FreeBSD Security Advisory – A vulnerability in the TLS protocol would allow a man-in-the-middle attacker to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. This vulnerability is also known as Logjam. When processing an ECParameters structure OpenSSL enters an infinite loop if the curve specified is over a specially malformed binary polynomial field. When verifying a signedData message the CMS code can enter an infinite loop if presented with an unknown hash function OID. Various other issues have also been addressed.
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 ============================================================================= FreeBSD-SA-15:10.openssl Security Advisory The FreeBSD Project Topic: Multiple OpenSSL vulnerabilities Category: contrib Module: openssl Announced: 2015-06-12 Affects: All supported versions of FreeBSD. Corrected: 2015-06-11 19:07:45 UTC (stable/10, 10.1-STABLE) 2015-06-12 07:23:55 UTC (releng/10.1, 10.1-RELEASE-p12) 2015-06-11 19:39:27 UTC (stable/9, 9.3-STABLE) 2015-06-12 07:23:55 UTC (releng/9.3, 9.3-RELEASE-p16) 2015-06-11 19:39:27 UTC (stable/8, 8.4-STABLE) 2015-06-12 07:23:55 UTC (releng/8.4, 8.4-RELEASE-p30) CVE Name: CVE-2015-1788, CVE-2015-1789, CVE-2015-1790, CVE-2015-1791 CVE-2015-1792, CVE-2015-4000 For general information regarding FreeBSD Security Advisories, including descriptions of the fields above, security branches, and the following sections, please visit <URL:https://security.FreeBSD.org/>. I. Background FreeBSD includes software from the OpenSSL Project. The OpenSSL Project is a collaborative effort to develop a robust, commercial-grade, full-featured Open Source toolkit implementing the Secure Sockets Layer (SSL v2/v3) and Transport Layer Security (TLS v1) protocols as well as a full-strength general purpose cryptography library. II. Problem Description A vulnerability in the TLS protocol would allow a man-in-the-middle attacker to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. This vulnerability is also known as Logjam [CVE-2015-4000]. When processing an ECParameters structure OpenSSL enters an infinite loop if the curve specified is over a specially malformed binary polynomial field. [CVE-2015-1788] X509_cmp_time does not properly check the length of the ASN1_TIME string and can read a few bytes out of bounds. In addition, X509_cmp_time accepts an arbitrary number of fractional seconds in the time string. [CVE-2015-1789] The PKCS#7 parsing code does not handle missing inner EncryptedContent correctly. [CVE-2015-1790] When verifying a signedData message the CMS code can enter an infinite loop if presented with an unknown hash function OID. [CVE-2015-1792] If a NewSessionTicket is received by a multi-threaded client when attempting to reuse a previous ticket then a race condition can occur, potentially leading to a double free of the ticket data. [CVE-2015-1791] The OpenSSL advisory also describes a problem that is identified as CVE-2014-8176, which is already fixed by an earlier FreeBSD Errata Notice, FreeBSD-EN-15:02.openssl. III. Impact A man-in-the-middle attacker may be able to downgrade vulnerable TLS connections using ephemeral Diffie-Hellman key exchange to 512-bit export-grade cryptography. [CVE-2015-4000]. On FreeBSD 10.1, the patch contains a countermeasure for clients by rejecting handshakes with DH parameters shorter than 768 bits. An attacker who is able to use a certificate to authenticate with a remote system perform denial of service against any system which processes public keys, certificate requests or certificates. [CVE-2015-1788]. This affects FreeBSD 10.1 only, as the problem was no longer exist in OpenSSL 0.9.8 series since July 2012. An attacker can use the CVE-2015-1789 issue by using specifically crafted certificates and CRLs of various sizes and potentially cause a segmentation fault, resulting in a DoS on applications that verify certificates or CRLs. An attacker who can create specifically crafted malformed ASN.1-encoded PKCS#7 blobs with missing content and trigger a NULL pointer