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Home » Security Advisories» NetBSD » NetBSD 2003-005: timing attack in OpenSSL

NetBSD 2003-005: timing attack in OpenSSL

The attack allows remote recovery of private keys, from a host with low-latency access to the server - such as the local host, or a host on the LAN.

  • Vendor: NetBSD
  • Vendor ID: 2003-005
  • Date: March 26, 2003


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NetBSD Security Advisory 2003-005
=================================

Topic: RSA timing attack in OpenSSL code

Version: NetBSD-current: source prior to March 19, 2003
NetBSD-1.6: affected (NetBSD-1.6.1 will include the fix)
NetBSD-1.5.3: affected
NetBSD-1.5.2: affected
NetBSD-1.5.1: affected
NetBSD-1.5: affected
NetBSD-1.4*: not affected
pkgsrc: prior to openssl-0.9.6gnb2

Severity: Cryptographic keys can be compromised remotely.

Fixed: NetBSD-current: March 19, 2003
NetBSD-1.6 branch: March 21, 2003 (1.6.1 will include the fix)
NetBSD-1.5 branch: March 21, 2003
pkgsrc: openssl-0.9.6gnb2


Abstract
========

A timing attack has been discovered, which can be used against OpenSSL.
The attack allows remote recovery of private keys, from a host with
low-latency access to the server - such as the local host, or a host on
the LAN.

Research shows that about a million queries are sufficient to extract a
1024-bit RSA key. Any program that uses OpenSSL's RSA logic could be
affected.

NOTE: Two OpenSSL advisories have appeared within 2 days of each other.
while the patches affect libcrypto in this SA, and libssl in
2003-007, please be aware that there are two separate issues
with separate sets of patches.


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

http://crypto.stanford.edu/~dabo/abstracts/ssl-timing.html


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

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

Be sure to restart running instances of programs that use the libcrypto
library after upgrading.

If you have any statically-linked binaries that linked against a
vulnerable libcrypto, you need to recompile them.


* NetBSD-current:

Systems running NetBSD-current dated from before 2003-03-19
should be upgraded to NetBSD-current dated 2003-03-19 or later.

The following file needs to be updated from the
netbsd-current CVS branch (aka HEAD):
crypto/dist/openssl/crypto/rsa

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


* NetBSD 1.6:

The binary distribution of NetBSD 1.6 is vulnerable.

Systems running NetBSD-1-6 from sources dated before 2002-03-21
should be upgraded to NetBSD-1-6 branch sources dated 2003-03-21
or later.

The following files need to be updated from the
netbsd-1-6 CVS branch:
crypto/dist/openssl/crypto/rsa

To update from CVS, re-build, and re-install libcrypto:
# cd src
# cvs update -d -P -r netbsd-1-6 crypto/dist/openssl/crypto/rsa
# cd lib/libcrypto
# make USETOOLS=no cleandir dependall
# make USETOOLS=no install


* NetBSD 1.5, 1.5.1, 1.5.2, 1.5.3:

The binary distribution of NetBSD 1.5.3 is vulnerable.

Systems running NetBSD-1.5.x dated from before 2003-xx-xx
should be upgraded to NetBSD-1.5 branch dated 2003-xx-xx or later.

The following file needs to be updated from the
netbsd-1-5 CVS branch:
crypto/dist/openssl/crypto/rsa

To update from CVS, re-build, and re-install libcrypto:
# cd src
# cvs update -d -P -r netbsd-1-5 crypto/dist/openssl/ssl/s3_pkt.c
# cd lib/libcrypto
# make cleandir dependall
# make install


* NetBSD 1.4, 1.4.1, 1.4.2, 1.4.3:

OpenSSL was not included in the base system in NetBSD-1.4.*
Follow the directions for pkgsrc if you have installed it from
pkgsrc.


* pkgsrc:

openssl (pkgsrc/security/openssl) prior to 0.9.6gnb2 are
vulnerable. Upgrade to openssl-0.9.6gnb2 or later; pkgsrc
currently contains openssl-0.9.6gnb1 at time of this writing.

Packages which require openssl can be found by running 'pkg_info
openssl'. Depending on the method you choose to update pkgsrc
packages, a rebuild of the packages on that list may be
performed for you by the package system. If you update using the
experimental 'make replace' target, you will need to manually
update any packages which build static binaries with libcrypto.a.

If you have statically linked binaries in pkgsrc, they have to be
rebuilt. Statically linked binaries can be identified by the
following command (note: be sure to include the directory you install
pkgsrc binaries to, if you've changed LOCALBASE from the default of
/usr/pkg)

file /usr/pkg/{bin,sbin,libexec}/* | grep static


Thanks To
=========

Bugtraq and the OpenSSL team.


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

2003-03-26 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-SA2003-005.txt.asc

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


Copyright 2003, The NetBSD Foundation, Inc. All Rights Reserved.

$NetBSD: NetBSD-SA2003-005.txt,v 1.7 2003/03/26 06:14:37 david Exp $

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