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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal style='text-autospace:none'>Since I hinted at it earlier today, FWIW here is the news - <a href="https://www.openssl.org/~bodo/ssl-poodle.pdf">https://www.openssl.org/~bodo/ssl-poodle.pdf</a> <o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>Poodle stands for “Padding Oracle On Downgraded Legacy Encryption”. CVE-2014-3566 has been reserved for this protocol vulnerability (no additional information is available yet at <a href="http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3566">http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2014-3566</a>). <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>The attack works by interfering with the establishment of a TLS connection. A client will quickly downgrade to SSLv3, which uses either the RC4 stream cipher (subject to information leakage) or a block cipher in CBC mode (subject to information leakage via the Poodle attack). <o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>As I understand the explanation, the man-in-the-middle decrypts the block ciphers by first padding a block with known values and then chipping away until the secure cookie (or other authentication data) is fully decrypted. <o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal style='text-autospace:none'>If disabling SSLv3 is not feasible due to legacy system issues, the paper suggests a few mitigations, such as using TLS_FALLBACK_SCSV to prevent a downgrade in the first place.<o:p></o:p></p><p class=MsoNormal style='text-autospace:none'><o:p> </o:p></p><p class=MsoNormal>“This use of TLS_FALLBACK_SCSV will ensure that SSL 3.0 is used only when a legacy implementation is involved: attackers can no longer force a protocol downgrade. (Attacks remain possible if both parties allow SSL 3.0 but one of them is not updated to support TLS_FALLBACK_SCSV, provided that the client implements a downgrade dance down to SSL 3.0.) “<o:p></o:p></p></div></body></html>