March 19th OpenSSL Vulnerabilities Overview

The pre-announced OpenSSL updates purport to address 13 vulnerabilities. Two of the vulnerabilities were graded as being of High severity by the OpenSSL project. The first, CVE-2015-0291 allows client connections to engage in a denial of service attack against servers running OpenSSL. The second high severity issue was the older CVE-2015-0204 where RSA connections could be silently degraded to export quality RSA, originally OpenSSL graded this as a low security vulnerability but reclassified this as a high severity vulnerability.

A number of vulnerabilities graded as moderate concern poor memory handling in OpenSSL that could lead to segfaults and other undesirable behavior, but one stood out. CVE-2015-0292 concerns OpenSSL's decoding of base64 data and decoding maliciously crafted Base64 data could lead to all kinds of mischief and the OpenSSL Project reports having corrected this in earlier versions of OpenSSL, but for some unfathomable reason is only just now referring to this as a security vulnerability.

Of the 13 announced vulnerabilities only 5 were applicable to the OpenBSD project's LibreSSL fork. The fork was originally started after the Heartbleed bug's unveiling due to OpenBSD contributors lamenting OpenSSL's use of custom memory handling functions that left OpenSSL impervious to many of the tools used by the OpenBSD project to locate and correct bugs.

The OpenSSL security advisory is available here or mirrored below:

OpenSSL Security Advisory [19 Mar 2015]
=======================================

OpenSSL 1.0.2 ClientHello sigalgs DoS (CVE-2015-0291)
=====================================================

Severity: High

If a client connects to an OpenSSL 1.0.2 server and renegotiates with an
invalid signature algorithms extension a NULL pointer dereference will occur.
This can be exploited in a DoS attack against the server.

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 users should upgrade to 1.0.2a.

This issue was was reported to OpenSSL on 26th February 2015 by David Ramos
of Stanford University. The fix was developed by Stephen Henson and Matt
Caswell of the OpenSSL development team.

Reclassified: RSA silently downgrades to EXPORT_RSA [Client] (CVE-2015-0204)
============================================================================

Severity: High

This security issue was previously announced by the OpenSSL project and
classified as "low" severity. This severity rating has now been changed to
"high".

This was classified low because it was originally thought that server RSA
export ciphersuite support was rare: a client was only vulnerable to a MITM
attack against a server which supports an RSA export ciphersuite. Recent
studies have shown that RSA export ciphersuites support is far more common.

This issue affects OpenSSL versions: 1.0.1, 1.0.0 and 0.9.8.

OpenSSL 1.0.1 users should upgrade to 1.0.1k.
OpenSSL 1.0.0 users should upgrade to 1.0.0p.
OpenSSL 0.9.8 users should upgrade to 0.9.8zd.

This issue was reported to OpenSSL on 22nd October 2014 by Karthikeyan
Bhargavan of the PROSECCO team at INRIA. The fix was developed by Stephen
Henson of the OpenSSL core team. It was previously announced in the OpenSSL
security advisory on 8th January 2015.

Multiblock corrupted pointer (CVE-2015-0290)
============================================

Severity: Moderate

OpenSSL 1.0.2 introduced the "multiblock" performance improvement. This feature
only applies on 64 bit x86 architecture platforms that support AES NI
instructions. A defect in the implementation of "multiblock" can cause OpenSSL's
internal write buffer to become incorrectly set to NULL when using non-blocking
IO. Typically, when the user application is using a socket BIO for writing, this
will only result in a failed connection. However if some other BIO is used then
it is likely that a segmentation fault will be triggered, thus enabling a
potential DoS attack.

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 users should upgrade to 1.0.2a.

This issue was reported to OpenSSL on 13th February 2015 by Daniel Danner and
Rainer Mueller. The fix was developed by Matt Caswell of the OpenSSL development
team.

Segmentation fault in DTLSv1_listen (CVE-2015-0207)
===================================================

Severity: Moderate

The DTLSv1_listen function is intended to be stateless and processes the initial
ClientHello from many peers. It is common for user code to loop over the call to
DTLSv1_listen until a valid ClientHello is received with an associated cookie. A
defect in the implementation of DTLSv1_listen means that state is preserved in
the SSL object from one invocation to the next that can lead to a segmentation
fault. Errors processing the initial ClientHello can trigger this scenario. An
example of such an error could be that a DTLS1.0 only client is attempting to
connect to a DTLS1.2 only server.

