ID

VAR-201602-0272

CVE

CVE-2015-3197

TITLE

OpenSSL re-uses unsafe prime numbers in Diffie-Hellman protocol

DESCRIPTION

ssl/s2_srvr.c in OpenSSL 1.0.1 before 1.0.1r and 1.0.2 before 1.0.2f does not prevent use of disabled ciphers, which makes it easier for man-in-the-middle attackers to defeat cryptographic protection mechanisms by performing computations on SSLv2 traffic, related to the get_client_master_key and get_client_hello functions. OpenSSL may generate unsafe primes for use in the Diffie-Hellman protocol, which may lead to disclosure of enough information for an attacker to recover the private encryption key. Network traffic encrypted using an RSA-based SSL certificate may be decrypted if enough SSLv2 handshake data can be collected. This is known as the "DROWN" attack in the media. OpenSSL is prone to a security-bypass vulnerability. Successfully exploiting this issue may allow attackers to perform unauthorized actions. This may lead to other attacks. Cisco Unified Computing System Central Software is prone to an arbitrary command-execution vulnerability. An attacker can exploit this issue to execute system commands on the underlying operating system. This issue being tracked by Cisco Bug ID CSCut46961. Description: Red Hat JBoss Web Server is a fully integrated and certified set of components for hosting Java web applications. It is comprised of the Apache HTTP Server, the Apache Tomcat Servlet container, Apache Tomcat Connector(mod_jk), JBoss HTTP Connector (mod_cluster), Hibernate, and the Tomcat Native library. 7.1) - ppc64, ppc64le, s390x, x86_64 3. 5.9 server) - i386, ia64, x86_64 3. - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Gentoo Linux Security Advisory GLSA 201601-05 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - https://security.gentoo.org/ - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Severity: Normal Title: OpenSSL: Multiple vulnerabilities Date: January 29, 2016 Bugs: #572854 ID: 201601-05 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Synopsis ======== Multiple vulnerabilities have been found in OpenSSL, allowing remote attackers to disclose sensitive information and complete weak handshakes. Affected packages ================= ------------------------------------------------------------------- Package / Vulnerable / Unaffected ------------------------------------------------------------------- 1 dev-libs/openssl < 1.0.2f >= 1.0.2f Description =========== Multiple vulnerabilities have been discovered in OpenSSL. Please review the upstream advisory and CVE identifiers referenced below for details. Workaround ========== There is no known workaround at this time. Resolution ========== All OpenSSL users should upgrade to the latest version: # emerge --sync # emerge --ask --oneshot --verbose ">=dev-libs/openssl-1.0.2f" References ========== [ 1 ] CVE-2015-3197 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2015-3197 [ 2 ] CVE-2016-0701 http://nvd.nist.gov/nvd.cfm?cvename=CVE-2016-0701 [ 3 ] OpenSSL Security Advisory [28th Jan 2016] http://openssl.org/news/secadv/20160128.txt Availability ============ This GLSA and any updates to it are available for viewing at the Gentoo Security Website: https://security.gentoo.org/glsa/201601-05 Concerns? ========= Security is a primary focus of Gentoo Linux and ensuring the confidentiality and security of our users' machines is of utmost importance to us. Any security concerns should be addressed to security@gentoo.org or alternatively, you may file a bug at https://bugs.gentoo.org. License ======= Copyright 2016 Gentoo Foundation, Inc; referenced text belongs to its owner(s). The contents of this document are licensed under the Creative Commons - Attribution / Share Alike license. http://creativecommons.org/licenses/by-sa/2.5 . -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ===================================================================== Red Hat Security Advisory Synopsis: Important: openssl security update Advisory ID: RHSA-2016:0303-01 Product: Red Hat Enterprise Linux Advisory URL: https://rhn.redhat.com/errata/RHSA-2016-0303.html Issue date: 2016-03-01 CVE Names: CVE-2015-0293 CVE-2015-3197 CVE-2016-0703 CVE-2016-0704 CVE-2016-0800 ===================================================================== 1. Summary: Updated openssl packages that fix multiple security issues are now available for Red Hat Enterprise Linux 6.2, 6.4, and 6.5 Advanced Update Support. Red Hat Product Security has rated this update as having Important security impact. Common Vulnerability Scoring System (CVSS) base scores, which give detailed severity ratings, are available for each vulnerability from the CVE links in the References section. 