On 18/03/2009 22.39, Stefano Zanero wrote:
Can you think of an instance of attack where detecting this is important ?
If I were a bank, I would be pretty much unhappy to have 10 bogus requests per second that consume the bandwidth, CPU cycles, and system memory, because the web server is allocating space to store the POST body, by slowly sending up to 248Kb (sometimes it took 1 minute). They do care about availability, and this is clearly a DoS. Besides, it's true that a rate of 10 requests per second it's nothing...but since the requests were coming from more than 50 different countries, I don't expect to be that difficult to increase the rate by infecting new hosts. Then you can argue that the attacker can use something like ABCDEFGHILMN... instead of AAAAAAAAAAAAA..., and things would get tough again. But I guess you know what would be my answer, given that this attack has been detected with an anomaly-based NIDS ;)
-- Damiano Bolzoni [email protected] Homepage http://dies.ewi.utwente.nl/~bolzonid/ PGP public key http://dies.ewi.utwente.nl/~bolzonid/public_key.asc Skype ID: [email protected] Distributed and Embedded Security Group - University of Twente P.O. Box 217 7500AE Enschede, The Netherlands Phone +31 53 4892477 Mobile +31 629 008724 ZILVERLING building, room 3013
