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If I verify the fingerprint of a self-signed SSL certificate on the client, can a man-in-the-middle attack still occur?

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You can create your own certificate authority (CA), and distribute the public CA cert to all the clients who will be connecting to a server with certs signed by that CA. Then they'll work just like any other certificate. Just make sure to guard the CA key. –  Patrick Mar 24 '12 at 2:40
    
@Patrick ejbca.org may be a good place to start for people who aren't familiar with running a CA already. Makes the process fairly easy. –  Chris S Mar 24 '12 at 14:22
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2 Answers

Only if they manage to actually reproduce the fingerprint, which is much, much harder.

The Fingerprint is actually the most reliable method of determining a certificate is what it should be. It's just ignored by just about everyone.

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A self signed certificate is just as "secure" as a CA issued certificate given the same cryptographic specifications. All the same vulnerabilities and strengths are there.

The only difference is that clients generally have a preconfigured list of trusted CAs and will not ask, where they'll always initially ask for self-signed. Which it sounds like you're already aware of.

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1. "All the same vulnerabilities and strengths are there." man-in-the-middle not applicable to vulnerabilities and strengths 2. You did answer on clearly asked question at all. Downvote, ace of diamonds –  Lazy Badger Mar 24 '12 at 4:40
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Erh, no he did answer the question correctly imo. I think you are the one that's talking bs. –  Lucas Kauffman Mar 24 '12 at 7:33
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@LazyBadger I don't think you understand security, perhaps you should read up on MITM attacks and how they can apply to HTTPS communication. My answer implies that using a self signed certificate makes it no more or less likely that a MITM attack can be performed. If you are having trouble understanding you should ask for help. –  Chris S Mar 24 '12 at 14:20
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