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Ask HN: How bad is it to use a self-signed SSL certificate?

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Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#51

Post by mindslight »

tptacek wrote: post #23
ctz wrote: post #20

If you are careful when generating your certificate (that is, careful to generate a subject certificate, and not a CA certificate) and can reliably distribute your certificate to all clients you are interested in , then self-signed certificates are usually much better than the public CA system . But actually achieving the pre-distribution step is pretty hard, and basically impossible over the internet. You can achiev…

A site claiming to offer cryptographic security when it is in fact not is, in reality, worse than a site that simply doesn't offer cryptographic security. Both those sites --- the SSL site and the non-SSL site --- aren't offering security. But only one of them is also being deceptive about it. However, you'll get no argument from me if you constrain your argument about dismal mis-design to browser UI/UX. The browser…

Unauthenticated SSL does provide security against passive attackers, which is what mass surveillance in developed countries is. If the NSA ever insists on widespread MITM of connections, we have much bigger problems.

I agree the UI needs to be properly worked out so that eg a bank can't be downgraded to an unauthenticated certificate.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#52

Post by mindslight »

lockes5hadow wrote: post #49
tptacek wrote: post #23

Earlier quoted context omitted.

A site claiming to offer cryptographic security when it is in fact not is, in reality, worse than a site that simply doesn't offer cryptographic security. Both those sites --- the SSL site and the non-SSL site --- aren't offering security. But only one of them is also being deceptive about it. However, you'll get no argument from me if you constrain your argument about dismal mis-design to browser UI/UX. The browser…

You have a point here. Perhaps the real solution is that we should make the browser throw a fit when someone tries to input a "password" into a page/authdialog that has no security as well.

Then the altered page just specifies that it is not a password field, and emulates it with javascript or whatever. So that could only work for sites where a password manager was used, assuming the user doesn't just go ahead and type it in themselves.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#53

Post by MyDogHasFleas »

simon_vetter wrote: post #41
MyDogHasFleas wrote: post #17

I don't know why you're bothering with SSL at all. Your use case is that your site is informational, it's intended to be open to anyone, there is no personal/customer information on it, and there's no authentication (everyone is anonymous). All adding HTTPS support will do is make it marginally harder for someone to spoof your site. And why is NSA surveillance a concern? Your site is wide open for anyone to see, with…

By sending data in plain text, your users are revealing their intent to retrieve the content hosted on the site, even though that content is public. That in itself may be considered a breach of privacy, as it exposes your users to passive capture and profiling. Also, accessing the content you are hosting might be considered legal in some countries but illegal in others, regardless of if it is public or not.

Good points, but I would argue that HTTPS provides little protection against this kind of access tracking.

Even if the site is HTTPS protected, a surveillance actor on the net would still be able to read the entire site, maybe to determine if the site has content worthy of tracking those who access it.

And, surveillance would still reveal that your IP address is accessing the site, and thus triggering something.

What HTTPS would protect is the specific URL path you are going after on the site, because that's in the HTTP GET which is part of the encrypted data traffic.

I guess you could say that maybe the site has some pages that are more sensitive than others, and revealing the exact URL paths you are accessing might set off a surveillance trigger that would otherwise not be noticed. But, the site in question is probably not like that.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#54

Post by yaur »

cowbell wrote: post #26
stcredzero wrote: post #15

Earlier quoted context omitted.

I agree with your answer, but I don't recall ever seeing a post mortem write-up of such an attack. So, if you know how MITM operates, tell me: How would the server operator ever know?

http://www.scmagazine.com/researchers-detect-ssl-mitm-attack... About 0.2% for Facebook is MITM. And they are not using self signed certificates.

I'm going to go out on a limb here and say that the vast majority of that 0.2% are people sitting behind corporate proxies with a fake CA cert installed and pushed out to workstations via Group Policy. A hostile (and targeted) MITM could remove or alter the JavaScript that posts the fingerprint back to the server in which case it would be very difficult to detect.

