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58

In a nutshell: SSL/TLS client and server agree to use some weak crypto. Well, turns out that weak crypto is weak. In more details: In SSL/TLS, the client sends a list of supported cipher suites, and the server chooses one. At the end of the initial handshake, some Finished messages are exchanged, encrypted and protected with the newly negotiated crypto ...


21

This message is Google trying to push people nilly-willy into the 21st century of cryptography. So they point and mock when they see "RC4" or "SHA-1". This does not mean that such algorithms can be broken immediately. Only that Google would find the world a better place (or possibly a googler place) if everybody were using algorithms more to their liking, ...


18

Logjam shouldn't really be called a "new" vulnerability - it's a rehash of FREAK which targets export-grade DH rather than export-grade RSA. Practical exploitation relies on the following flaws: The TLS protocol is vulnerable to having its key exchange protocol downgraded by an attacker. Servers are still supporting export-grade Diffie-Hellman (e.g. ...


11

If your infrastructure is tiny, much of the details of running a CA (e.g. CRLs and such) can probably be ignored. Instead all you really have to worry about is signing certificates. There's a multitude of tools out there that will manage this process for you. I even wrote one many years ago. But the one I recommend if you want something really simple is ...


7

From The First Few Milliseconds of an HTTPS Connection: The master secret is a function of the client and server randoms. master_secret = PRF(pre_master_secret, "master secret", ClientHello.random + ServerHello.random) Both the client and the server need to be able to calculate the master secret. Generating a ...


5

So I think I've interpreted your question correctly. If not, fire away in the comments. Confusingly there are several factors in diffie hellman: are you doing it over elliptic curves or not, what size group have you got (let's assume "strong" and "not strong") and whether you generate ephemeral private/public keypairs or not. The problem with logjam is ...


4

2FA will decrease the chance that an attacker can steal a complete set of login credentials because, as you point out, the second factor is likely limited by lifetime or a once-use policy. But 2FA will not affect snooping or session hijacking. So, while an attacker may find it more difficult to login as you, they can watch your communication stream and send ...


3

https://www.ssllabs.com/ssltest/analyze.html?d=uk.care.com&s=46.137.89.126 https://www.ssllabs.com/ssltest/analyze.html?d=uk.care.com&s=54.228.236.90 The padlock is yellow because you have a certificate that uses SHA-1 in the certificate chain and Google have declared war on SHA-1 certificates. Chrome uses the operating system's root CAs. If the ...


3

There is no way to do this simply. there are some tools that can help you to easily get started. like: XCA EJBCA openssl none of them are a full PKI aside from possibly EJBCA but thats not trivial to setup. XCA is a small frontend tool to get a graphical interface to generate,sign and revoke Certificates. EJBCA or Enterprise Java Beans Certificate ...


3

Disabling RC4 completely would be great in an ideal world, but unfortunately we don't live in an ideal world. If you do disable it, certain mobile and embedded devices may not be able to communicate with you. Keep in mind that IE on Windows XP can only use RC4 because the underlying cryptographic API (CAPI) on the system doesn't have AES. As for the risk, ...


2

I think you're asking the wrong question. To me, "How much will my users be inconvenienced?", is far less important than "How sensitive is the information on this server?", or "How much would I care if it got hacked?". Hardening a system usually leads to some inconvenience. The level of inconvenience you're willing to endure (and inflict on your users) ...


2

I will answer this in a two-level approach: General term answer and the specific SSL/TLS clarification in blockquotes. Public Key Cryptography (PKC) solves the problem of securely exchanging information without the need of previously agreeing upon a secret key. To be part of PKC, every agent needs to have a Private Key (which should only be kept by the ...


2

Logjam is a cipher downgrade attack where a man in the middle can trick the end points into using a weak cipher. A weak cipher would allow the man in the middle to easily decrypt intercepted traffic. As with all other cipher downgrade attacks the best way to prevent it is to disable weak ciphers in the first place. If weak ciphers are not available even a ...


2

If you truly wish to be a CA take heed of the security implications of doing so. The private key used to generate the root CA for your intranet should literally be locked in a safe. And access to said safe should be physically monitored. Using a self signed root CA forces your users to not only trust that you are performing due diligence with the safe ...


2

Whats wrong? The waring you are getting is about "Mixed-Mode" which is basically when some parts of a site are sent over HTTPS and others are sent over HTTP. Some people down play this as unimportant because "The important data is encrypted" and while in a sense they are correct it can still be a security risk. Browser generally flag it for two reason: ...


2

(Moved from comment to answer) On Firefox, I found 2 Security Warnings in the Console: Loading mixed (insecure) display content "http://julian.referata.com/w/images/background-normal.png" on a secure page Loading mixed (insecure) display content "http://juliancubillos.com/favicon.ico" on a secure page They are most likely the reason why a warning sign is ...


2

I just did a small audit if your site, here are my findings. ssllabs test report grade A which is good a curl -vvv https://www.jcwiki.website/wiki/Main_Page | grep "http:" yielded no results, also good. Opening the site in Google Chrome (Version 42.0.2311.152) incognito window yields a mixed content warning. I checked the development tools and the reason ...


2

Update May 2015: Facebook now uses HSTS. Good work. $ http -h get https://www.facebook.com Strict-Transport-Security: max-age=15552000; preload See also https://www.ssllabs.com/ssltest/analyze.html?d=facebook.com


1

Do the smoke test: (stolen from OpenSSL blog. (Archived here.)) openssl s_client -connect www.example.com:443 -cipher "EDH" | grep "Server Temp Key" The key should be at least 2048 bits to offer a comfortable security margin comparable to RSA-2048. Connections with keys shorter than 1024 bits may already be in trouble today. (Note: you need OpenSSL ...


1

I'm going to assume that you are talking about HSTS. HSTS is TOFU (Trust on first use). So from the second use onwards, you are protected. But what about that first use? I don't think there's a unified strategy. But here's some ideas: What works today HSTS Preloading: Use a browser that makes use of the HSTS preload lists. (Chrome, Firefox) And hope ...


1

It has been argued that an emailing client, using the POP3 protocol over SSL, will reconnect on a regular basis and send the authentication password at a predictable place within the flow, close to the beginning. Thus, if a RC4-based cipher suite is used, a passive attacker may simply observe and wait, so that the known small biases of RC4 gradually reveal ...


1

Some attacks (e.g. BEAST, CRIME) are only effective against HTTPS. Not really. The underlying problems of ciphers or of use of compression are not specific to HTTPS, only some features of HTTP made it possible to exploit these problems because you were able to add chosen plain text to the encryption etc. You might find exploits for other protocols which ...


1

Follow these instructions to configure a Windows Based CA. Since you are issuing client certificates, be aware that SHA2 hashes aren't supported on XP. The simple answer is to: Install AD Install an Enterprise CA on the Domain Controller Edit the Certificate Template to issue End User Certificates (set the permission for users to self-enroll, or go to a ...


1

The answer seems quite simple to me. The final decision however, depending on the context, may not be as simple as it implies the notion of trust. SSL is a protocol allowing you to establish a secure connection over an untrusted network. The usefulness of SSL in your case therefore lies in this question: Do you trust the network between the web server and ...


1

I designed an image as Short answers of questions: for reading texts of the image open image in new tab for more details go to my previous answer.



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