NetBSD Security Advisory 2012-002: OpenSSL Invalid TLS/DTLS record attack

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

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

                NetBSD Security Advisory 2012-002
                =================================

Topic:          OpenSSL Invalid TLS/DTLS record attack


Version:        NetBSD-current:         source prior to May 12th, 2012
                NetBSD 6.0 Beta:        affected
                NetBSD 5.0.*:           affected
                NetBSD 5.0:             affected
                NetBSD 5.1:             affected
                NetBSD 4.0.*:           affected
                NetBSD 4.0:             affected

Severity:       remote DoS

Fixed:          NetBSD-current:         May 11th, 2012
                NetBSD 6.0 Beta:        May 22nd, 2012
                NetBSD-5-0 branch:      May 22nd, 2012
                NetBSD-5-1 branch:      May 22nd, 2012
                NetBSD-5 branch:        May 22nd, 2012
                NetBSD-4-0 branch:      May 22nd, 2012
                NetBSD-4 branch:        May 22nd, 2012

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
========

Citing http://www.openssl.org/news/secadv_20120510.txt:

A flaw in the OpenSSL handling of CBC mode ciphersuites in TLS 1.1, 1.2 and
DTLS can be exploited in a denial of service attack on both clients and
servers.

DTLS applications are affected in all versions of OpenSSL. TLS is only
affected in OpenSSL 1.0.1 and later.

TLS is thus affected in NetBSD-6 and -current.

This vulnerability has been assigned CVE-2012-2333


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

When receiving TLS or DTLS packets, OpenSSL first subtracts the
number of padding bytes from the record size. Next, it subtracts
the size of a data structure used to initialize CBC encryption modes;
in the vulnerable version without checking the remaining size of
the record, allowing to result in negative values that re-map into
rather large record size and consequently buffer over-read and
segfault.


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

Patch, recompile, and reinstall the library.

src/crypto/external/bsd/openssl/dist/ssl/d1_enc.c 
CVS branch      Rev.
HEAD            1.2
netbsd-6        1.1.1.3.4.1

src/crypto/dist/openssl/ssl/d1_enc.c
CVS branch      Rev.
netbsd-5        1.1.1.3.4.1
netbsd-5-0      1.1.1.3.8.1
netbsd-5-1      1.1.1.3.12.1
netbsd-4        1.1.1.2.4.1
netbsd-4-0      1.1.1.2.14.1

src/crypto/external/bsd/openssl/dist/ssl/t1_enc.c
CVS branch      Rev.
HEAD            1.4
netbsd-6        1.3.4.1


Thanks To
=========

Thanks to Codenomicon for discovering and Stephen Henson of the
OpenSSL core team for fixing this issue.


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

        2012-06-06      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-SA2012-002.txt.asc

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


Copyright 2012, The NetBSD Foundation, Inc.  All Rights Reserved.
Redistribution permitted only in full, unmodified form.

$NetBSD: NetBSD-SA2012-002.txt,v 1.2 2012/06/06 19:46:15 tonnerre Exp $

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.12 (GNU/Linux)

iQIcBAEBAgAGBQJPz7P/AAoJEAZJc6xMSnBuqSoP/22Y7NVE7UUMqExQS3uLL5+g
cpM7TqagKTj2asjTravEHdmW8q6Exli4rYNGBoU3D6tWC1w/Zcoo6LHqI1IXjjTC
qRsMdjxkPsn64MLKlc48j+ofXeM63Wir7RzqhwrBaf0Lqj4LB/PTK40/B+VTGpCo
somraDXR1XvrmJKc2W6GcC92906r1kM9FJ0OOk6btO2PZxk4eOP3moZ3WRvYyOZz
0W4RJOBWN0w93qNY5mRi106RRjNMFFJHd6p7Fq5SsZJ59/VBXn76NQt4umJVlsKK
ArY06lPkNsxCu6Oak+qWM2efHARez772TXaRrR+/SHcnLuETAWRuQpNYGobU5HrJ
bgYqmlzxIEThGOp2fenh1a4GTZmuMBbh6kOFXsJdOsJPST8Rbmq5XYZRSbBwX5E/
Jw7JjM8h45dH1ORWWSqH2KVwEOlztcmwv04XroUX7kr0+upPudCw50k0EF90Bope
n3qzA4LDnAY8DiSS1b8SVynt1A0B03bvf9oZ1d85duijBSuNPUD3MDUsdUdt41lq
ilz6k2V6OqwDCo83KsZX5FX8x2rCxohexPO3UwgexuDm3oUlWKs2Yw9Q+0gFx0F4
vaAkfS9QP+5CDiJYmxWr5lyyFg+cIbCIryhvCFvdNyp0IfqhD7+EjGJHJZm3YfqQ
V2BSsFuRc+b2/T7yQKCI
=8ttV
-----END PGP SIGNATURE-----