. For a CA in this case I do recommend easyRSA scripts. Yes, it will not stop censors from disrupting your connection - but it will keep you safe against the intrusions. This case is usual like in a campus network

  • "just use a localhost-based setup" - yes, I mean local PAC file and SOCKS proxy on localhost Mar 29, 2023 at 1:16
  • then it's safe. The reason is if your local host is hijacked that deep that PAC's are bypassed - then even having Tor on it with any setup is useless: you're experiencing a rootkit case in that situation
    – Alexey Vesnin
    Mar 29, 2023 at 16:00

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