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- From: Corinna Vinschen <corinna-cygwin at cygwin dot com>
- To: cygwin-announce at cygwin dot com
- Date: Fri, 01 Mar 2019 22:20:27 +0100
- Subject: openssl 1.0.2r-1
- Reply-to: The Cygwin Mailing List <cygwin at cygwin dot com>
The following packages have been uploaded to the Cygwin distribution:
The OpenSSL toolkit provides support for secure communications between
machines. OpenSSL includes a certificate management tool and shared
libraries which provide various cryptographic algorithms and protocols.
Changes between 1.0.2q and 1.0.2r [26 Feb 2019]
*) 0-byte record padding oracle
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).
This issue was discovered by Juraj Somorovsky, Robert Merget and Nimrod
Aviram, with additional investigation by Steven Collison and Andrew
Hourselt. It was reported to OpenSSL on 10th December 2018.
*) Move strictness check from EVP_PKEY_asn1_new() to EVP_PKEY_asn1_add0().
Changes between 1.0.2p and 1.0.2q [20 Nov 2018]
*) Microarchitecture timing vulnerability in ECC scalar multiplication
OpenSSL ECC scalar multiplication, used in e.g. ECDSA and ECDH, has been
shown to be vulnerable to a microarchitecture timing side channel attack.
An attacker with sufficient access to mount local timing attacks during
ECDSA signature generation could recover the private key.
This issue was reported to OpenSSL on 26th October 2018 by Alejandro
Cabrera Aldaya, Billy Brumley, Sohaib ul Hassan, Cesar Pereida Garcia and
*) Timing vulnerability in DSA signature generation
The OpenSSL DSA signature algorithm has been shown to be vulnerable to a
timing side channel attack. An attacker could use variations in the signing
algorithm to recover the private key.
This issue was reported to OpenSSL on 16th October 2018 by Samuel Weiser.
*) Resolve a compatibility issue in EC_GROUP handling with the FIPS Object
Module, accidentally introduced while backporting security fixes from the
development branch and hindering the use of ECC in FIPS mode.