__________________________________________________________ The U.S. Department of Energy Computer Incident Advisory Capability ___ __ __ _ ___ / | /_\ / \___ __|__ / \ \___ __________________________________________________________ INFORMATION BULLETIN Red Hat GnuPG Packages ElGamal Keys Vulnerability [Red Hat Security Advisories: RHSA-2003:390-18 and RHSA-2003:395-13] December 11, 2003 20:00 GMT Number O-037 [REVISED 18 Dec 2003] [REVISED 27 Jan 2004] [REVISED 27 Feb 2004] ______________________________________________________________________________ PROBLEM: ElGamal keys are used for both signing and encrypting functions. A vulnerability has been identified in the way GnuPG packages create and use these keys. PLATFORM: Red Hat Linux 7.1, 7.2, 7.3, 8.0 and 9 Red Hat Enterprise Linux AS, ES, and WS (v2.1 and v3) Red Hat Linux Advanced Workstation 2.1 for the Itanium Processor SGI ProPack v2.4 Debian GNU/Linux 3.0 (woody) DAMAGE: In GnuPG packages, unsafe keys can be generated if someone overides the default settings when generating them. This could allow an attacker to have unauthorized recovery and use of users' private keys. SOLUTION: Red Hat suggests revoking ElGamal keys or to install their updated GnuPG packages which will disable functions that either generate or use ElGamal keys. ______________________________________________________________________________ VULNERABILITY The risk is HIGH. ElGamal is a widely distributed security ASSESSMENT: algorithm being used in Red Hat's GnuPG packages. An attacker could get access to a user's private key and operate under their identity. ______________________________________________________________________________ LINKS: CIAC BULLETIN: http://www.ciac.org/ciac/bulletins/o-037.shtml ORIGINAL BULLETINS: https://rhn.redhat.com/errata/RHSA-2003-390.html https://rhn.redhat.com/errata/RHSA-2003-395.html ADDITIONAL SGI security update #7 INFORMATION: ftp://patches.sgi.com/support/free/security/advisories/ 20031203-01-U.asc Debian Security Advisory DSA-429-1 http://www.debian.org/security/2004/dsa-429 SGI Security Advisory 20040202-01-U Update #11 ftp://patches.sgi.com/support/free/security/advisories/20040202-01-U.asc CVE/CAN: http://www.cve.mitre.org/cgi-bin/cvename.cgi?name= CAN-2003-0971 ______________________________________________________________________________ REVISION HISTORY: 12/18/03 - added a link to SGI's Security Update #7 announcing the release of their Patch 10039 for this vulnerability. 01/27/04 - adding a link to Debian Security Advisory DSA-429-1 announcing the release of an updated version Debian GNU/Linux 3.0 (woody). 02/27/04 - adding a link to SGI's Security Update #11 announcing the release of their Patch 10044 for this vulnerability. NOTE: RHSA-2003:395-13 gives information on the Red Hat Enterprise Linux product lines. [***** Start Red Hat Security Advisories: RHSA-2003:390-18 *****] Updated gnupg packages disable ElGamal keys Advisory: RHSA-2003:390-18 Last updated on: 2003-12-10 Affected Products: Red Hat Linux 7.1 Red Hat Linux 7.2 Red Hat Linux 7.3 Red Hat Linux 8.0 Red Hat Linux 9 CVEs (cve.mitre.org): CAN-2003-0971 Security Advisory Details: Updated gnupg packages are now available for Red Hat Linux. These updates disable the ability to generate ElGamal keys (used for both signing and encrypting) and disable the ability to use ElGamal public keys for encrypting data. GnuPG is a utility for encrypting data and creating digital signatures. Phong Nguyen identified a severe bug in the way GnuPG creates and uses ElGamal keys, when those keys are used both to sign and encrypt data. This vulnerability can be used to trivially recover the private key. While the default behavior of GnuPG when generating keys does not lead to the creation of unsafe keys, by overriding the default settings an unsafe key could have been created. If you are using ElGamal keys, you should revoke those keys immediately. The packages included in this update do not make ElGamal keys safe to use; they merely include a patch by David Shaw that disables functions that would generate or use ElGamal keys. To determine if your key is affected, run the following command to obtain a list of secret keys that you have on your secret keyring: gpg --list-secret-keys The output of this command includes both the size and type of the keys found, and will look similar to this example: /home/example/.gnupg/secring.gpg ---------------------------------------------------- sec 1024D/01234567 2000-10-17 Example User uid Example User The key length, type, and ID are listed together, separated by a forward slash. In the example output above, the key's type is "D" (DSA, sign and encrypt). Your key is unsafe if and only if the key type is "G" (ElGamal, sign and encrypt). In the above example, the secret key is safe to use, while the secret key in the following example is not: /home/example/.gnupg/secring.gpg ---------------------------------------------------- sec 1024G/01234567 2000-10-17 Example User uid Example User For more details regarding this issue, as well as instructions on how to revoke any keys that are unsafe, refer to the advisory available from the GnuPG web site: http://www.gnupg.org/ Updated packages: Red Hat Linux 7.1 -------------------------------------------------------------------------------- SRPMS: gnupg-1.0.7-12.src.rpm [ via FTP ] [ via HTTP ] 4d62554490e85b7cc1f0cfef6518a979 i386: gnupg-1.0.7-12.i386.rpm [ via FTP ] [ via HTTP ] 0591a2079aff5e7979b0225b568bceaa Red Hat Linux 7.2 -------------------------------------------------------------------------------- SRPMS: gnupg-1.0.7-13.src.rpm [ via FTP ] [ via HTTP ] b619c30c293094d7dcd18487d8e62a43 i386: gnupg-1.0.7-13.i386.rpm [ via FTP ] [ via HTTP ] e7e3e75afd1ccd2267ccc7847c76ebb4 ia64: gnupg-1.0.7-13.ia64.rpm [ via FTP ] [ via HTTP ] 6fb21011ca42ff395b8cfc7dce4c2936 Red Hat Linux 7.3 -------------------------------------------------------------------------------- SRPMS: gnupg-1.0.7-13.src.rpm [ via FTP ] [ via HTTP ] b619c30c293094d7dcd18487d8e62a43 i386: gnupg-1.0.7-13.i386.rpm [ via FTP ] [ via HTTP ] e7e3e75afd1ccd2267ccc7847c76ebb4 Red Hat Linux 8.0 -------------------------------------------------------------------------------- SRPMS: gnupg-1.0.7-14.src.rpm [ via FTP ] [ via HTTP ] bc375882f13e5c10eb29eb3615de911d i386: gnupg-1.0.7-14.i386.rpm [ via FTP ] [ via HTTP ] a3de0844778cd994258f121330ff6d62 Red Hat Linux 9 -------------------------------------------------------------------------------- SRPMS: gnupg-1.2.1-9.src.rpm [ via FTP ] [ via HTTP ] e1f31f4a07ebb5b4040f8f6ca3816cc4 i386: gnupg-1.2.1-9.i386.rpm [ via FTP ] [ via HTTP ] 604a2fb5b809ec99280871f46507f4a1 Solution Before applying this update, make sure all previously released errata relevant to your system have been applied. To update all RPMs for your particular architecture, run: rpm -Fvh [filenames] where [filenames] is a list of the RPMs you wish to upgrade. Only those RPMs which are currently installed will be updated. Those RPMs which are not installed but included in the list will not be updated. Note that you can also use wildcards (*.rpm) if your current directory *only* contains the desired RPMs. Please note that this update is also available via Red Hat Network. Many people find this an easier way to apply updates. To use Red Hat Network, launch the Red Hat Update Agent with the following command: up2date This will start an interactive process that will result in the appropriate RPMs being upgraded on your system. If up2date fails to connect to Red Hat Network due to SSL Certificate Errors, you need to install a version of the up2date client with an updated certificate. The latest version of up2date is available from the Red Hat FTP site and may also be downloaded directly from the RHN website: https://rhn.redhat.com/help/latest-up2date.pxt References: http://cve.mitre.org/cgi-bin/cvename.cgi?name=CAN-2003-0971 http://lists.gnupg.org/pipermail/gnupg-announce/2003q4/000276.html http://lists.gnupg.org/pipermail/gnupg-users/2003-November/020779.html http://lists.gnupg.org/pipermail/gnupg-announce/2003q4/000277.html Keywords: elgamal, encrypt, gnupg, sign -------------------------------------------------------------------------------- The listed packages are GPG signed by Red Hat, Inc. for security. Our key is available at: http://www.redhat.com/solutions/security/news/publickey/#key You can verify each package and see who signed it with the following command: rpm --checksig -v filename If you only wish to verify that each package has not been corrupted or tampered with, examine only the md5sum with the following command: md5sum filename The Red Hat security contact is security@redhat.com. More contact details at http://www.redhat.com/solutions/security/news/contact.html Copyright © 2002 Red Hat, Inc. All rights reserved. Search by Google Careers at Red Hat : Legal statement : Privacy statement : Your Account : Credits : Contact Red Hat [***** End Red Hat Security Advisories: RHSA-2003:390-18 *****] _______________________________________________________________________________ CIAC wishes to acknowledge the contributions of Red Hat, Inc. for the information contained in this bulletin. _______________________________________________________________________________ CIAC, the Computer Incident Advisory Capability, is the computer security incident response team for the U.S. Department of Energy (DOE) and the emergency backup response team for the National Institutes of Health (NIH). CIAC is located at the Lawrence Livermore National Laboratory in Livermore, California. CIAC is also a founding member of FIRST, the Forum of Incident Response and Security Teams, a global organization established to foster cooperation and coordination among computer security teams worldwide. CIAC services are available to DOE, DOE contractors, and the NIH. CIAC can be contacted at: Voice: +1 925-422-8193 (7x24) FAX: +1 925-423-8002 STU-III: +1 925-423-2604 E-mail: ciac@ciac.org Previous CIAC notices, anti-virus software, and other information are available from the CIAC Computer Security Archive. World Wide Web: http://www.ciac.org/ Anonymous FTP: ftp.ciac.org PLEASE NOTE: Many users outside of the DOE, ESnet, and NIH computing communities receive CIAC bulletins. If you are not part of these communities, please contact your agency's response team to report incidents. Your agency's team will coordinate with CIAC. The Forum of Incident Response and Security Teams (FIRST) is a world-wide organization. A list of FIRST member organizations and their constituencies can be obtained via WWW at http://www.first.org/. This document was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor the University of California nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial products, process, or service by trade name, trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement, recommendation or favoring by the United States Government or the University of California. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or the University of California, and shall not be used for advertising or product endorsement purposes. 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