2. Relevant releases/architectures: Red Hat Enterprise Linux Server AUS (v. 6.2) - x86_64 Red Hat Enterprise Linux Server AUS (v. 6.4) - x86_64 Red Hat Enterprise Linux Server AUS (v. 6.5) - x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 6.2) - x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 6.4) - x86_64 Red Hat Enterprise Linux Server Optional AUS (v. 6.5) - x86_64 3. Description: OpenSSL is a toolkit that implements the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols, as well as a full-strength, general purpose cryptography library. A padding oracle flaw was found in the Secure Sockets Layer version 2.0 (SSLv2) protocol. An attacker can potentially use this flaw to decrypt RSA-encrypted cipher text from a connection using a newer SSL/TLS protocol version, allowing them to decrypt such connections. For more information, refer to the knowledge base article linked to in the References section. It was discovered that the SSLv2 servers using OpenSSL accepted SSLv2 connection handshakes that indicated non-zero clear key length for non-export cipher suites. An attacker could use a SSLv2 server using OpenSSL as a Bleichenbacher oracle. A denial of service flaw was found in the way OpenSSL handled SSLv2 handshake messages. This could result in weak SSLv2 ciphers being used for SSLv2 connections, making them vulnerable to man-in-the-middle attacks. (CVE-2015-3197) Red Hat would like to thank the OpenSSL project for reporting these issues. Upstream acknowledges Nimrod Aviram and Sebastian Schinzel as the original reporters of CVE-2016-0800 and CVE-2015-3197; David Adrian (University of Michigan) and J. Alex Halderman (University of Michigan) as the original reporters of CVE-2016-0703 and CVE-2016-0704; and Sean Burford (Google) and Emilia Käsper (OpenSSL development team) as the original reporters of CVE-2015-0293. For the update to take effect, all services linked to the OpenSSL library must be restarted, or the system rebooted. 4. Solution: Before applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258 5. Bugs fixed (https://bugzilla.redhat.com/): 1202404 - CVE-2015-0293 openssl: assertion failure in SSLv2 servers 1301846 - CVE-2015-3197 OpenSSL: SSLv2 doesn't block disabled ciphers 1310593 - CVE-2016-0800 SSL/TLS: Cross-protocol attack on TLS using SSLv2 (DROWN) 1310811 - CVE-2016-0703 openssl: Divide-and-conquer session key recovery in SSLv2 1310814 - CVE-2016-0704 openssl: SSLv2 Bleichenbacher protection overwrites wrong bytes for export ciphers 6. Package List: Red Hat Enterprise Linux Server AUS (v. 6.2): Source: openssl-1.0.0-20.el6_2.8.src.rpm x86_64: openssl-1.0.0-20.el6_2.8.i686.rpm openssl-1.0.0-20.el6_2.8.x86_64.rpm openssl-debuginfo-1.0.0-20.el6_2.8.i686.rpm openssl-debuginfo-1.0.0-20.el6_2.8.x86_64.rpm openssl-devel-1.0.0-20.el6_2.8.i686.rpm openssl-devel-1.0.0-20.el6_2.8.x86_64.rpm Red Hat Enterprise Linux Server AUS (v. 6.4): Source: openssl-1.0.0-27.el6_4.5.src.rpm x86_64: openssl-1.0.0-27.el6_4.5.i686.rpm openssl-1.0.0-27.el6_4.5.x86_64.rpm openssl-debuginfo-1.0.0-27.el6_4.5.i686.rpm openssl-debuginfo-1.0.0-27.el6_4.5.x86_64.rpm openssl-devel-1.0.0-27.el6_4.5.i686.rpm openssl-devel-1.0.0-27.el6_4.5.x86_64.rpm Red Hat Enterprise Linux Server AUS (v. 6.5): Source: openssl-1.0.1e-16.el6_5.16.src.rpm x86_64: openssl-1.0.1e-16.el6_5.16.i686.rpm openssl-1.0.1e-16.el6_5.16.x86_64.rpm openssl-debuginfo-1.0.1e-16.el6_5.16.i686.rpm openssl-debuginfo-1.0.1e-16.el6_5.16.x86_64.rpm openssl-devel-1.0.1e-16.el6_5.16.i686.rpm openssl-devel-1.0.1e-16.el6_5.16.x86_64.rpm Red Hat Enterprise Linux Server Optional AUS (v. 6.2): Source: openssl-1.0.0-20.el6_2.8.src.rpm x86_64: openssl-debuginfo-1.0.0-20.el6_2.8.x86_64.rpm openssl-perl-1.0.0-20.el6_2.8.x86_64.rpm openssl-static-1.0.0-20.el6_2.8.x86_64.rpm Red Hat Enterprise Linux Server Optional AUS (v. 6.4): Source: openssl-1.0.0-27.el6_4.5.src.rpm x86_64: openssl-debuginfo-1.0.0-27.el6_4.5.x86_64.rpm openssl-perl-1.0.0-27.el6_4.5.x86_64.rpm openssl-static-1.0.0-27.el6_4.5.x86_64.rpm Red Hat Enterprise Linux