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Re: A pothole in ISAKMP/Oakley
On Tue, 15 Apr 1997, Hilarie Orman wrote:
> Maybe we are talking about different attacks. The requirement for AH
> and ESP SPI generation was there before there was key management. We
> should ask why. I'd guess that the worry has been that an attacker
> could predict the SPI sequence and insert bogus messages with valid
> SPI's into the traffic stream, forcing the recipient to go through at
> least the trouble of checking the hash if not also decrypting.
An attacker could only predict the SPI sequence if they could read the traffic
stream. If they can do this, then they can see actual SPIs and use these in
bogus packets. So why would AH and ESP require pseudorandom SPIs? (The current
drafts just say that the SPI is an arbitrary value.)
Norm
Norman Shulman Secure Computing Canada
Systems Developer Tel 1 416 813 2075
norm@border.com Fax 1 416 813 2001
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