[NetBSD] Schwachstelle in OpenSSL - 2001-013

win-sec-ssc at cert.dfn.de win-sec-ssc at cert.dfn.de
Don Aug 23 16:55:45 CEST 2001


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Sehr geehrte Kolleginnen und Kollegen,

soeben erreichte uns nachfolgende Warnung des NetBSD Security Officers
ueber Sicherheitsprobleme in "OPenSSL". Wir geben diese Informationen
unveraendert an Sie weiter.

Es existiert ein Fehler bei der Erzeugung von Zufallszahlen. Ein
Angreifer, ist bei Anwendungen die kleine Zufallszahlen (jeweils 1
Byte) vom "OpenSSL" Zufallsgenerators anfordern in der Lage,
nachfolgende Zufallszahlen vorherzusagen. Es ist aber unwahrscheinl-
ich, dass diese Schwachstelle ausgenutzt werden kann, weil die meisten
Anwendungen groessere Zufallszahlen anfordern.

Betroffen sind NetBSD-Systeme mit "OpenSSL" bis ausschliesslich
Version 0.9.6b bzw. 0.9.6nb.

(c) der deutschen Zusammenfassung bei DFN-CERT GmbH; die Verbreitung,
auch auszugsweise, ist nur unter Hinweis auf den Urheber, DFN-CERT GmbH,
und nur zu nicht kommerziellen Zwecken gestattet.

Mit freundlichen Gruessen,
	Marco Thorbruegge, DFN-CERT
- -- 
Marco Thorbruegge        |              mailto:thorbruegge at cert.dfn.de
DFN-CERT GmbH            |          http://www.cert.dfn.de/team/matho/
Oberstrasse 14b          |                    Phone: +49(40)808077-555
D-20144 Hamburg          |                      FAX: +49(40)808077-556
Germany                  | PGP-Key: finger thorbruegge at ftp.cert.dfn.de


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                 NetBSD Security Advisory 2001-013
                 =================================

Topic:		OpenSSL PRNG weakness (up to 0.9.6a)

Version:	NetBSD-current:	source prior to July 10, 2001
		NetBSD 1.5.1:	affected
		NetBSD 1.5:	affected
		pkgsrc:		openssl packages prior to 0.9.6b or 0.9.6nb1

Severity:	attacker can predict sequence of future PRNG outputs

Fixed:		NetBSD-current:		July 10, 2001
		NetBSD-1.5 branch:	July 29, 2001 (1.5.2 includes the fix)
		pkgsrc:			openssl-0.9.6b or openssl-0.9.6nb1

Abstract
========

The OpenSSL libcrypto includes a PRNG (pseudo random number generator)
implementation.  The logic used for PRNG was not strong enough,
and allows attackers to guess the internal state of the PRNG.
Therefore, attackers can predict future PRNG output.


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

http://www.openssl.org/news/secadv_prng.txt


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

The problem can be remedied by replacing the libcrypto library,
and recompiling all statically-linked binaries on the system that
use this library.

The following instructions describe how to upgrade your openssl
libraries by updating your source tree and rebuilding and installing
a new version of telnetd(8).


* All NetBSD releases using openssl from pkgsrc:

	If you are using openssl from pkgsrc, upgrade it to either of
	the following packages:
		openssl-0.9.6b or higher
		openssl-0.9.6nb1 (0.9.6 + specific fix for the issue)

	Also, make sure that you upgrade any statically-linked binaries
	in packages and local applications that have been linked with
	libcrypto.


* NetBSD-current:

	Systems running NetBSD-current dated from before 2001-07-10
	should be upgraded to NetBSD-current dated 2001-07-11 or later.

	The following directories need to be updated from the
	netbsd-current CVS branch (aka HEAD):
		src/crypto/dist/openssl
		src/lib/libcrypto

	To update from CVS, re-build, and re-install the openssl
	libraries:
		# cd src
		# cvs update -d -P crypto/dist/openssl lib/libcrypto
		# cd lib/libcrypto
		# make cleandir dependall
		# make install

	You also need to upgrade any statically-linked binaries
	that use libcrypto.  Whilst there are no statically-linked
	binaries in the default NetBSD installation that use
	libcrypto, it would be a good idea to run a full build
	(i.e. "make build").


* NetBSD 1.5, 1.5.1:

	Systems running NetBSD 1.5 or 1.5.1 sources dated from
	before 2001-07-29 should be upgraded from NetBSD 1.5.x
	sources dated 2001-07-30 or later.

	NetBSD 1.5.2 is not vulnerable.

	The following source needs to be updated to version 1.2
	or later from the netbsd-1-5 CVS branch:
		crypto/dist/openssl/crypto/rand/md_rand.c

	To update from CVS, re-build, and re-install the openssl
	libraries:
		# cd src
		# cvs update -d -P crypto/dist/openssl/crypto/rand
		# cd lib/libcrypto
		# make cleandir dependall
		# make install


        Alternatively, apply the following patch (with potential offset
        differences):
                ftp://ftp.netbsd.org/pub/NetBSD/security/patches/SA2001-013-openssl-1.5.patch

	To patch, re-build and re-install the openssl libraries:
		# cd src/crypto/dist/openssl/crypto/rand
		# patch < /path/to/SA2001-013-openssl-1.5.patch
		# cd ../../../../../lib/libcrypto
		# make cleandir dependall
		# make install


	You also need to upgrade any statically-linked binaries
	that use libcrypto.  Whilst there are no statically-linked
	binaries in the default NetBSD installation that use
	libcrypto, it would be a good idea to run a full build
	(i.e. "make build").


Thanks To
=========

Jun-ichiro Hagino for the fix to -current and 1.5

Markku-Juhani O. Saarinen for discovering the problem
in the PRNG and reporting it to the OpenSSL project.


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

	2001-08-23	Initial release


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

An up-to-date PGP signed copy of this release will be maintained at
  ftp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2001-013.txt.asc

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


Copyright 2001, The NetBSD Foundation, Inc.  All Rights Reserved.

$NetBSD: NetBSD-SA2001-013.txt,v 1.13 2001/08/23 02:03:23 lukem Exp $

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