Server Optional AUS (v. 6.5): Source: openssl-1.0.1e-16.el6_5.16.src.rpm x86_64: openssl-debuginfo-1.0.1e-16.el6_5.16.x86_64.rpm openssl-perl-1.0.1e-16.el6_5.16.x86_64.rpm openssl-static-1.0.1e-16.el6_5.16.x86_64.rpm These packages are GPG signed by Red Hat for security. Our key and details on how to verify the signature are available from https://access.redhat.com/security/team/key/ 7. References: https://access.redhat.com/security/cve/CVE-2015-0293 https://access.redhat.com/security/cve/CVE-2015-3197 https://access.redhat.com/security/cve/CVE-2016-0703 https://access.redhat.com/security/cve/CVE-2016-0704 https://access.redhat.com/security/cve/CVE-2016-0800 https://access.redhat.com/security/updates/classification/#important https://access.redhat.com/articles/2176731 https://drownattack.com/ https://openssl.org/news/secadv/20160128.txt https://openssl.org/news/secadv/20160301.txt 8. Contact: The Red Hat security contact is <secalert@redhat.com>. More contact details at https://access.redhat.com/security/team/contact/ Copyright 2016 Red Hat, Inc. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iD8DBQFW1cFVXlSAg2UNWIIRAiHFAKCv4By3YintGgRYJJyhA7n3FrUn1wCfZHLr V2xviZUG2H9rWZyjayig0oY= =rw6Q -----END PGP SIGNATURE----- -- RHSA-announce mailing list RHSA-announce@redhat.com https://www.redhat.com/mailman/listinfo/rhsa-announce. (CVE-2015-3197) An integer overflow flaw, leading to a NULL pointer dereference or a heap-based memory corruption, was found in the way some BIGNUM functions of OpenSSL were implemented. Applications that use these functions with large untrusted input could crash or, potentially, execute arbitrary code. OpenSSL Security Advisory [1st March 2016] ========================================= NOTE: With this update, OpenSSL is disabling the SSLv2 protocol by default, as well as removing SSLv2 EXPORT ciphers. We strongly advise against the use of SSLv2 due not only to the issues described below, but to the other known deficiencies in the protocol as described at https://tools.ietf.org/html/rfc6176 Cross-protocol attack on TLS using SSLv2 (DROWN) (CVE-2016-0800) ================================================================ Severity: High A cross-protocol attack was discovered that could lead to decryption of TLS sessions by using a server supporting SSLv2 and EXPORT cipher suites as a Bleichenbacher RSA padding oracle. Note that traffic between clients and non-vulnerable servers can be decrypted provided another server supporting SSLv2 and EXPORT ciphers (even with a different protocol such as SMTP, IMAP or POP) shares the RSA keys of the non-vulnerable server. Recovering one session key requires the attacker to perform approximately 2^50 computation, as well as thousands of connections to the affected server. A more efficient variant of the DROWN attack exists against unpatched OpenSSL servers using versions that predate 1.0.2a, 1.0.1m, 1.0.0r and 0.9.8zf released on 19/Mar/2015 (see CVE-2016-0703 below). Users can avoid this issue by disabling the SSLv2 protocol in all their SSL/TLS servers, if they've not done so already. Disabling all SSLv2 ciphers is also sufficient, provided the patches for CVE-2015-3197 (fixed in OpenSSL 1.0.1r and 1.0.2f) have been deployed. Servers that have not disabled the SSLv2 protocol, and are not patched for CVE-2015-3197 are vulnerable to DROWN even if all SSLv2 ciphers are nominally disabled, because malicious clients can force the use of SSLv2 with EXPORT ciphers. OpenSSL 1.0.2g and 1.0.1s deploy the following mitigation against DROWN: SSLv2 is now by default disabled at build-time. Builds that are not configured with "enable-ssl2" will not support SSLv2. Even if "enable-ssl2" is used, users who want to negotiate SSLv2 via the version-flexible SSLv23_method() will need to explicitly call either of: SSL_CTX_clear_options(ctx, SSL_OP_NO_SSLv2); or SSL_clear_options(ssl, SSL_OP_NO_SSLv2); as appropriate. Even if either of those is used, or the application explicitly uses the version-specific SSLv2_method() or its client or server variants, SSLv2 ciphers vulnerable to exhaustive search key recovery have been removed. Specifically, the SSLv2 40-bit EXPORT ciphers, and SSLv2 56-bit DES are no longer available. Builds that are not configured with "enable-weak-ssl-ciphers" will not provide any "EXPORT" or "LOW" strength ciphers. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was reported to OpenSSL on December 29th 2015 by Nimrod Aviram and Sebastian Schinzel. The fix was developed by Viktor Dukhovni and Matt Caswell of OpenSSL. Double-free in DSA code (CVE-2016-0705) ======================================= Severity: Low A double free bug was discovered when OpenSSL parses malformed DSA private keys and could lead to a DoS attack or memory corruption for applications that receive DSA private keys from untrusted sources. This scenario is considered rare. This issue affects OpenSSL versions 1.0.2 and 1.0.1. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was reported to OpenSSL on February 7th 2016 by Adam Langley (Google/BoringSSL) using libFuzzer. The fix was developed by Dr Stephen Henson of OpenSSL. Memory leak in SRP database lookups (CVE-2016-0798) =================================================== Severity: Low The SRP user database lookup method SRP_VBASE_get_by_user had confusing memory management semantics; the returned pointer was sometimes newly allocated, and sometimes owned by the callee. The calling code has no way of distinguishing these two cases. Specifically, SRP servers that configure a secret seed to hide valid login information are vulnerable to a memory leak: an attacker connecting with an invalid username can cause a memory leak of around 300 bytes per connection. Servers that do not configure SRP, or configure SRP but do not configure a seed are not vulnerable. In Apache, the seed directive is known as SSLSRPUnknownUserSeed. To mitigate the memory leak, the seed handling in SRP_VBASE_get_by_user is now disabled even if the user has configured a seed. Applications are advised to migrate to SRP_VBASE_get1_by_user. However, note that OpenSSL makes no strong guarantees about the indistinguishability of valid and invalid logins. In particular, computations are currently not carried out in constant time. This issue affects OpenSSL versions 1.0.2 and 1.0.1. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was discovered on February 23rd 2016 by Emilia Käsper of the OpenSSL development team. Emilia Käsper also developed the fix. BN_hex2bn/BN_dec2bn NULL pointer deref/heap corruption (CVE-2016-0797) ====================================================================== Severity: Low In the BN_hex2bn function the number of hex digits is calculated using an int value |i|. Later |bn_expand| is called with a value of |i * 4|. For large values of |i| this can result in |bn_expand| not allocating any memory because |i * 4| is negative. This can leave the internal BIGNUM data field as NULL leading to a subsequent NULL ptr deref. For very large values of |i|, the calculation |i * 4| could be a positive value smaller than |i|. In this case memory is allocated to the internal BIGNUM data field, but it is insufficiently sized leading to heap corruption. A similar issue exists in BN_dec2bn. This could have security consequences if BN_hex2bn/BN_dec2bn is ever called by user applications with very large untrusted hex/dec data. This is anticipated to be a rare occurrence. All OpenSSL internal usage of these functions use data that is not expected to be untrusted, e.g. config file data or application command line arguments. If user developed applications generate config file data based on untrusted data then it is possible that this could also lead to security consequences. This is also anticipated to be rare. This issue affects OpenSSL versions 1.0.2 and 1.0.1. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was reported to OpenSSL on February 19th 2016 by Guido Vranken. The fix was developed by Matt Caswell of the OpenSSL development team. Fix memory issues in BIO_*printf functions (CVE-2016-0799) ========================================================== Severity: Low The internal |fmtstr| function used in processing a "%s" format string in the BIO_*printf functions could overflow while calculating the length of a string and cause an OOB read when printing very long strings. Additionally the internal |doapr_outch| function can attempt to write to an OOB memory location (at an offset from the NULL pointer) in the event of a memory allocation failure. In 1.0.2 and below this could be caused where the size of a buffer to be allocated is greater than INT_MAX. E.g. this could be in processing a very long "%s" format string. Memory leaks can also