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[Mandrake] Schwachstelle bei GPG El-Gamal Schluesseln - MDKSA-2003:109
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Liebe Kolleginnen und Kollegen,
soeben erreichte uns nachfolgendes Advisory von Mandrakesoft Security
ueber Sicherheitsprobleme bei GnuPG. Wir geben diese Informationen
unveraendert an Sie weiter.
Wir gaben bereits ein Advisory zu dem Thema weiter. Zur Erinnerung:
El-Gamal Schluessel, die mit GnuPG erzeugt und zum Signieren benutzt
wurden, sind kompromittierbar, d.h. der Secret Key kann bestimmt
werden. Damit sind Nachrichteninhalte entschluesselbar (falls mit dem
Schluessel auch verschluesselt wurde) bzw. koennen Fremde gueltige
Signaturen mit diesem Schluessel erzeugen.
Es wird empfohlen, keine El-Gamal Sign+Encrypt Schluessel mehr zu
erzeugen und alle bereits erzeugten El-Gamal Sign+Encrypt Schluessel
und Subkeys (Typ 20) zu widerrufen (d.h. Revocation Certificate fuer
diese Schluessel zu veroeffentlichen).
Bitte beachten Sie, dass die gemaess den Standard-Einstellungen
generierten Schluessel, die eine Kombination der Verfahren DSA und
ElGamal verwenden, nicht betroffen sind. Weiterhin sind ebenso RSA
Schluessel sowie El-Gamal Subkeys, die nur zum Verschluesseln benutzt
werden (Typ 16), nicht betroffen.
Betroffen ist Mandrake Linux 9.0 bis 9.2, sowie der Corporate Server
2.1 und die Multi Network Firewall 8.2. Der Hersteller stellt Patches
zur Behebung der Schwachstelle bereit.
(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,
Andreas Bunten, DFN-CERT
- --
Andreas Bunten | mailto:bunten@xxxxxxxxxxx
DFN-CERT GmbH | http://www.cert.dfn.de/team/bunten/
Heidenkampsweg 41 | Phone: +49(40)808077-555
D-20097 Hamburg | FAX: +49(40)808077-556
Germany | PGP-Key: finger bunten@xxxxxxxxxxxxxxx
PGP-Key fingerprint = 25 E9 A6 DD 15 6C 09 70 9D 05 10 2B C7 AB C2 31
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Hash: SHA1
_______________________________________________________________________
Mandrake Linux Security Update Advisory
_______________________________________________________________________
Package name: gnupg
Advisory ID: MDKSA-2003:109
Date: November 28th, 2003
Affected versions: 9.0, 9.1, 9.2, Corporate Server 2.1,
Multi Network Firewall 8.2
______________________________________________________________________
Problem Description:
A severe vulnerability was discovered in GnuPG by Phong Nguyen
relating to ElGamal sign+encrypt keys. From Werner Koch's email
message:
"Phong Nguyen identified a severe bug in the way GnuPG creates and uses
ElGamal keys for signing. This is a significant security failure
which can lead to a compromise of almost all ElGamal keys used for
signing. Note that this is a real world vulnerability which will
reveal your private key within a few seconds.
Please *take immediate action and revoke your ElGamal signing keys*.
Furthermore you should take whatever measures necessary to limit the
damage done for signed or encrypted documents using that key."
And also:
"Note that the standard keys as generated by GnuPG (DSA and ElGamal
encryption) as well as RSA keys are NOT vulnerable. Note also that
ElGamal signing keys cannot be generated without the use of a special
flag to enable hidden options and even then overriding a warning
message about this key type. See below for details on how to identify
vulnerable keys."
MandrakeSoft urges any users who use the ElGamal sign+encrypt keys to
immediately revoke these keys and discontinue use of them. Updated
packages are provided that remove the ability to create these keys and
to create signatures using these keys (thanks to David Shaw for
writing the patch).
_______________________________________________________________________
References:
http://lists.gnupg.org/pipermail/gnupg-announce/2003q4/000276.html
______________________________________________________________________
Updated Packages:
Corporate Server 2.1:
d134c826e4fae506ccde3be7686888bc corporate/2.1/RPMS/gnupg-1.0.7-3.2.C21mdk.i586.rpm
9294c6b3587a3a177b1d7ac57c1a0db2 corporate/2.1/SRPMS/gnupg-1.0.7-3.2.C21mdk.src.rpm
Corporate Server 2.1/x86_64:
7c4be5a2e952dd10c10f9242b91b51de x86_64/corporate/2.1/RPMS/gnupg-1.0.7-3.2.C21mdk.x86_64.rpm
9294c6b3587a3a177b1d7ac57c1a0db2 x86_64/corporate/2.1/SRPMS/gnupg-1.0.7-3.2.C21mdk.src.rpm
Mandrake Linux 9.0:
f4f876cd0988362fba3718450727fd95 9.0/RPMS/gnupg-1.0.7-3.2.90mdk.i586.rpm
a459cb6e80e56562eac4a40a2ece3777 9.0/SRPMS/gnupg-1.0.7-3.2.90mdk.src.rpm
Mandrake Linux 9.1:
cdec75d7675fdb36874e61795800f582 9.1/RPMS/gnupg-1.2.2-1.2.91mdk.i586.rpm
08bba4f56d5d5eb581be7170e058133a 9.1/SRPMS/gnupg-1.2.2-1.2.91mdk.src.rpm
Mandrake Linux 9.1/PPC:
4c41071186f40d9895a1032ced8d0601 ppc/9.1/RPMS/gnupg-1.2.2-1.2.91mdk.ppc.rpm
08bba4f56d5d5eb581be7170e058133a ppc/9.1/SRPMS/gnupg-1.2.2-1.2.91mdk.src.rpm
Mandrake Linux 9.2:
03d66699b92149590b078298063a1744 9.2/RPMS/gnupg-1.2.3-3.1.92mdk.i586.rpm
0f5d1244d156a0b229c0d27e07c67b35 9.2/SRPMS/gnupg-1.2.3-3.1.92mdk.src.rpm
Multi Network Firewall 8.2:
b59a3c9a6c27c8d0c52e7a83d1ca3c75 mnf8.2/RPMS/gnupg-1.0.7-3.2.M82mdk.i586.rpm
d4dbfe3968a94705f7a7e175e00d03c9 mnf8.2/SRPMS/gnupg-1.0.7-3.2.M82mdk.src.rpm
_______________________________________________________________________
To upgrade automatically use MandrakeUpdate or urpmi. The verification
of md5 checksums and GPG signatures is performed automatically for you.
A list of FTP mirrors can be obtained from:
http://www.mandrakesecure.net/en/ftp.php
All packages are signed by MandrakeSoft for security. You can obtain
the GPG public key of the Mandrake Linux Security Team by executing:
gpg --recv-keys --keyserver www.mandrakesecure.net 0x22458A98
Please be aware that sometimes it takes the mirrors a few hours to
update.
You can view other update advisories for Mandrake Linux at:
http://www.mandrakesecure.net/en/advisories/
MandrakeSoft has several security-related mailing list services that
anyone can subscribe to. Information on these lists can be obtained by
visiting:
http://www.mandrakesecure.net/en/mlist.php
If you want to report vulnerabilities, please contact
security_linux-mandrake.com
Type Bits/KeyID Date User ID
pub 1024D/22458A98 2000-07-10 Linux Mandrake Security Team
<security linux-mandrake.com>
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