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100

A custom CA is required if you want to use https on your corporate intranet. 3rd party CAs can only give you certificates for public domains. They won't give you certificates for intranet.local or any other hostnames which are only routed in your own network. So when you want to have a certificate for your intranet or for the web interface of your own ...


65

It sounds like your issue is that this vulnerability is bigger than you know what to do with. The rules of responsible disclosure, as decribed here, say that you should contact the vendor and negotiate a period of time - between 1 week and 6 months, depending on the depth of the changes required - in which they can implement a patch, revoke and re-issue ...


64

This "Kaspersky Anti-Virus Personal Root Certificate" is the sign that your anti-virus is actively intercepting the connection, in effect running a Man-in-the-Middle attack. This can work because your anti-virus runs locally (on your computer) its own certification authority, and inserted the corresponding CA key in the "trusted store" used by your browsers ...


61

Yup. Yes. (If you consider "My company's admins can change my HTTP(s) traffic" compromise.) Except for some programs that pin their certificate use and fail if another certificate is used. That's pretty much the idea of SSL inspection: Open up SSL/TLS, do some anti-virus-scanning, close up SSL/TLS again. And in place of that "do some anti-virus-scanning" ...


45

You are right assuming the certificate is useless without the private key, so sending it in the mail is no big security risk and is common practice actually. The certificate is supposed to be public, connecting to your website would also provide me with your certificate, so no need to hack your email there. edit When starting the connection the server ...


38

You need to import the root certificate into the trust store for the browser. Once the browser knows you trust this root certificate, all certificates signed by this will show up as trusted. Note that this will only make the connection trusted for you, any others who don't have the root certificate installed will still receive an error.


35

The purpose of the warning is that by using HTTPS, there is an expectation of proper security, but a self-signed or expired certificate has vulnerabilities that the user needs to be aware of. The "risk" is that one thinks they are properly secured, but they are not fully secured, as opposed to HTTP, where one knows there is no encryption at all. There ...


33

Solved. The problem was indeed triggered by installing Apple Mavericks/ML Security Update 2015-004. As mentioned in this Apple release note, it included updates to the certificate trust policy. There was a duplicate certificate installed (with a wrong serial no.), removing it fixed the problem. The serial number for the cert as published by Apple matched ...


33

Such a claim is generally quite serious. While reaching out to the vendor in question is a responsible matter, you should certainly consider notifying the relevant root store security teams, since they are responsible for designing, evaluating, and applying the security controls to prevent this, and will likely need to directly work with the CA to ascertain ...


30

Self-signed certificates are inherently not trusted by your browser because a certificate itself doesn't form any trust, the trust comes from being signed by a certificate that EVERYONE trusts. Your browser simply doesn't trust your self-signed certificate as if it were a root certificate. To make your browser accept your certificate, go into your browsers ...


29

Yes, what you are getting in the zip file is exactly what every visitor to your site would get every time they start a TLS session - the public keys with certifying information. The private key is the only thing that should be kept hidden from unauthorized access.


27

Mostly yes, any CA in your trusted root, (or subordinates) can issue a cert for any DNS name. Name constraints and Enhanced Key Usage can be used to mitigate this, but they aren't enforced everywhere. DANE, Certificate Pinning, and Certificate transparency are a few projects that help protect from this risk.


27

Installing a root certificate on users browsers, and conducting a MiTM attack on employees is unfortunately a standard practice at many companies. There's a few ways you can detect this. One way is looking for a root CA cert installed on your computer and see if you don't recognize one of the CAs. This of course requires an in-depth knowledge of what ...


24

Certificates are signed and the cryptographic signature is verified; if the signature matches then the certificate contents are exactly as they were when the certificate was signed. This, of course, does not solve the problem, it merely moves it around. The complete structure is called a PKI. The certificates which are preinstalled in your computer (came ...


23

Congratulations! Sounds like a major find. First, generate some proof. The github.com SSL certificate sounds like a great start. Make sure you keep all the network traces you need to show exactly what happened. You need to determine if you broke any laws or T&Cs while doing this. If the CA does not have a bug bounty, you almost certainly did. In that ...


