ZyXEL Information for VU#997481
Cryptographic libraries and applications do not adequately defend against timing attacks
ZyXEL's present implementations don't utilize RSA algorithm. So there is no related issue currently.
In the second quarter of 2003, ZyWALL will support RSA signatures for IKE authentication which has no security concerns to this vulnerability either. This is because when IKE authenticated with RSA signatures, the input data that is hashed contains random input from the owner of the private key. In this case there is no possibility for opponent to influence the input value to the private key operation and the attack will not work.
But ZyWALL will leverage an RSA blinding procedure at the first moment of the release which can prevent this vulnerability if necessary in the future. The blinding procedure consists of randomizing the input to the modular exponentiation part of the RSA private key operation. The timing of the RSA decryption is then random, and thus prevents timing analysis from revealing any key information.
So ZyXEL's devices are immune to this vulnerability, #997481 now and hereafter.
The vendor has not provided us with any further information regarding this vulnerability.
The CERT/CC has no additional comments at this time.
If you have feedback, comments, or additional information about this vulnerability, please send us email.