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 DTLS users should upgrade to 1.0.2a.

This issue was reported to OpenSSL on 27th January 2015 by Per Allansson. The
fix was developed by Matt Caswell of the OpenSSL development team.

Segmentation fault in ASN1_TYPE_cmp (CVE-2015-0286)
===================================================

Severity: Moderate

The function ASN1_TYPE_cmp will crash with an invalid read if an attempt is
made to compare ASN.1 boolean types. Since ASN1_TYPE_cmp is used to check
certificate signature algorithm consistency this can be used to crash any
certificate verification operation and exploited in a DoS attack. Any
application which performs certificate verification is vulnerable including
OpenSSL clients and servers which enable client authentication.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0 and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was discovered and fixed by Stephen Henson of the OpenSSL
development team.

Segmentation fault for invalid PSS parameters (CVE-2015-0208)
=============================================================

Severity: Moderate

The signature verification routines will crash with a NULL pointer
dereference if presented with an ASN.1 signature using the RSA PSS
algorithm and invalid parameters. Since these routines are used to verify
certificate signature algorithms this can be used to crash any
certificate verification operation and exploited in a DoS attack. Any
application which performs certificate verification is vulnerable including
OpenSSL clients and servers which enable client authentication.

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 users should upgrade to 1.0.2a

This issue was was reported to OpenSSL on 31st January 2015 by Brian Carpenter
and a fix developed by Stephen Henson of the OpenSSL development team.

ASN.1 structure reuse memory corruption (CVE-2015-0287)
=======================================================

Severity: Moderate

Reusing a structure in ASN.1 parsing may allow an attacker to cause
memory corruption via an invalid write. Such reuse is and has been
strongly discouraged and is believed to be rare.

Applications that parse structures containing CHOICE or ANY DEFINED BY
components may be affected. Certificate parsing (d2i_X509 and related
functions) are however not affected. OpenSSL clients and servers are
not affected.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0
and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was discovered by Emilia Käsper and a fix developed by
Stephen Henson of the OpenSSL development team.

PKCS7 NULL pointer dereferences (CVE-2015-0289)
===============================================

Severity: Moderate

The PKCS#7 parsing code does not handle missing outer ContentInfo correctly.
An attacker can craft malformed ASN.1-encoded PKCS#7 blobs with
missing content and trigger a NULL pointer dereference on parsing.

Applications that verify PKCS#7 signatures, decrypt PKCS#7 data or
otherwise parse PKCS#7 structures from untrusted sources are
affected. OpenSSL clients and servers are not affected.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0
and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was reported to OpenSSL on February 16th 2015 by Michal
Zalewski (Google) and a fix developed by Emilia Käsper of the OpenSSL
development team.

Base64 decode (CVE-2015-0292)
=============================

Severity: Moderate

A vulnerability existed in previous versions of OpenSSL related to the
processing of base64 encoded data. Any code path that reads base64 data from an
untrusted source could be affected (such as the PEM processing routines).
Maliciously crafted base 64 data could trigger a segmenation fault or memory
corruption. This was addressed in previous versions of OpenSSL but has not been
included in any security advisory until now.

This issue affects OpenSSL versions: 1.0.1, 1.0.0 and 0.9.8.

OpenSSL 1.0.1 users should upgrade to 1.0.1h.
OpenSSL 1.0.0 users should upgrade to 1.0.0m.
OpenSSL 0.9.8 users should upgrade to 0.9.8za.

The fix for this issue can be identified by commits d0666f289a (1.0.1),
84fe686173 (1.0.0) and 9febee0272 (0.9.8). This issue was originally reported by
Robert Dugal and subsequently by David Ramos.

DoS via reachable assert in SSLv2 servers (CVE-2015-0293)
=========================================================

Severity: Moderate

A malicious client can trigger an OPENSSL_assert (i.e., an abort) in
servers that both support SSLv2 and enable export cipher suites by sending
a specially crafted SSLv2 CLIENT-MASTER-KEY message.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0
and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was discovered by Sean Burford (Google) and Emilia Käsper
(OpenSSL development team) in March 2015 and the fix was developed by
Emilia Käsper.

