CVE-2019-1559 – 0-byte record padding oracle

https://notcve.org/view.php?id=CVE-2019-1559

If an application encounters a fatal protocol error and then calls SSL_shutdown() twice (once to send a close_notify, and once to receive one) then OpenSSL can respond differently to the calling application if a 0 byte record is received with invalid padding compared to if a 0 byte record is received with an invalid MAC. If the application then behaves differently based on that in a way that is detectable to the remote peer, then this amounts to a padding oracle that could be used to decrypt data. In order for this to be exploitable "non-stitched" ciphersuites must be in use. Stitched ciphersuites are optimised implementations of certain commonly used ciphersuites. Also the application must call SSL_shutdown() twice even if a protocol error has occurred (applications should not do this but some do anyway). • http://lists.opensuse.org/opensuse-security-announce/2019-03/msg00041.html http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00019.html http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00046.html http://lists.opensuse.org/opensuse-security-announce/2019-04/msg00047.html http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00049.html http://lists.opensuse.org/opensuse-security-announce/2019-06/msg00080.html http://www.securityfocus.com/bid/107174 https://access. • CWE-203: Observable Discrepancy CWE-325: Missing Cryptographic Step •