NetBSD Security Advisory 2010-002: OpenSSL TLS renegotiation man in the middle vulnerability

[NetBSD Security Officer <security-officer%NetBSD.org@localhost>]

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                 NetBSD Security Advisory 2010-002
                 =================================

Topic:          OpenSSL TLS renegotiation man in the middle vulnerability


Version:        NetBSD-current:         affected prior to 2009-12-04
                NetBSD 5.0:             affected
                NetBSD 4.0.*:           affected
                NetBSD 4.0:             affected
                pkgsrc:                 openssl package prior to x.y.z


Severity:       Information disclosure


Fixed:          NetBSD-current:         Dec 03, 2009
                NetBSD-5-0 branch:      Jan 12, 2010
                NetBSD-5 branch:        Jan 12, 2010
                NetBSD-4-0 branch:      Jan 12, 2010
                NetBSD-4 branch:        Jan 12, 2010
                pkgsrc 2009Q4:          openssl-0.9.8l corrects this issue

Please note that NetBSD releases prior to 4.0 are no longer supported.
It is recommended that all users upgrade to a supported release.



Abstract
========

An error in the OpenSSL TLS session renegotiation allows a remote
attacker to intercept communication and conduct a Man-in-the-Middle
attack on TLS sessions.

This vulnerability has been assigned CVE-2009-3555 and CERT
Vulnerability Note VU#120541.


Technical Details
=================

A design problem exists in the renegotiation feature for TLS sessions as
implemented by the version of OpenSSL shipped with NetBSD.  As session
renegotiation handshakes are not properly associated with an existing
connection, an unauthenticated attacker can initiate a renegotiation in
order to allow a man-in-the-middle attack, which may allow the attacker
to inject plaintext into the communication.


Solutions and Workarounds
=========================

The solution to this problem is to disable TLS session renegotiation for
now by applying the provided patches or updating NetBSD to a version
including the fix.

The following instructions describe how to upgrade your OpenSSL
binaries by updating your source tree and rebuilding and installing
a new version of OpenSSL.

* NetBSD-current:

        Systems running NetBSD-current dated from before 2009-12-04
        should be upgraded to NetBSD-current dated 2009-12-04 or later.

        The following files/directories need to be updated from the
        netbsd-current CVS branch (aka HEAD):
                crypto/external/bsd/openssl/dist/ssl/s3_lib.c
                crypto/external/bsd/openssl/dist/ssl/s3_pkt.c
                crypto/external/bsd/openssl/dist/ssl/s3_srvr.c
                crypto/external/bsd/openssl/dist/ssl/ssl_locl.h

        To update from CVS, re-build, and re-install OpenSSL:
                # cd src
                # cvs update -d -P crypto/external/bsd/openssl/dist/ssl
                # cd crypto/external/bsd/openssl/lib/libssl
                # make USETOOLS=no cleandir dependall
                # make USETOOLS=no install

* NetBSD 5.*:

        Systems running NetBSD 5.* sources dated from before
        2010-01-12 09:30 UTC should be upgraded from NetBSD 5.* sources
        dated 2010-01-12 09:30 UTC or later.

        The following files/directories need to be updated from the
        netbsd-5 or netbsd-5-0 branches:
                crypto/dist/openssl/ssl/s3_lib.c
                crypto/dist/openssl/ssl/s3_pkt.c
                crypto/dist/openssl/ssl/s3_srvr.c
                crypto/dist/openssl/ssl/ssl_locl.h

        To update from CVS, re-build, and re-install OpenSSL:

                # cd src
                # cvs update -r <branch_name> -d -P crypto/dist/openssl/ssl
                # cd lib/libssl
                # make USETOOLS=no cleandir dependall
                # make USETOOLS=no install

* NetBSD 4.*:

        Systems running NetBSD 4.* sources dated from before
        2010-01-12 09:30 UTC should be upgraded from NetBSD 4.* sources
        dated 2010-01-12 09:30 UTC or later.

        The following files/directories need to be updated from the
        netbsd-4 or netbsd-4-0 branches:
                crypto/dist/openssl/ssl/s3_lib.c
                crypto/dist/openssl/ssl/s3_pkt.c
                crypto/dist/openssl/ssl/s3_srvr.c
                crypto/dist/openssl/ssl/ssl_locl.h

        To update from CVS, re-build, and re-install OpenSSL:

                # cd src
                # cvs update -r <branch_name> -d -P crypto/dist/openssl/ssl
                # cd lib/libssl
                # make USETOOLS=no cleandir dependall
                # make USETOOLS=no install


Thanks To
=========

Marsh Ray, PhoneFactor and Martin Rex for discovering and reporting the issue,
and Christos Zoulas for fixing it.


Revision History
================

        2010-01-12      Initial release


More Information
================

Advisories may be updated as new information becomes available.
The most recent version of this advisory (PGP signed) can be found at 
  http://ftp.NetBSD.org/pub/NetBSD/security/advisories/NetBSD-SA2010-002.txt.asc

Information about NetBSD and NetBSD security can be found at
http://www.NetBSD.org/ and http://www.NetBSD.org/Security/.

Copyright 2010, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2010-002.txt,v 1.1 2010/01/12 20:04:35 tonnerre Exp $

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