[TimothyFitz]

The researchers uncovered an XML Signature Wrapping attack, which requires the attacker has access to the plaintext of a correctly authorized XML request sent to Amazon. Given that every client I know of uses https for EC2 APIS, this isn't what I would call a "Massive Security Flaw".

More details on XML Signature Wrapping here: http://clawslab.nds.rub.de/wiki/index.php/XML_Signature_Wrap...

[tptacek]

You should read their actual paper, esp. section 3.1 (last graf) and 3.2 (first 2 grafs). You've oversimplified the problem; there is a variant of the attack that doesn't require an XML signature, for instance.