occur. The first issue may mask the second issue dependent on compiler behaviour. These problems could enable attacks where large amounts of untrusted data is passed to the BIO_*printf functions. If applications use these functions in this way then they could be vulnerable. OpenSSL itself uses these functions when printing out human-readable dumps of ASN.1 data. Therefore applications that print this data could be vulnerable if the data is from untrusted sources. OpenSSL command line applications could also be vulnerable where they print out ASN.1 data, or if untrusted data is passed as command line arguments. Libssl is not considered directly vulnerable. Additionally certificates etc received via remote connections via libssl are also unlikely to be able to trigger these issues because of message size limits enforced within libssl. This issue affects OpenSSL versions 1.0.2 and 1.0.1. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was reported to OpenSSL on February 23rd by Guido Vranken. The fix was developed by Matt Caswell of the OpenSSL development team. Side channel attack on modular exponentiation (CVE-2016-0702) ============================================================= Severity: Low A side-channel attack was found which makes use of cache-bank conflicts on the Intel Sandy-Bridge microarchitecture which could lead to the recovery of RSA keys. The ability to exploit this issue is limited as it relies on an attacker who has control of code in a thread running on the same hyper-threaded core as the victim thread which is performing decryptions. This issue affects OpenSSL versions 1.0.2 and 1.0.1. OpenSSL 1.0.2 users should upgrade to 1.0.2g OpenSSL 1.0.1 users should upgrade to 1.0.1s This issue was reported to OpenSSL on Jan 8th 2016 by Yuval Yarom, The University of Adelaide and NICTA, Daniel Genkin, Technion and Tel Aviv University, and Nadia Heninger, University of Pennsylvania with more information at http://cachebleed.info. The fix was developed by Andy Polyakov of OpenSSL. Divide-and-conquer session key recovery in SSLv2 (CVE-2016-0703) ================================================================ Severity: High This issue only affected versions of OpenSSL prior to March 19th 2015 at which time the code was refactored to address vulnerability CVE-2015-0293. s2_srvr.c did not enforce that clear-key-length is 0 for non-export ciphers. If clear-key bytes are present for these ciphers, they *displace* encrypted-key bytes. This leads to an efficient divide-and-conquer key recovery attack: if an eavesdropper has intercepted an SSLv2 handshake, they can use the server as an oracle to determine the SSLv2 master-key, using only 16 connections to the server and negligible computation. More importantly, this leads to a more efficient version of DROWN that is effective against non-export ciphersuites, and requires no significant computation. This issue affected OpenSSL versions 1.0.2, 1.0.1l, 1.0.0q, 0.9.8ze and all earlier versions. It was fixed in OpenSSL 1.0.2a, 1.0.1m, 1.0.0r and 0.9.8zf (released March 19th 2015). This issue was reported to OpenSSL on February 10th 2016 by David Adrian and J. Alex Halderman of the University of Michigan. The underlying defect had by then already been fixed by Emilia Käsper of OpenSSL on March 4th 2015. The fix for this issue can be identified by commits ae50d827 (1.0.2a), cd56a08d (1.0.1m), 1a08063 (1.0.0r) and 65c588c (0.9.8zf). Bleichenbacher oracle in SSLv2 (CVE-2016-0704) ============================================== Severity: Moderate This issue only affected versions of OpenSSL prior to March 19th 2015 at which time the code was refactored to address the vulnerability CVE-2015-0293. s2_srvr.c overwrite the wrong bytes in the master-key when applying Bleichenbacher protection for export cipher suites. This provides a Bleichenbacher oracle, and could potentially allow more efficient variants of the DROWN attack. This issue affected OpenSSL versions 1.0.2, 1.0.1l, 1.0.0q, 0.9.8ze and all earlier versions. It was fixed in OpenSSL 1.0.2a, 1.0.1m, 1.0.0r and 0.9.8zf (released March 19th 2015). This issue was reported to OpenSSL on February 10th 2016 by David Adrian and J. Alex Halderman of the University of Michigan. The underlying defect had by then already been fixed by Emilia Käsper of OpenSSL on March 4th 2015. The fix for this issue can be identified by