Empty CKE with client auth and DHE (CVE-2015-1787)
==================================================

Severity: Moderate

If client auth is used then a server can seg fault in the event of a DHE
ciphersuite being selected and a zero length ClientKeyExchange message being
sent by the client. This could be exploited in a DoS attack.

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 users should upgrade to 1.0.2a.

This issue was discovered and the fix was developed by Matt Caswell of the
OpenSSL development team.

Handshake with unseeded PRNG (CVE-2015-0285)
============================================

Severity: Low

Under certain conditions an OpenSSL 1.0.2 client can complete a handshake with
an unseeded PRNG. The conditions are:
- The client is on a platform where the PRNG has not been seeded automatically,
and the user has not seeded manually
- A protocol specific client method version has been used (i.e. not
SSL_client_methodv23)
- A ciphersuite is used that does not require additional random data from the
PRNG beyond the initial ClientHello client random (e.g. PSK-RC4-SHA).

If the handshake succeeds then the client random that has been used will have
been generated from a PRNG with insufficient entropy and therefore the output
may be predictable.

For example using the following command with an unseeded openssl will succeed on
an unpatched platform:

openssl s_client -psk 1a2b3c4d -tls1_2 -cipher PSK-RC4-SHA

This issue affects OpenSSL version: 1.0.2

OpenSSL 1.0.2 users should upgrade to 1.0.2a.

This issue was discovered and the fix was developed by Matt Caswell of the
OpenSSL development team.

Use After Free following d2i_ECPrivatekey error (CVE-2015-0209)
===============================================================

Severity: Low

A malformed EC private key file consumed via the d2i_ECPrivateKey function could
cause a use after free condition. This, in turn, could cause a double
free in several private key parsing functions (such as d2i_PrivateKey
or EVP_PKCS82PKEY) and could lead to a DoS attack or memory corruption
for applications that receive EC private keys from untrusted
sources. This scenario is considered rare.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0 and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was discovered by the BoringSSL project and fixed in their commit
517073cd4b. The OpenSSL fix was developed by Matt Caswell of the OpenSSL
development team.

X509_to_X509_REQ NULL pointer deref (CVE-2015-0288)
===================================================

Severity: Low

The function X509_to_X509_REQ will crash with a NULL pointer dereference if
the certificate key is invalid. This function is rarely used in practice.

This issue affects all current OpenSSL versions: 1.0.2, 1.0.1, 1.0.0
and 0.9.8.

OpenSSL 1.0.2 users should upgrade to 1.0.2a
OpenSSL 1.0.1 users should upgrade to 1.0.1m.
OpenSSL 1.0.0 users should upgrade to 1.0.0r.
OpenSSL 0.9.8 users should upgrade to 0.9.8zf.

This issue was discovered by Brian Carpenter and a fix developed by Stephen
Henson of the OpenSSL development team.

Note
====

As per our previous announcements and our Release Strategy
(https://www.openssl.org/about/releasestrat.html), support for OpenSSL versions
1.0.0 and 0.9.8 will cease on 31st December 2015. No security updates for these
releases will be provided after that date. Users of these releases are advised
to upgrade.

References
==========

URL for this Security Advisory:
https://www.openssl.org/news/secadv_20150319.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/about/secpolicy.html

2 thoughts on “March 19th OpenSSL Vulnerabilities Overview

  1. > The fork was originally started after the Heartbleed bug

    This is wrong. OpenBSD developers even say it themselves.

    • Well it wasn't HeartBleed, but trying to fix Heartbleed and the other bugs popping up at the time. Per Ted Unangst:

      Heartbleed is the obvious place to start, but at the time it was just another in a serious of annual catastrophic OpenSSL bugs. The ease and speed with which 20 different exploits showed up on github was a new twist, but the “drop everything, set your hair on fire, patch OpenSSL” mania was otherwise about par for the course. There was also the wrinkle that the bug was in a default activated feature used by zero people that one couldn’t disable without recompiling the whole library. That probably would have lead to a tightened review process for any further OpenSSL updates in order to avoid more poison slipping in, but not a fork…

      HeartBleed wasn't the direct cause, but it is the historical event that trigger a cascade of events triggering. their journey down fork lane.

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