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137

Can you explain why browser security should be placed on the top priority ... Because the browser is processing lots of untrusted content from the internet. Of course, if you use any other programs which does this (like Mail client, maybe Office program, PDF reader) you should keep these updated too since vulnerabilities in these programs are a regular ...


88

If your adversary is a powerful nation-state threat actor, web PKI will not protect you. Nothing is preventing them from issuing their own certificate. In fact, many governments run their own certificate authorities, such as the US FPKI and affiliates. See a list of CAs currently trusted by Firefox: Government of France Government of Hong Kong (SAR), ...


86

No, your data is not safe from key loggers on a local computer. There isn't much more to say here, to be fair. A key logger will grab and save any key stroke entered. The tls (https) encryption happens "after" the driver from keyboard "sends" those key strokes to the browser, "through" the key logger. Even if encryption is being used and there isn't one ...


85

If you don't secure example.com and a user visits that site, a man-in-the-middle attacker can manipulate the traffic and keep the user on example.com, where he can intercept all traffic. It doesn't matter that your version of example.com redirects to https://www.example.com/. The attacker can change this behavior and offer a HTTP version of your site to the ...


75

How does that work? They seem use an In-the-middle SSL Bump proxy. First, it works as a transparent proxy, meaning it will silently redirect all HTTPS traffic to SSL Bump proxy servers. You have to install and accept the proxy's Certificate Authority cert to make this work. Once done, each SSL connection is made from your host to the SSL Bump Proxy with ...


68

Interesting question! I just so happen to have a browser full of test certs, and a number of test sites to connect to! Let's test this! (Skip to the bottom for a summary) Investigation Testing on Firefox Firefox loaded with certs, a test site that requires a TLS client cert, Wireshark. I restarted Firefox to get a clean session. Then I entered the URL ...


63

Google, the major search engine of the Internet (dwarfing both Bing and Yahoo), and the browser used by majority of Internet users, has been pushing for an HTTPS-only world by decreasing the page rank for sites that do not HTTPS, and adding a browser warning when a site is not secure. However, the ratio of HTTPS sites to not is still far too low to recommend ...


60

You should not close off port 80. Instead, you should configure your server to redirect HTTP port 80 to HTTPS port 443 in order to use TLS. You can optionally use HSTS (HTTP Strict Transport Security) to tell browsers to remember to only use TLS when connecting to your site in the future. There is nothing insecure about port 80 being open. Security issues ...


56

While CBC is fine in theory, there is always the risk that an improper implementation will subject the connection to padding oracle attacks. Time and time again, CBC implementations in TLS have shown themselves to be vulnerable, and each time an implementation is fixed, it seems yet another bug making padding oracle attacks feasible appears. Lucky Thirteen ...


46

However, in this scheme, couldn't an impostor just present the certificate after getting it from the real server? An impostor cannot present, and take advantage of, the real server's certificate unless it also has the matching private key. This is true whether the SAN DNS entry or IP entry are used to identify the certificate being presented.


43

Assuming you mean TLS instead of genuine SSL (which is far older and broken), it is absolutely fine to transmit the password in a POST request. This is standard and how virtually every major and secure web authentication service works. You just have to make sure that the TLS is configured properly. TLS mitigates all the attacks you are worried about. It uses ...


41

... change the public key in the certificate and send it to client. Digital signature is same, all the properties except public key are same. So how can browser understand the difference? The browser checks that the signature of the certificates fits the certificate. Since the public key is included in the signature and the public key is changed, the ...


38

Are there any known cases of HTTPS websites leaking the private key of their SSL certificate? Yes - the Heartbleed bug involved memory leaks out of the HTTP server such that: We attacked ourselves from outside, without leaving a trace. Without using any privileged information or credentials we were able steal from ourselves the secret keys used for ...


30

Simply put, after four new CBC-exclusive attacks have been revealed, all padding oracle attacks, they want to discourage it, as per a comment from the author of the update blogpost: We are only encouraging to move away from CBC based cipher suits after 4 new CBC based vulnerabilities. As of now, there is no grade change for CBC and servers can continue to ...


30

If you ignore the certificate warning the encryption still applied, but because it's an unauthenticated encryption, the encryption is useless against active adversary (an MITM adversary that can intercept and modify the data passing through it), as the active adversary can just reencrypt your connection. The best practice to use self signed certificate in ...