The problem with Self Signed Certs in a practical sense is that they enable a much broader range of attacks. Neither of them protect you from LEO and NSA. Neither of them protect you from the people that own and/or can run code on your PC. CA issued certs will protect you from the carder that is connected to the same public WiFi, but self signed certs wont.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#55

Post by MyDogHasFleas »

itistoday2 wrote: post #32
cjbprime wrote: post #2

It's terrible, because Man-In-The-Middle attacks are trivial and automatable. namecheap.com sells PositiveSSL certs for $9/year -- that's pretty cheap and easy.

> It's terrible, because Man-In-The-Middle attacks are trivial and automatable. It's actually both terrible and the best security you can get. - Terrible because today's browsers participate in a pay-for-insecurity model, where any CA certificate can be used to compromise any website on the internet (except for the tiny number of hard-coded/"pinned" certs that some browsers ship for their company's websites). Certifi…

Aw come on, all you have to do is let your users choose an icon of their favorite animal or sport, save that as an account preference, and show it to them while they enter their password. We don't need better certificate verification!

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#56

Post by yaur »

dvanduzer wrote: post #28
ckuehl wrote: post #7

Earlier quoted context omitted.

> It's good, because you have control over the certificate creation, and never have to share your private key. You will never have to share your private key when getting a certificate from a proper CA, either.

This is true, but you wouldn't believe the system-as-practiced by most large IT departments. edit: small IT departments, too. nobody really pays attention as long as the lock icon is green.

Can't speak to the state of this on Linux, but on Windows/IIS if you "just follow the wizard" and send the generated file to your CA it will not include the key.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#57

Post by hollerith »

MyDogHasFleas wrote: post #55
itistoday2 wrote: post #32

Earlier quoted context omitted.

> It's terrible, because Man-In-The-Middle attacks are trivial and automatable. It's actually both terrible and the best security you can get. - Terrible because today's browsers participate in a pay-for-insecurity model, where any CA certificate can be used to compromise any website on the internet (except for the tiny number of hard-coded/"pinned" certs that some browsers ship for their company's websites). Certifi…

Aw come on, all you have to do is let your users choose an icon of their favorite animal or sport, save that as an account preference, and show it to them while they enter their password. We don't need better certificate verification!

Yahoo did something very much like that about 5 or 6 years ago: inviting me to upload an image file, then telling me to make sure the image is present every time I log in.

I upload an image file; the next time I found myself at Yahoo's login prompt, the image file was there; the time after that, it was absent. It has not re-appeared since.

Just offering a data point: I don't know enough to have an opinion about the technique.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#58

Post by itistoday2 »

hollerith wrote: post #57
MyDogHasFleas wrote: post #55

Earlier quoted context omitted.

Aw come on, all you have to do is let your users choose an icon of their favorite animal or sport, save that as an account preference, and show it to them while they enter their password. We don't need better certificate verification!

Yahoo did something very much like that about 5 or 6 years ago: inviting me to upload an image file, then telling me to make sure the image is present every time I log in. I upload an image file; the next time I found myself at Yahoo's login prompt, the image file was there; the time after that, it was absent. It has not re-appeared since. Just offering a data point: I don't know enough to have an opinion about the t…

I think he was making a joke. Those pictures do nothing to prevent TLS MITM attacks.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#59

Post by couradical »

Spittie wrote: post #13

https://www.startssl.com/ gives out free SSL certificates. Just don't expect much on their part, given it's free. For example, they refused to reissue certificates for free after Heartbleed. Also you can't use them on commercial sites. otherwise https://www.gogetssl.com/ is probably as cheap as it gets.

Thank you for the gogetssl.com link. I've been looking for a multi-SAN/wildcard cert that wasn't insanely expensive.

Re: Ask HN: How bad is it to use a self-signed SSL certificate?

#60

Post by digitalchaos »

Spittie wrote: post #13

https://www.startssl.com/ gives out free SSL certificates. Just don't expect much on their part, given it's free. For example, they refused to reissue certificates for free after Heartbleed. Also you can't use them on commercial sites. otherwise https://www.gogetssl.com/ is probably as cheap as it gets.

If you read startssl'a justification on the free cert, you'll see that they charge in relation to the time they need to spend. A low level 1 year cert involves no human time. They don't have fully automated systems for revokes/reissues, so it's pretty lame for people to complain about them charging for it.
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