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(NOTE: I've read other similar questions, but I'm not at all certain about this, therefore I'm asking.)

I travel a lot, and I generally use public WiFi spots and hotels/hostels/boarding houses etc. access points.

I'm a reporter. Sometimes I send my communications to email services and websites which don't use SSL cryptography (no https, just http), and though I KNOW this is not smart, I have no alternative.

What I want to know is if someone locally sniffing the network could read what I send to unprotected (no https) websites. If I send multimedia, pictures, audios etc., can they see/listen to them? Can they see what sites exactly I'm loading?

If so, what would take them? Just being connected to the same network? Having direct access to the router?

Is there anything I can do about it?

Again, I'm talking about people using the same network, snooping locally, and thinking about the data just after it leaves my PC and after it leaves the end node.

Thank you!

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Yes. Your data can be spoofed. Using Tor browser without tor is not protecting you anyhow. Use VPN when connecting from untrusted access point. – Jakuje Jan 24 at 13:09

When you use Tor, all data is encrypted between your computer and the exit node. As long as the exit node isn't on the same network that you are on (very, very unlikely to occur), the data will be protected from the local network. Note that meta data such as the fact that you're using Tor and rough estimates of how much data you are communicating may be observable, but the contents of that data will not.

As you are talking about using unencrypted communication, the clear txt data will be completely exposed from the exit node onward. Perhaps the biggest threat here is of a malicious exit node snooping or even modifying your data.

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The focus of Tor is not privacy, but anonymity. When you use Tor, your traffic is protected under multiple layers of encryption as it bounces between relay nodes, before it finally reaches and is decrypted by the exit node. The exit node finally sends your traffic to the intended destination and the reply back to you through the Tor network.

This setup has the following implicatins:

  • You are protected against sniffing and tampering by the WiFi network operator. This is because the connection between you and the first Tor relay is encrypted.
  • You are NOT protected against sniffing and tampering by whatever Tor exit node you happen to be using. The exit node, by necessity, needs to be able to unwrap the layers of encryption in order to be able to forward your traffic to the website you are trying to reach. If the website does not use SSL, the exit node operator can read your traffic in the clear.
  • The exit node operator still will not know your real IP address or who you are due to the bouncing between relays. Nor will the website you are visiting know, as it will only see the IP address of the exit note. This is the main goal of Tor - to protect anonymity. HOWEVER, if send identifying information of any sort to the website in question, then this is no longer true.

Whether you should trust a random Tor exit node any more than a random WiFi access point is debatable. Ideally, you should be using VPN with a trusted VPN provider if your goal is privacy.

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Why do you feel that a VPN provider provides better privacy than Tor? Especially being that you likely have a not-very-private account with the VPN provider. – Neil Smithline Jan 24 at 16:43
    
@NeilSmithline Hence you need a "trusted" VPN provider. VPN might seem worse because the provider is in the same position as the Tor exit node and has the added advantage of knowing who you are, but the difference is that you can do your research to find a well-known VPN provider that does not do any monitoring or logging, rather than rely on the luck of the draw with Tor exit nodes. If you cannot trust any VPN providers, you can always set up your own VPN server from a safe location. So Tor has an anonymity advantage and VPN usually has a privacy advantage, but both are better than nothing. – tlng05 Jan 24 at 16:58
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You need a "trustworthy" VPN and I believe that is beyond people's ability to identify. You can't be sure that a nefarious organization hasn't totally infiltrated a VPN provider's infrastructure. But this fine point is off-topic for the OP as it strictly refers to local-network spoofing. – Neil Smithline Jan 24 at 17:05

Here's a reasonable metaphor (I think).

Imagine you're going to deliver a message to someone and you're gonna mail it on a postcard. That is, anyone who can get their hands on the postcard can read your message. Now, you pick 3 random citizens to help you—A, B, and C. You put C's address on an envelope and you put the postcard inside. Then you put B's address on another envelope and you put the first envelope inside that. Then you put A's address on a final envelope and put the second envelope inside. Like Russian dolls, there's a postcard inside an envelope, inside and envelope, inside an envelope. You post it to A. A gets it, tears off the envelope and throws it away. Then she posts it to B. B gets it, tears off and discards the envelope, and posts it to C. C gets it (and this is the critical bit), tears off and discards the final envelope, and then C drops that postcard in her local postbox and the postcard gets delivered normally by the mail.

Anybody who can read that postcard (the mailman, people at the recipient's house, etc.) can see what you wrote. The only thing the envelope monkey business did for you was hide what postcode (IP address) the postcard (internet connection) originated from.

Now imagine you get a tamper-evident, opaque envelope instead of a postcard. This is an HTTPS connection. Run the whole thing again. In this case, people can still see that the recipient got a tamper-evident, opaque envelope (an SSL connection) but they can't tell what was inside it. And thanks to Tor, it's not obvious where it truly originated from, either.

So Tor simply hides where things came from. If they were unprotected to start with, they're still unprotected when they get there.

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Fundamentally your metaphor is right, except that Tor is not only about routing, the messages are encrypted so the envelope are already "tamper-evident, opaque envelope": only the recipient can open an envelope destined to him. The only issue therefore remains with the final element of the chain, C in your example, since it is the one who will have access to the actual postcard content and would therefore be in position to read/modify the card or its answer (or even to write a purely fake answer). A and B only have access to secured envelopes and not to the postcard. – WhiteWinterWolf Jan 24 at 17:49
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That's why I gave the example that people in my house who can read my post can read a postcard. Just like anyone who can read the network at the destination can read HTTP that was protected by Tor. Remember the OP's original question was about whether someone locally sniffing could read things protected by Tor that were HTTP otherwise. My point is that, while Tor protects you from the guy in the same coffee shop, it doesn't protect the content elsewhere (e.g., the ISP serving the HTTP web site). I wasn't highlighting C as a risk. Rather the end recipient and its network. – Paco Hope Jan 24 at 20:49

This is half speculative but worth a consideration. While it is certainly possible to snoop on traffic the chances anyone will bother in general is very small.

On the other hand if you specifically are a target then your laptop will be bugged and this is what I would be much more worried about. How's your personal opsec?

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I'm not sure I agree. The OP's post was that he sits in public places using public Wifi. While someone might not be targeting him specificially and following him around, those are absolutely the most likely places that someone will be sniffing the WiFi looking for stuff. There is no more likely situation for having your traffic sniffed than using a public WiFi. – Paco Hope Jan 28 at 11:05

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