29

No public Certificate Authority (CA) will issue a certificate for a private IP address, such as the 192.168.x.x blocks. Because of that, I would expect that I would not see an HTTPS connection to a consumer-grade router in my network, and if I noticed such a connection (this assumes, of course, that I'd actually notice the lock icon when it shouldn't be ...


28

There is currently no real risk just based on the TLS protocol version for the end user when visiting a site which provides only TLS 1.0 (TLSv1) with a modern browser, i.e. a current version of Chrome, Firefox, Edge or chromium based browsers like Opera. Fortunately browser vendors today actually care about security and if TLS 1.0 would be too insecure it ...


25

At the end of the TLS negotiation (the "Finished" message), the client and the server take a hash of the entire conversation they've had so far, and they compare it. If it differs - as it would if someone performed a MitM attack on the certificate - then the connection is dropped. To quote RFC 5246: The Finished message is the first one protected with ...


24

HTTPS can't possibly fully protect your user input on an untrusted computer: The computer could have keylogger software installed. The keyboard could have firmware programmed to keylog you. There could be a hardware device between the computer and the keyboard recording keypresses. There could be screen recording software running. There could be a video ...


24

If it's an official service you are integrating with the provider should really have a valid, publicly signed certificate installed for the sake of security. Assuming that you need to continue on with your provider using a self signed certificate, the big difference between ignoring the certificate and adding it as trusted is the following scenario. This ...


24

Certificates don’t exist in isolation. To be trustworthy, a certificate must be signed by an issuer; these issuers are called Certificate Authorities. Each browser (or operating system) maintains their own list of a few hundred trusted CAs (called Root CAs) that it already knows and trusts; and your employer or school may have their own private issuing root ...


21

Not all the websites you visit have certificates. You can’t smell fishy websites. Certificate doesn’t mean the site isn’t trying to hack you. The browser is the biggest attack vector against your computer. It will tend to run unvetted JavaScript code at least, and god knows what else. It constantly processes data from untrusted sources.


18

Each of your statements is making a false assumption here: Most of the websites I visit have SSL certificate. This is great, but SSL/TLS only protects you against certain types of attacks. Pretty much, a site having a (valid) TLS certificate simply means that the owner of that website has in some way proven ownership of the domain name that is used to ...


18

Yes, they can MitM the traffic this way, using an internal certificate authority. There are two primary ways in which the MitM can work. The first is to simply turn the edge gateway into a proxy, whereby TLS connections are made from the gateway to the server, and the gateway then generates server certificates on the fly from an internal CA in order to ...


17

If you don't have a certificate for example.com, anyone trying to access that (without the www. part) on HTTPS will get an error, and very likely not a redirection to www.example.com. With browsers pushing HTTPS as default protocol more and more, this will become a growing issue. Many certificate authorities allow you to add multiple domain names in one ...


17

By importing a known good self-signed certificate where the private key is unique and not compromised, the connection is just as safe as a full global CA PKI signed certificate. Those are after all also simply stored and trusted at some point. The reason to get a PKI CA signed cert is one of practicality more than security; if you have to trust a self-...


17

Is the only protection here that Bob actually checks that the public key on the returned certificate matches what he originally sent in his request to the CA? If the public key was switched before the CA used it to create the certificate, then Bob's web site won't work at all. The private key, which he has kept safe, will only work with his original ...


16

Yes, the communication is still encrypted with self-signed certificates. Self-signed certificates can be made by you, but they also can be made by any attacker. If you insist on using self-signed certificates, I would advice you to mark the certificate as trusted, so that you get a warning if an active man-in-the-middle attack is happening. Creating your ...


15

The required cipher suites depends entirely on the clients that are expected to use the service. As SSL Server Test from Qualys SSL Labs is designed for testing publicly accessible web servers, we can assume this is a web application. All current versions of major browsers are able to handle TLS 1.2+ with the recommended cipher suites from RFC 7525, 4.2, ...


14

This article is poorly written. First, by this time, it's old news: the attack was made public over two months ago. Oddly there doesn't seem to have been a thread about this attack here before, but there was one on Cryptography Stack Exchange which you can read for an introduction to how the attack works. A second way in which this article is misleading is ...


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