dereference on parsing. [CVE-2015-1790]. Applications that decrypt PKCS#7 data or otherwise parse PKCS#7 structures from untrusted sources are affected. OpenSSL clients and servers are not affected. An attacker can perform denial of service against any system which verifies signedData messages using the CMS code. [CVE-2015-1792] An attacker may be able to crash multi-thread applications that supports resumed TLS handshakes. [CVE-2015-1791] IV. Workaround No workaround is available. V. Solution Perform one of the following: 1) Upgrade your vulnerable system to a supported FreeBSD stable or release / security branch (releng) dated after the correction date. 2) To update your vulnerable system via a binary patch: Systems running a RELEASE version of FreeBSD on the i386 or amd64 platforms can be updated via the freebsd-update(8) utility: # freebsd-update fetch # freebsd-update install 3) To update your vulnerable system via a source code patch: The following patches have been verified to apply to the applicable FreeBSD release branches. a) Download the relevant patch from the location below, and verify the detached PGP signature using your PGP utility. [FreeBSD 10.1] # fetch https://security.FreeBSD.org/patches/SA-15:10/openssl-10.1.patch # fetch https://security.FreeBSD.org/patches/SA-15:10/openssl-10.1.patch.asc # gpg --verify openssl-10.1.patch.asc [FreeBSD 9.3 and 8.4] # fetch https://security.FreeBSD.org/patches/SA-15:10/openssl-8.4.patch # fetch https://security.FreeBSD.org/patches/SA-15:10/openssl-8.4.patch.asc # gpg --verify openssl-8.4.patch.asc b) Apply the patch. Execute the following commands as root: # cd /usr/src # patch < /path/to/patch c) Recompile the operating system using buildworld and installworld as described in <URL:https://www.FreeBSD.org/handbook/makeworld.html>. Restart all deamons using the library, or reboot the system. VI. Correction details The following list contains the correction revision numbers for each affected branch. Branch/path Revision - ------------------------------------------------------------------------- stable/8/ r284286 releng/8.4/ r284295 stable/9/ r284286 releng/9.3/ r284295 stable/10/ r284285 releng/10.1/ r284295 - ------------------------------------------------------------------------- To see which files were modified by a particular revision, run the following command, replacing NNNNNN with the revision number, on a machine with Subversion installed: # svn diff -cNNNNNN --summarize svn://svn.freebsd.org/base Or visit the following URL, replacing NNNNNN with the revision number: <URL:https://svnweb.freebsd.org/base?view=revision&revision=NNNNNN> VII. References <URL:https://www.openssl.org/news/secadv_20150611.txt> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1788> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1789> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1790> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1791> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1792> <URL:https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-4000> The latest revision of this advisory is available at <URL:https://security.FreeBSD.org/advisories/FreeBSD-SA-15:10.openssl.asc> -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.1.4 (FreeBSD) iQIcBAEBCgAGBQJVeopGAAoJEO1n7NZdz2rnzhQP/Ak6el188Y+7QbEYVfCZ7eG8 BQLj5TMGHV5swSKVlPcEuBlMwTjpgB5Gqhc8luDS0eIAuJGdcMPSrZDdXxWQFtPf pbfIwp/ElFc7d6ut0Y8t6fFLJbhTOoHJpzTGkFRfJkjinGOx7OZQPeLJsxSubbnL JKugZ3diH6yk6IPMf9SvhO/kYXUF1VbXQvHNTnqgdhFVkgF6tK22Pkl2XoJ9EHbh vBXft1yJwiYlZ//DxZuScTUj1pHYzK3bOpg//REJMWCMj1RVwQr2EyDa0Q2cT02d eRnSZykXD69eybyzEck+BvwnUYYJICimnHuE5t78UIr0D/NWyOAZTQ99z5TID5aV HXkcil+1E/Q+xBB4+5UOOnESf6cmiWwewQOVvD26ZY39E6oJXvsrWnyxIuCG6DL9 sLtxB6iTYlTX5Civ/VJX8H7rFiw4UwMembthvGzck22026iHjplWM3GCWz0E8O3R PrXBHjAzNFawK3owNMxFSUFTuFw/qY7EEwJ3SKCEC+hoxcLOl26NMxrQKRIAUk+I MMOaZfvOh2uM19y9SJZz8+sqU8gIm7ihDm5fuSkO8kY0jdvLwyS9bXAejN/lZ6oJ TyfTDDyXDOdaPpnpQehh6vQV0NiaJ+WXfGhfiE8/G/t6b1E0LlCaaGJTpYkildGe vVCM4Nyx4S9WDFOi76ug =dyhg -----END PGP SIGNATURE-----
Quelle: Packet Storm Security