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SuSE: 2002:040 Moderate: lprng Command Execution Vulnerability Alert

There is a vulnerability where local attackers can pass certain commandline arguments to lpr running as root, fooling it to execute arbitrary commands as root.. ______________________________________________________________________________ SuSE Security Announcement Package: lprng, html2ps Announcement-ID: SuSE-SA:2002:040 Date: Thu Oct 31 11:00:10 MET 2002 Affected products: 7.0, 7.1, 7.2, 7.3, 8.0, 8.1 SuSE eMail Server III, 3.1 SuSE Firewall on CD/Admin host SuSE Firewall on CD 2 SuSE Linux Connectivity Server SuSE Linux Enterprise Server 7 SuSE Linux Office Server Vulnerability Type: local privilege escalation, remote command execution Severity (1-10): 6 SuSE default package: yes Cross References: - Content of this advisory: 1) security vulnerability resolved: Local privilege escalation in runlpr (from lprng package) and remote command execution via html2ps printfilter. problem description, discussion, solution and upgrade information 2) pending vulnerabilities, solutions, workarounds: - 3) standard appendix (further information) ______________________________________________________________________________ 1) problem description, brief discussion, solution, upgrade information The lprng package contains the "runlpr" program which allows the lp user to execute the lpr program as root. Local attackers can pass certain commandline arguments to lpr running as root, fooling it to execute arbitrary commands as root. This has been fixed. Note that this vulnerability can only be exploited if the attacker has previously gained access to the lpaccount. Additionally, the html2ps printfilter, which is installed as part of the LPRng print system, allowed remote attackers to execute arbitrary commands in the context of the lp user. These two issues combined allow attackers to mount a remote root attack. As a workaround, we recommend to uninstall the html2ps package, and restrict access to your print services to authorized hosts only. Access control to lpd is implemented by adding appropriate entries to the /etc/lpd.perms file. Please consult the lpd.perms(5) manpage, or add the single line DEFAULT REJECT to your /etc/lpd.perms file to deny access to everyone from the outside. Please download the update package for your distribution and verify its integrity by the methods listed in section 3) of this announcement. Then, install the package using the command "rpm -Fhv file.rpm" to apply the update. Our maintenance customers are being notified individually. The packages are being offered to install from the maintenance web. i386 Intel Platform: SuSE-8.1 c1990d8139e33176fb02745f3e5b0a05 source rpm: f42f18d885dc2fe5701bc74812fd6ceb cc79a87fd8fcc9cf92356ab4863babc6 source rpm: 0ad433931936c4ba5a644de9104b3db4 SuSE-8.0 c14c59d1f23575841a95f7d5eaf6f734 source rpm: 7ffd5b01e399ee427a0d3a16d15af4f1 dd04dd60c4c18b5711643f6334b97bfd source rpm: 4d6b611c572d251f47c0b4cf8ab7a28d SuSE-7.3 28a1aee8dfedfff3eb348fc4ea4a8876 source rpm: 2765c61e39616199cbf5066d719280b3 SuSE-7.2 1ab553d151c65505184353ae6e514db6 source rpm: b71dba7782caeb01954b418e3ffdd6c2 SuSE-7.1 1d9adfc7cc1e141f340b844f040bfe85 source rpm: b1b29ff154fc13cb806dec49fc00ff81 SuSE-7.0 7e0bd236c647cd70ba9b0274f7b5cf53 source rpm: b60e012d057e428e6ade468d46afd4e5 Sparc Platform: SuSE-7.3 b6c1c7399a041477ce0c321a9eda383b source rpm: 8102e2145e43fb6486cee5ccfc106c67 AXP Alpha Platform: SuSE-7.0 83967dc5d7dcf672c6dd902c125a3e81 source rpm: e3851c0f69017811168213a707431467 PPC Power PC Platform: SuSE-7.1 b9cb5de37503927812f767a0781bfc6a source rpm: be58c62e270d5cbc2aa3395beae91009 SuSE-7.0 a98f5628ae1068b3d7f20b83ace9bb77 source rpm: 5a425dbc64f2e0f2a368ecb566c624eb ______________________________________________________________________________ 2) Pending vulnerabilities in SuSE Distributions and Workarounds: There is no additional information this time. ______________________________________________________________________________ 3) standard appendix: authenticity verification, additional information - Package authenticity verification: SuSE update packages are available on many mirror ftp servers all over the world. While this service is being considered valuable and important to the free and open source software community, many users wish to be sure about the origin of the package and its content before installing the package. 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) md5sums as provided in the (cryptographically signed) announcement. 2) using the internal gpg signatures of the rpm package. 1) 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 announcement. Since the announcement containing the checksums is cryptographically signed (usually using the key 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. We disrecommend tosubscribe to security lists which cause the email message containing the announcement to be modified so that the signature does not match after transport through the mailing list software. Downsides: You must be able to verify the authenticity of the announcement in the first place. If RPM packages are being rebuilt and a new version of a package is published on the ftp server, all md5 sums for the files are useless. 2) 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, where is the filename of the rpm package that you have downloaded. Of course, package authenticity verification can only target an un-installed rpm package file. Prerequisites: a) gpg is installed b) The package is signed using a certain key. The public part of this key must be installed by the gpg program in the directory ~/.gnupg/ under the user's home directory who performs the signature verification (usually root). You can import the key that is used by SuSE in rpm packages for SuSE Linux by saving this announcement to a file ("announcement.txt") and running the command (do "su -" to be root): gpg --batch; gpg < announcement.txt | gpg --import SuSE Linux distributions version 7.1 and thereafter install the key " This email address is being protected from spambots. You need JavaScript enabled to view it. " upon installation or upgrade, provided that the package gpg is installed. The file containing the public key is placed at the top-level directory of the first CD (pubring.gpg) and at . - SuSE runs two security mailing lists to which any interested party may subscribe: This email address is being protected from spambots. You need JavaScript enabled to view it. - general/linux/SuSE security discussion. All SuSE security announcements are sent to this list. To subscribe, send anemail 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 email to . For general information or the frequently asked questions (faq) send mail to: or respectively. ==================================================================== SuSE's security contact is or . The public key is listed below. ====================================================================______________________________________________________________________________ The information in this advisory may be distributed or reproduced, provided that the advisory is not modified in any way. In particular, it is desired that the clear-text signature shows proof of the authenticity of the text. SuSE Linux AG makes no warranties of any kind whatsoever with respect to the information contained in this security advisory. Type Bits/KeyID Date User ID pub 2048R/3D25D3D9 1999-03-06 SuSE Security Team pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key . Critical update from SuSE addressing vulnerabilities related to local privilege escalation and potential remote code execution threats.. SuSE Security Announcement,lprng Package Update,Command Execution Risk. . LinuxSecurity.com Team

Oct 31, 2002 SuSE