* Posts by mikewood_sophos

1 post • joined 6 Oct 2009

DDoS attack rains down on Amazon cloud

mikewood_sophos

Combat DDoS at the source

Although Amazon "uses standard DDoS-fighting techniques such as syn cookies and connection limits" and also "maintains internal bandwidth which exceeds its provider-supplied Internet bandwidth", their pipe has a finite size which can be filled with a large enough flood of unwanted packets - which can come from anywhere.

Hopefully, initiatives to filter malicious network traffic at its source (eg. http://www.darkreading.com/blog/archives/2009/09/dutch_isps_sign.html) will gain traction. Straight bandwidth flooding attacks, such as the ones that struck Bitbucket, are precisely the type of attack that can be curtailed with a simple packet symmetry filtering mechanism, situated close to the source of the malicious traffic.

Mike Wood

Threat Researcher

Sophos Inc.

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