As I write this, RSA has announced it experienced an attack on its RSA SecurID one-time password (OTP) products. You can see Art Coviello’s letter to RSA’s customers here. The letter is very light on the nature of the attacks and what was stolen. In the interest of full disclosure, I worked at RSA for six years until 2003.
RSA SecurID leverages a symmetric key algorithm to generate one-time passwords. The device stores the symmetric key (in SecurID speak – the “seed”) and passes it through the time-based algorithm. Voila: the passcode appears on the screen. The passcode is concatenated with the user’s static PIN (think ATM card PIN) to build the one-time password.
There are two items in the SecurID secret sauce: the algorithm and the seed. From a cryptography 101 perspective, algorithms should be public and keys should be private. Nevertheless, the SecurID algorithm is ostensibly “private”. We should not consider this algorithm secret and it is distributed more broadly than you would expect.
So the security of the SecurID system quite rightly rests with the seeds. When RSA ships OTP devices to its customers, it also ships a seed file, which contains all of the symmetric keys associated with the OTP devices in the order. The seed file is sent for both hardware- and software-based devices, and is loaded into the Authentication Manager. As an aside, many SecurID customers don’t protect these seeds adequately.
Let’s conjecture about the attack might look like. If the algorithm was stolen, RSA may not be happy about it, but I think the hoof prints are already visible outside the barn door. If any customer seed records were stolen (or the ability to create them based upon the device serial number), this is a significant attack that directly compromises customer SecurID deployments.
If the seeds have been stolen, one might argue that the user’s PIN will save the day; not so. First, the PIN is a weak password. Second, not all OTP devices have PINs. Devices that have not been distributed yet don’t have a PIN. Deployed tokens that will be redistributed to new users will have their PIN reset.
Now, we wait and learn more about the attack.
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