POODLE (CVE-2014-3566)

POODLE, short for Padding Oracle On Downgraded Legacy Encryption, is CVE-2014-3566, a weakness in the design of SSL 3.0. It affects CBC-mode encryption in that obsolete protocol rather than TLS itself.

Disclosure

Google security engineers Bodo Möller, Thai Duong, and Krzysztof Kotowicz published the issue on October 14, 2014. Their advisory explained that a network attacker could induce a browser to retry a failed connection using SSL 3.0 when fallback was enabled.

Once SSL 3.0 had been selected, the protocol flaw could be used to calculate plaintext from encrypted traffic under suitable conditions. The published work identified HTTP cookies and other bearer tokens as examples of information at risk.

Response and legacy

Browser vendors and service operators moved to disable SSL 3.0. Google recommended TLS_FALLBACK_SCSV as a way to prevent attackers from inducing fallback while compatibility transitions were underway.

Timeline

• 2014-10-14Google publishes technical details of POODLE and recommends ending SSL 3.0 fallback.
• 2014-10Mozilla announces plans to disable SSL 3.0 in Firefox.