Attacks on SSL

One of the many functions of SSL is providing for encrypted communications. Many attacks on SSL are designed to break the encryption by discovering the secret key used. Remember that SSL uses symmetric key cryptography to provide encryption. This basically means that the client and server each share the same secret key that is used to both encrypt and decrypt the communications. If an attacker can discover this secret, he can decrypt the communications.

The way that this symmetric key is generated is important. In a basic sense, combining a random number with some mathematical computation might generate the secret key. The computation will remain the same and should produce a secret key that cannot be easily deduced. Because an attacker will most likely know what the computation is because it is part of the software and public knowledge, he will be more interested in finding out what the randomly generated number is. If he can figure out what the random number is, he can simply run it through the same computation to get the secret key.

As mentioned earlier, another attack is the man-in-the-middle attack. Although several different attacks are performed from this perspective, one of the simplest is for the attacker to impersonate both parties. The attacker tries to get into a position where he appears to you as the trusted party and appears to the trusted party as you. The attacker might then try to intercept communications during the early stages, when you are just starting to set up the SSL connection. He will present to you a fraudulent certificate for your trusted party that you might accept as valid. If he can get you to set up an SSL connection through him, he will have access to all of the information you are sending to the trusted party.