Stay Secure with the Latest Linux Advisories

security advisoryupdatecritical

SUSE 2006:014 Critical: GPG Remote Code Execution Threat

The GNU Privacy Guard (GPG) allows crafting a message which could The GNU Privacy Guard (GPG) allows crafting a message which could check out correct using "--verify", but would extract a different, check out correct using "--verify", but would extract a different, potentially malicious content when using "-o --batch". The reason for this is that a .gpg or .asc file can contain multiple plain tex [More...]. -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 ______________________________________________________________________________ SUSE Security Announcement Package: gpg Announcement ID: SUSE-SA:2006:014 Date: Fri, 10 Mar 2006 18:00:00 +0000 Affected Products: SUSE LINUX 10.0 SUSE LINUX 9.3 SUSE LINUX 9.2 SUSE LINUX 9.1 SuSE Linux Desktop 1.0 SuSE Linux Enterprise Server 8 SUSE SLES 9 UnitedLinux 1.0 Vulnerability Type: remote code execution Severity (1-10): 9 SUSE Default Package: yes Cross-References: CVE-2006-0049 Content of This Advisory: 1) Security Vulnerability Resolved: gpg signature verification problem Problem Description 2) Solution or Work-Around 3) Special Instructions and Notes 4) Package Location and Checksums 5) Pending Vulnerabilities, Solutions, and Work-Arounds: See SUSE Security Summary Report. 6) Authenticity Verification and Additional Information ______________________________________________________________________________ 1) Problem Description and Brief Discussion The GNU Privacy Guard (GPG) allows crafting a message which could check out correct using "--verify", but would extract a different, potentiallymalicious content when using "-o --batch". The reason for this is that a .gpg or .asc file can contain multiple plain text and signature streams and the handling of these streams was only possible when correctly following the gpg state. The gpg "--verify" option has been changed to be way more strict than before and fail on files with multiple signatures/blocks to mitigate the problem of doing the common --verify checks and -o extraction. This problem could be used by an attacker to remotely execute code by using handcrafted YaST Online Patch files put onto a compromised YOU mirror server and waiting for the user to run YOU. This problem is tracked by the Mitre CVE ID CVE-2006-0049. This is a different issue than the gpg signature checking problem for which we released updates a week ago, tracked by SUSE-SA:2006:013 / CVE-2006-0455. 2) Solution or Work-Around There is no known workaround, please install the update packages. 3) Special Instructions and Notes None. 4) Package Location and Checksums The preferred method for installing security updates is to use the YaST Online Update (YOU) tool. YOU detects which updates are required and automatically performs the necessary steps to verify and install them. Alternatively, download the update packages for your distribution manually and verify their integrity by the methods listed in Section 6 of this announcement. Then install the packages using the command rpm -Fhv to apply the update, replacing with the filename of the downloaded RPM package. x86 Platform: SUSE LINUX 10.0: 17f4db7313fb81477d491cd1de3b4a7c SUSE LINUX 9.3: 781a1f6ee507960c3b7f5ab7b09aae01 SUSE LINUX 9.2: 0ac37c5097314b9d65fe3c00552991ba SUSE LINUX 9.1: 2436ccc119ac1af98928536d2b968a3a Power PC Platform: SUSE LINUX 10.0: 7da97d12baf4aa28e307affa9ccaa2ad x86-64 Platform: SUSE LINUX 10.0: 490728e89c6564ac1e0b679012a89a42 SUSE LINUX 9.3: f258e8971ef2eb171907bbc426e15893 SUSE LINUX 9.2: 3e59895b7bed858997bdbc49aece5644 SUSE LINUX 9.1: 6369420f068f5d935bbc01f4798f2f20 Sources: SUSE LINUX 10.0: a4ee567384c8744bafc59c19ed89669e SUSE LINUX 9.3: 2d392b6698c4a9bb5f2b54aa51b53405 SUSE LINUX 9.2: 1cb53598e1a3c6d31aefc69c2ea18f37 SUSE LINUX 9.1: 91f82734783f307bf64a1728dbcddd79 117ec3bfb057b88b637355db64c74723 Our maintenance customers are notified individually. The packages are offered for installation from the maintenance web: ______________________________________________________________________________ 5) Pending Vulnerabilities, Solutions, and Work-Arounds: See SUSE Security Summary Report. ______________________________________________________________________________ 6) Authenticity Verification and Additional Information - Announcement authenticity verification: SUSE security announcements are published via mailing lists and on Web sites. The authenticity and integrity of a SUSE security announcement is guaranteed by a cryptographic signature in each announcement. All SUSE security announcements are published with a valid signature. To verify the signature of the announcement, save it as text into a file and run the command gpg --verify replacing with the name of the file where you saved the announcement. The output for a valid signature looks like: gpg: Signature made using RSA key ID 3D25D3D9 gpg: Good signature from "SuSE Security Team " where is replaced by the date the document was signed. If the security team's key is not contained in your key ring, you can import it from the first installation CD. To import the key, use the command gpg --import gpg-pubkey-3d25d3d9-36e12d04.asc - Package authenticity verification: SUSE update packages areavailable on many mirror FTP servers all over the world. While this service is considered valuable and important to the free and open source software community, the authenticity and the integrity of a package needs to be verified to ensure that it has not been tampered with. There are two verification methods that can be used independently from each other to prove the authenticity of a downloaded file or RPM package: 1) Using the internal gpg signatures of the rpm package 2) MD5 checksums as provided in this announcement 1) The internal rpm package signatures provide an easy way to verify the authenticity of an RPM package. Use the command rpm -v --checksig to verify the signature of the package, replacing with the filename of the RPM package downloaded. The package is unmodified if it contains a valid signature from This email address is being protected from spambots. You need JavaScript enabled to view it. with the key ID 9C800ACA. This key is automatically imported into the RPM database (on RPMv4-based distributions) and the gpg key ring of 'root' during installation. You can also find it on the first installation CD and at the end of this announcement. 2) If you need an alternative means of verification, use the md5sum command to verify the authenticity of the packages. Execute the command md5sum after you downloaded the file from a SUSE FTP server or its mirrors. Then compare the resulting md5sum with the one that is listed in the SUSE security announcement. Because the announcement containing the checksums is cryptographically signed (by This email address is being protected from spambots. You need JavaScript enabled to view it.), the checksums show proof of the authenticity of the package if the signature of the announcement is valid. Note that the md5 sums published in the SUSE Security Announcements are valid for the respective packages only. Newer versions of these packages cannot be verified. - SUSE runs two security mailing lists to which any interestedparty may subscribe: This email address is being protected from spambots. You need JavaScript enabled to view it. - General Linux and SUSE security discussion. All SUSE security announcements are sent to this list. To subscribe, send an e-mail to . This email address is being protected from spambots. You need JavaScript enabled to view it. - SUSE's announce-only mailing list. Only SUSE's security announcements are sent to this list. To subscribe, send an e-mail to . For general information or the frequently asked questions (FAQ), send mail to or . ==================================================================== SUSE's security contact is or . The public key is listed below. ==================================================================== . SUSE Security Notice for gpg regarding vulnerabilities leading to code execution risks. Apply patches promptly to safeguard systems from potential exploits.. Remote Code Execution,GPG Exploit,SUSE Security Advisory. . Severity: Critical. LinuxSecurity.com Team

Mar 10, 2006 •Critical SuSE