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MD5 for passwords Using salted md5 for passwords is a bad idea. Not because of MD5's cryptographic weaknesses, but because it's fast. This means that an attacker can try billions of candidate passwords per second on a single GPU. What you should use are deliberately slow hash constructions, such as scrypt, bcrypt and PBKDF2. Simple salted SHA-2 is good not ...


9

In a TLS handshake, the "Finished" messages contain a value which is a hash of all the handshake messages exchanged so far (for this handshake). If the attacker alters the ClientHello then the hash will not match: when the second handshake completes (the first and only handshake in the view of the client, the second handshake from the point of view of the ...


7

Marsh Ray's blog seems to be down at the minute, but you can read more on Eric Rescorla's blog (I'm using the same example application data here) or in this PDF (archive.org copy). The genuine client sends a Client Hello (GenCH) to the server, but this is intercepted by the MITM. The MITM keeps hold of it and starts its own handshake by sending a a Client ...


6

To complete @CodesInChaos' answer, MD5 is often used because of Tradition, not because of performance. People who deal with databases are not the same people as those who deal with security. They often see no problem in using weak algorithms (e.g. see the joke of an algorithm that MySQL was using for hashing passwords). They use MD5 because they used to use ...


4

Overview. This is referring to a design weakness associated with renegotiation in SSL that was discovered a few years ago. The extension is designed to close the vulnerability. Background. SSL allows clients who have an established SSL session with a server to request renegotiation of the session parameters: e.g., the ciphersuite, and other security ...


4

The problem is not in doing a renegotiation; it is in believing in security characteristics that the renegotiation does not provide. Renegotiation is making a new handshake while in the middle of a SSL/TLS connection. This is described in the standard, albeit not in very clear terms, especially when it comes to defining what guarantees renegotiation offer. ...


1

From my understanding the main point of the attack is, that the part of the browser responsible for checking the Same Origin Policy thinks it is connected to host A, while the part responsible for sending the appropriate client certificate thinks it is connected to host B because it got the certificate for this host in the renegotiation. This way the browser ...


1

During renegotiation an attacker can inject information into the connection. It is described in detail here.


1

I'm using salted hashes currently (MD5 salted hashes). If you are salting MD5 hashes, you definitely don't want to be using MD5. It sounds like you need to use PBKDF2 or bcrypt. As far as I know it's always been the algorithm of choice among numerous DBAs. That's not a compelling reason. I have worked with a lot of DBAs that are at least 5 ...



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