commits ae50d827 (1.0.2a), cd56a08d (1.0.1m), 1a08063 (1.0.0r) and 65c588c (0.9.8zf). Note ==== As per our previous announcements and our Release Strategy (https://www.openssl.org/policies/releasestrat.html), support for OpenSSL version 1.0.1 will cease on 31st December 2016. No security updates for that version will be provided after that date. Users of 1.0.1 are advised to upgrade. Support for versions 0.9.8 and 1.0.0 ended on 31st December 2015. Those versions are no longer receiving security updates. References ========== URL for this Security Advisory: https://www.openssl.org/news/secadv/20160301.txt Note: the online version of the advisory may be updated with additional details over time. For details of OpenSSL severity classifications please see: https://www.openssl.org/policies/secpolicy.html . DH small subgroups (CVE-2016-0701) ================================== Severity: High Historically OpenSSL usually only ever generated DH parameters based on "safe" primes. More recently (in version 1.0.2) support was provided for generating X9.42 style parameter files such as those required for RFC 5114 support. The primes used in such files may not be "safe". Where an application is using DH configured with parameters based on primes that are not "safe" then an attacker could use this fact to find a peer's private DH exponent. This attack requires that the attacker complete multiple handshakes in which the peer uses the same private DH exponent. For example this could be used to discover a TLS server's private DH exponent if it's reusing the private DH exponent or it's using a static DH ciphersuite. OpenSSL provides the option SSL_OP_SINGLE_DH_USE for ephemeral DH (DHE) in TLS. It is not on by default. If the option is not set then the server reuses the same private DH exponent for the life of the server process and would be vulnerable to this attack. It is believed that many popular applications do set this option and would therefore not be at risk. OpenSSL before 1.0.2f will reuse the key if: - SSL_CTX_set_tmp_dh()/SSL_set_tmp_dh() is used and SSL_OP_SINGLE_DH_USE is not set. - SSL_CTX_set_tmp_dh_callback()/SSL_set_tmp_dh_callback() is used, and both the parameters and the key are set and SSL_OP_SINGLE_DH_USE is not used. This is an undocumted feature and parameter files don't contain the key. - Static DH ciphersuites are used. The key is part of the certificate and so it will always reuse it. This is only supported in 1.0.2. It will not reuse the key for DHE ciphers suites if: - SSL_OP_SINGLE_DH_USE is set - SSL_CTX_set_tmp_dh_callback()/SSL_set_tmp_dh_callback() is used and the callback does not provide the key, only the parameters. The callback is almost always used like this. Non-safe primes are generated by OpenSSL when using: - genpkey with the dh_rfc5114 option. This will write an X9.42 style file including the prime-order subgroup size "q". This is supported since the 1.0.2 version. Older versions can't read files generated in this way. - dhparam with the -dsaparam option. This has always been documented as requiring the single use. The fix for this issue adds an additional check where a "q" parameter is available (as is the case in X9.42 based parameters). This detects the only known attack, and is the only possible defense for static DH ciphersuites. This could have some performance impact. Additionally the SSL_OP_SINGLE_DH_USE option has been switched on by default and cannot be disabled. This could have some performance impact. It is possible to generate parameters using non "safe" primes, but this option has always been documented as requiring single use and is not the default or believed to be common. However, as a precaution, the SSL_OP_SINGLE_DH_USE change has also been backported to 1.0.1r. An update on DHE man-in-the-middle protection (Logjam) ==================================================================== A previously published vulnerability in the TLS protocol allows a man-in-the-middle attacker to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. OpenSSL added Logjam mitigation for TLS clients by rejecting handshakes with DH parameters shorter than 768 bits in releases 1.0.2b and 1.0.1n. This limit has been increased to 1024 bits in this release, to offer stronger cryptographic assurance for all TLS connections using ephemeral Diffie-Hellman key exchange

AFFECTED PRODUCTS