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Does it matter?Does it matter?Posted Aug 19, 2011 23:49 UTC (Fri) by pflugstad (subscriber, #224)In reply to: Does it matter? by njs Parent article: Unpredictable sequence numbers
I think you missed epa's point.
Even being able to predict TCP sequence numbers does not allow you to inject traffic into an existing SSH or SSL (https) connection. Both protocols encrypt the data and have integrity checks over the data, so if you injected data, it would fail to decrypt and/or fail the integrity checks.
So the worst that you can probably do if you can predict TCP sequence numbers is force the connection to be reset - packets with an invalid TCP sequence number would be discarded - if the seq num is valid, then SSL/SSH would flag it and abort the connection.
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Does it matter? Posted Aug 20, 2011 1:36 UTC (Sat) by njs (guest, #40338) [Link]
Yes, but I also use protocols like HTTP that don't have cryptographic integrity guarantees... and those protocols are more at risk if TCP sequence numbers are predictable than if they aren't, which is why TCP sequence numbers matter beyond DoS attacks. Which was epa's question...
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