23

Security difference First, let's talk about SSL (now called TLS by the way), which adds the 'S' at the end of HTTPS and is in charge of "securing the communication". The clue to answer this question is indeed to fully understand what we mean by "securing the communication". SSL, no matter if it is a self-signed certificate which is being used or one signed ...


21

There is a standard for that, and, more generally, for all communications with a PKI. It is called CMP. Revocation requests are specified in section 5.3.9. Now, finding a PKI that actually implements CMP... this may be challenging.


19

CA signed certs are not actually more secure than self-signed certs, in the sense that the level of encryption is the same. But there is a big difference in the level of trust between the two. Visitors to a site using a self-signed cert have to trust that the cert was generated by the site owner, simply because the site says it is. There is no easy way to ...


18

When unsure, you can also contact CERT: https://forms.cert.org/VulReport/ They have experience in dealing with even very serious security vulnerabilities, and are generally considered a trusted party. At least they can confirm that your assessment of the vulnerability is correct, and document your part in finding it. While CERT generally advises you to ...


17

Can any CA sign any cert for any domain? In general, yes. Trusted root certs are trusted for anything under the root. If the answer is yes, what prevents having two different CAs creating a valid cert for the same domain? Nothing - it's completely legitimate for you, the owner of example.com, to go get a certificate for www.example.com issued by ...


17

Certificates are a matter of trust. CA are supposed to be trustful globaly so we can rely on them even if we don't know each other. In cases where you are communicating with only people you know or .... yourself, like when you are responsible of a network of different machines, you can choose to rely on yourself more than to rely on a CA that in fact, you ...


16

Google blogged about flagging Certificates using SHA-1 here -> Gradually sunsetting SHA-1 There's no reason to get a new certificate yet as Chrome won't be actually blocking the certificate just treated as “secure, but with minor errors”, I believe that some issuers are offering to reissue certificate but as always, YMMV.


15

It's prevented through legal (contractual) and not technical means. What happens if a CA creates an certificate which is not duly authorized by the legitimate domain owner: Time passes, with users unknowingly trusting the fraud. Somebody notices and reports it. Browser vendors remove that CA's root certificate from the next update to the trusted list All ...


15

There is nothing at all wrong with running your own internal certificate authority; the vast majority of large companies that I have interacted with have their own internal CA. Advantages The nominal cost of a cert becomes nearly zero when amortized over enough systems and users; when you purchase certificates from an external CA, this will never become ...


13

All certificates are signed in whole (protected against changes), so you can't change the name, or any other data inside it. The certificate of the server you connect to is signed by the issuer certificate, which in turn may be signed by other certificates higher up, this is the certificate chain. The top, aka root is signed by itself. If you make any ...


12

First of, CRL do not cover root CA. By definition, a root CA is a root: it has no issuer except itself. A CRL conveys revocation information, which is a way for a certificate issuer to announce that a previously issued certificate should be considered as invalid even though it looks fine and its signature is correct and everything. Thus, a CRL that talks ...


12

Does Google's decision mean that it would be prudent for me to also delete or disable the root CA from my machine? Dunno. Symantec ain't being too helpful. Theoretically it should not hurt but something seems to be broken in clients. Also: Vendors don't seem to agree on this. I've whipped up a quick script and parsed four trust stores (Apple, ...


11

Public Key Cryptography designates the class of cryptographic algorithms that includes asymmetric encryption (and its cousin key exchange) and digital signatures. In these algorithms, there are two operations that correspond to each other (encrypt -> decrypt, or sign -> verify) with the characteristic that one of the operations can be done by everybody while ...


11

Simply put, the webmaster of the site uploads the certificate to CloudFlare. See this article for details. The Keyless mode doesn't have this requirement. It uses an on premise key server instead, to provide the private key of the server. See the diagram here for details on how this works. For free accounts Cloudflare state in their blog: For all ...


11

Intentionally "spying" on yourself for debugging purposes, using proxy tools like Fiddler or Charles to capture https traffic. These tools are often used by mobile app developers, among others, to debug client-server communications. A root CA can be generated and installed on a mobile device, a computer set as that device's http proxy, and all web traffic, ...



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