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POODLE: SSL 3.0 Vulnerability
Last update on 20. October 2014 - 7:15.
A new SSLv3 vulnerability called POODLE (Padding Oracle On Downgraded Legacy Encryption) was published today. The vulnerability allows recovering plaintext, for example HTTP cookies, of a HTTPS connection.
Attackers require MitM (man-in-the-middle) access to the connection and must be able to force the client to perform special requests. This is usually done by injecting JavaScript.
Note that POODLE may also affect TLS 1.0 - 1.2 connections if both endpoints support SSLv3. A MiTM attacker can force both endpoints to use SSLv3 by running an SSL protocol downgrade attack. A new TLS option called TLS_FALLBACK_SCSV is now available with OpenSSL 1.0.1j to prevent protocol downgrade attacks. Unfortunately this option requires client support to be effective. The only browser currently supporting the feature is Google Chrome (since February 2014). Airlock therefore decided to completely deactivate SSLv3 in the corresponding hotfix.
Airlock provides hotfixes for all currently supported releases:
Note that by disabling SSLv3, very old clients like IE6 on Windows XP can no longer use HTTPS with Airlock. Newer clients support the successor protocol TLS and are not affected by this change.
A list of common clients/browers and their supported SSL version can be found in any Qualys SSL Report [2] in the section Handshake Simulation.