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SUSE Linux Advisory: lftp

Dec 15, 2003, 16:56 (0 Talkback[s])

SUSE Security Announcement

Package: lftp
Announcement-ID: SuSE-SA:2003:051
Date: Monday, Dec 15th 2003 14:30 MET
Affected products: 8.2, 9.0 remote system compromise
Severity (1-10): 3
SUSE default package: no
Cross References:  

Content of this advisory:

  1. security vulnerability resolved:
    • local buffer overflow problem description, discussion, solution and upgrade information
  2. pending vulnerabilities, solutions, workarounds:
    • mc
    • mod_gzip
    • freeradius
    • tripwire
    • cvs
    • irssi
    • atftp
  3. standard appendix (further information)

1) problem description, brief discussion, solution, upgrade information

The the flexible and powerful FTP command-line client lftp is vulnerable to two remote buffer overflows.
When using lftp via HTTP or HTTPS to execute commands like 'ls' or 'rels' specially prepared directories on the server can trigger a buffer overflow in the HTTP handling functions of lftp to possibly execute arbitrary code on the client-side.
Please note, to exploit these bugs an attacker has to control the serverside of the context and the attacker will only gain access to the account of the user that is executing lftp.

There is no temporary workaround known.

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.

Intel i386 Platform:

SuSE-9.0:
ftp://ftp.suse.com/pub/suse/i386/update/9.0/rpm/i586/lftp-2.6.6-71.i586.rpm 2e5aee46868b5b19c26a8559927e8663
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/9.0/rpm/i586/lftp-2.6.6-71.i586.patch.rpm 0468cf8f2b2b4c18a854f51ef63470b7
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/9.0/rpm/src/lftp-2.6.6-71.src.rpm a32eee3ff4eeb322d44f04b9f8ff4c9c

SuSE-8.2:
ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/lftp-2.6.4-44.i586.rpm df0d7c059cd3bb4fe47c927849fd9a5e
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/lftp-2.6.4-44.i586.patch.rpm eb9d6aedc25d3e2d25b63999526ee1bd
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/src/lftp-2.6.4-44.src.rpm 63695b02bf520b02f93ec73078d6e4d8


2) Pending vulnerabilities in SUSE Distributions and Workarounds:

  • mc
    By using a special combination of links in archive-files it is possible to execute arbitrary commands while mc tries to open it in its VFS. The packages are currently tested and will be release as soon as possible.
  • mod_gzip
    The apache module mod_gzip is vulnerable to remote code execution while running in debug-mode. We do not ship this module in debug-mode but future versions will include the fix. Additionally the mod_gzip code was audited to fix more possible security related bugs.
  • freeradius
    Two vulnerabilities were found in the FreeRADIUS package. The remote denial-of-service attack bug was fixed and new packages will be released as soon as testing was successfully finished. The other bug is a remote buffer overflow in the module rlm_smb. We do not ship this module and will fix it for future releases.
  • tripwire
    Tripwire is a file integrity checker. The tripwire version on SuSE Linux 8.2 and 9.0 do crash when a requested file does not exists. New packages will be available soon.
  • cvs
    The cvs server-side can be tricked to create files in the root filesystem of the server by requesting malformed modules. The permissions on the root filesystem normally prevent this malfunction. New packages will be available soon.
  • irssi
    Under special circumstances the the irc-client irssi can be crashed remotely by other irc-clients. A fix will be available soon.
  • atftp
    A buffer overflow vulnerability discovered by Rick Patel has been fixed in the atftpd (trivial file transfer protocol, UDP oriented) daemon, contained in the atftp package. Update packages for the affected SUSE Linux distributions 8.1 and 8.2 have been published on our ftp server today. We explicitly thank Dirk Mueller, KDE developer, for notifying SUSE Security about the pending treatment of this incident.

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.
    3. execute the command md5sum <name-of-the-file.rpm> 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 security@suse.de), the checksums show proof of the authenticity of the package. We disrecommend to subscribe 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.
    4. rpm package signatures provide an easy way to verify the authenticity of an rpm package. Use the command rpm -v --checksig <file.rpm> to verify the signature of the package, where <file.rpm> 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:
      1. gpg is installed
      2. 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 "build@suse.de" 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 ftp://ftp.suse.com/pub/suse/pubring.gpg-build.suse.de .
  • SUSE runs two security mailing lists to which any interested party may subscribe:

    suse-security@suse.com

  • general/linux/SUSE security discussion. All SUSE security announcements are sent to this list. To subscribe, send an email to

    <suse-security-subscribe@suse.com>.

    suse-security-announce@suse.com

  • SUSE's announce-only mailing list. Only SUSE's security announcements are sent to this list. To subscribe, send an email to

    <suse-security-announce-subscribe@suse.com>.

For general information or the frequently asked questions (faq) send mail to:

<suse-security-info@suse.com> or
<suse-security-faq@suse.com> respectively.


SUSE's security contact is <security@suse.com> or <security@suse.de>. The <security@suse.de> 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 <security@suse.de>
pub 1024D/9C800ACA 2000-10-19 SuSE Package Signing Key <build@suse.de>

Bye,

Thomas
--
Thomas Biege <thomas@suse.de>, SUSE LINUX AG, Security Support & Auditing