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An unsecured network doesn’t help an attacker gain your TOTP and password unless you’re using a website without HTTPS or that otherwise messes up by putting the

An unsecured network doesn’t help an attacker gain your TOTP and password unless you’re using a website without HTTPS or that otherwise messes up by putting the credentials as query parameters. The most an attacker might be able to view is the addresses of the sites you are connecting to.

tialaramex 3y ago
> The most an attacker might be able to view is the addresses of the sites you are connecting to. With TLS 1.2 or earlier the attacker can almost certainly discern the real DNS name of the site you're connecting to, in TLS 1.3 this is merely likely (and ECH might some day largely eliminate this risk) but not certain depending on how you connect. In practice your client hates wasting bandwidth and so precise size measurements are also surprisingly effective. If six people who I'm snooping watch movies from the Fast & Furious franchise on a streaming service and one watches "The Imitation Game" I can tell them apart with more or less 100% reliability. If they all read Wikipedia, six looking at stuff about dinosaurs and one reading about the Senate Intelligence Committee report on CIA torture, I can tell again. Clients (e.g. your web browser) could do more to hamper this, but they do almost nothing. For example, suppose I'm sending an encrypted HTTP request with some data in it, and it'll fit easily into 4 Ethernet packets. I could pad that last packet so it's always full, and have the decryption step remove that padding for free but clients don't bother, so a bad guy can measure how long my data is to within maybe 16 bytes.
Tainnor 3y ago
Yes, you're correct. An unsecured network is not enough. A honeypot wifi that the attacker controls would work, though, because they could just perform a MITM attack and thus decrypt your TLS traffic.
- Chrisoaks 3y ago
  That’s not true either, as they won’t possess https certificates for whatever the domain is and your browser would flag/block you from continuing.
  - Tainnor 3y ago
    huh, if they can MITM your connection, then they can just forward the certificates from the real host.
    - Chrisoaks 3y ago
      They will be able to view the public certificate but will not be able to sign or decrypt anything because they do not have the corresponding private key, which is never sent over the wire. HTTPS protects against MITM attacks. When the owner of the domain originally obtained a certificate, the obtained signed attestation from a trusted provider that they were able to field requests to that domain. Those requests can come from anywhere and are not possible to MITM. This attestation pertains to a public key/private key pair.
      - Tainnor 3y ago
        You're right, I misremembered. Thanks for pointing it out.

tialaramex 3y ago

> The most an attacker might be able to view is the addresses of the sites you are connecting to. With TLS 1.2 or earlier the attacker can almost certainly discern the real DNS name of the site you're connecting to, in TLS 1.3 this is merely likely (and ECH might some day largely eliminate this risk) but not certain depending on how you connect. In practice your client hates wasting bandwidth and so precise size measurements are also surprisingly effective. If six people who I'm snooping watch movies from the Fast & Furious franchise on a streaming service and one watches "The Imitation Game" I can tell them apart with more or less 100% reliability. If they all read Wikipedia, six looking at stuff about dinosaurs and one reading about the Senate Intelligence Committee report on CIA torture, I can tell again. Clients (e.g. your web browser) could do more to hamper this, but they do almost nothing. For example, suppose I'm sending an encrypted HTTP request with some data in it, and it'll fit easily into 4 Ethernet packets. I could pad that last packet so it's always full, and have the decryption step remove that padding for free but clients don't bother, so a bad guy can measure how long my data is to within maybe 16 bytes.

Tainnor 3y ago

Yes, you're correct. An unsecured network is not enough. A honeypot wifi that the attacker controls would work, though, because they could just perform a MITM attack and thus decrypt your TLS traffic.

Chrisoaks 3y ago
That’s not true either, as they won’t possess https certificates for whatever the domain is and your browser would flag/block you from continuing.
- Tainnor 3y ago
  huh, if they can MITM your connection, then they can just forward the certificates from the real host.
  - Chrisoaks 3y ago
    They will be able to view the public certificate but will not be able to sign or decrypt anything because they do not have the corresponding private key, which is never sent over the wire. HTTPS protects against MITM attacks. When the owner of the domain originally obtained a certificate, the obtained signed attestation from a trusted provider that they were able to field requests to that domain. Those requests can come from anywhere and are not possible to MITM. This attestation pertains to a public key/private key pair.
    - Tainnor 3y ago
      You're right, I misremembered. Thanks for pointing it out.