- *) config has been changed so that by default OPENSSL_NO_DEPRECATED is used.
- Access to deprecated functions can be re-enabled by running config with
- "enable-deprecated". In addition applications wishing to use deprecated
- functions must define OPENSSL_USE_DEPRECATED. Note that this new behaviour
- will, by default, disable some transitive includes that previously existed
- in the header files (e.g. ec.h will no longer, by default, include bn.h)
+ *) BN_mod_exp may produce incorrect results on x86_64
+
+ There is a carry propagating bug in the x86_64 Montgomery squaring
+ procedure. No EC algorithms are affected. Analysis suggests that attacks
+ against RSA and DSA as a result of this defect would be very difficult to
+ perform and are not believed likely. Attacks against DH are considered just
+ feasible (although very difficult) because most of the work necessary to
+ deduce information about a private key may be performed offline. The amount
+ of resources required for such an attack would be very significant and
+ likely only accessible to a limited number of attackers. An attacker would
+ additionally need online access to an unpatched system using the target
+ private key in a scenario with persistent DH parameters and a private
+ key that is shared between multiple clients. For example this can occur by
+ default in OpenSSL DHE based SSL/TLS ciphersuites. Note: This issue is very
+ similar to CVE-2015-3193 but must be treated as a separate problem.
+
+ This issue was reported to OpenSSL by the OSS-Fuzz project.
+ (CVE-2017-3732)
+ [Andy Polyakov]
+
+ *) Montgomery multiplication may produce incorrect results
+
+ There is a carry propagating bug in the Broadwell-specific Montgomery
+ multiplication procedure that handles input lengths divisible by, but
+ longer than 256 bits. Analysis suggests that attacks against RSA, DSA
+ and DH private keys are impossible. This is because the subroutine in
+ question is not used in operations with the private key itself and an input
+ of the attacker's direct choice. Otherwise the bug can manifest itself as
+ transient authentication and key negotiation failures or reproducible
+ erroneous outcome of public-key operations with specially crafted input.
+ Among EC algorithms only Brainpool P-512 curves are affected and one
+ presumably can attack ECDH key negotiation. Impact was not analyzed in
+ detail, because pre-requisites for attack are considered unlikely. Namely
+ multiple clients have to choose the curve in question and the server has to
+ share the private key among them, neither of which is default behaviour.
+ Even then only clients that chose the curve will be affected.
+
+ This issue was publicly reported as transient failures and was not
+ initially recognized as a security issue. Thanks to Richard Morgan for
+ providing reproducible case.
+ (CVE-2016-7055)
+ [Andy Polyakov]
+
+ *) OpenSSL now fails if it receives an unrecognised record type in TLS1.0
+ or TLS1.1. Previously this only happened in SSLv3 and TLS1.2. This is to
+ prevent issues where no progress is being made and the peer continually
+ sends unrecognised record types, using up resources processing them.