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SuSE Linux Advisory: glibc

May 27, 2003, 18:59 (0 Talkback[s])

SuSE Security Announcement

Package: glibc
Announcement-ID: SuSE-SA:2003:027
Date: Monday, May 26th 2003 16:12 MET
Affected products: 7.1, 7.2, 7.3, 8.0, 8.1, SuSE Linux Database Server, SuSE eMail Server III, 3.1 SuSE Linux Enterprise Server 7, SuSE Linux Firewall on CD/Admin host SuSE Linux Connectivity Server SuSE Linux Office Server
Vulnerability Type: remote system compromise
Severity (1-10): 6
SuSE default package: yes
Cross References: CAN-2003-0028

Content of this advisory:

  1. security vulnerability resolved: integer overflow in XDR code problem description, discussion, solution and upgrade information
  2. pending vulnerabilities, solutions, workarounds:
    • ethereal
    • XFree4
    • vnc
    • bitchx
    • lv
  3. standard appendix (further information)

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

Another integer overflow was found in glibc' XDR code. This bug is equal to the one described in advisory SuSE-SA:2002:031. The overflow occurs in the function xdrmem_getbytes() and can be used by external attackers to execute arbitrary code.

There is no temporary workaround for this security problem other than disabling all RPC based server and client programs. The permanent solution is to update the glibc packages with the update packages listed below.

Notes, Special installation instructions:

  • PRECAUTIONS The shared libraries package of the glibc is the most sensitive part of a running Linux system, and modifications to it should be handled with special care. During the update of the shlibs/glibc package, runtime-linking the shared libraries is likely to fail for processes that execute a new binary with the execve(2) system call. Therefore, we recommend to bring a system to single user mode ("init S") to perform the package update. If this is not applicable for operational reasons, a system receiving the update should be kept as quiet as possible (no shell scripts of any kind, no cron jobs, no incoming email).
  • After performing the update, you should run the following command on your system:

    /sbin/ldconfig ldconfig will rebuild the runtime linker cache. If you use YOU (Yast2 Online Update), the ldconfig command will be executed automatically at the end of the update.

The shared libraries that were installed on the system before the update have been removed from the filesystem, but they are still in use by the running applications. Therefore, the disk-space as well as the memory will not be freed until the last process that uses these files exits. We recommend to reboot the system to workaround this problem.

Listed below you find the URLs for the update packages for the SuSE Linux products. We only list the packages that are relevant for the security update. Our maintenance customers are being notified individually. The packages are being offered to install from the maintenance web.

Intel i386 Platform:

SuSE-8.1:
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i686/glibc-2.2.5-177.i686.rpm 1cf549fa52427710c7dc3316fc5df4a6
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i686/glibc-2.2.5-177.i686.patch.rpm f87601fd71edf54928104581684dae8f

SuSE-8.0:
ftp://ftp.suse.com/pub/suse/i386/update/8.0/a1/glibc-2.2.5-177.i386.rpm da51402d30c37dd5dc6d5444c37f4dc3
patch rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/a1/glibc-2.2.5-177.i386.patch.rpm 0b5ea57d89c31d923cfb56cb1f951bac
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/glibc-2.2.5-177.src.rpm 6fecec2ed42fb792b6e9cb2a5602fe23

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/i386/update/7.3/a1/glibc-2.2.4-78.i386.rpm 11cc1ceb173b18fc82d8500b1528663e
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.3/zq1/glibc-2.2.4-78.src.rpm 38527e5f75d94c016659c71028c37c52

SuSE-7.2:
ftp://ftp.suse.com/pub/suse/i386/update/7.2/a1/glibc-2.2.2-68.i386.rpm 82f4c3ee8ba0cf3feef5e0ba7321a230
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.2/zq1/glibc-2.2.2-68.src.rpm 34114134cb51d706989c45306f4fdde3

SuSE-7.1:
ftp://ftp.suse.com/pub/suse/i386/update/7.1/a1/glibc-2.2-26.i386.rpm ffe7c422727ee98b8191facbbf40b9d7
source rpm(s):
ftp://ftp.suse.com/pub/suse/i386/update/7.1/zq1/glibc-2.2-26.src.rpm 1c5b778ff60a82f03e412239b907671b

Sparc Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/a1/glibc-2.2.4-46.sparc.rpm dc577491e13344411462603b6fe83d3f
source rpm(s):
ftp://ftp.suse.com/pub/suse/sparc/update/7.3/zq1/glibc-2.2.4-46.src.rpm 0a0a5dd6ee76e6b0ef866b500d6537b2

AXP Alpha Platform:

SuSE-7.1:
ftp://ftp.suse.com/pub/suse/axp/update/7.1/a1/glibc-2.2-34.alpha.rpm d250c254668e02b9f23341903f2f3a5e
source rpm(s):
ftp://ftp.suse.com/pub/suse/axp/update/7.1/zq1/glibc-2.2-34.src.rpm d89b4a1ff27227a085e516b48ccdb1cf

PPC Power PC Platform:

SuSE-7.3:
ftp://ftp.suse.com/pub/suse/ppc/update/7.3/a1/glibc-2.2.4-69.ppc.rpm 5bf4edf432c996b3e38ef085122e1e8


  1. Pending vulnerabilities in SuSE Distributions and Workarounds:
  • ethereal
    Several one-byte buffer overflows and integer overflows are fixed. These bugs lead to remote denial-of-service or even remote code execution. New packages are available on our FTP servers.
  • XFree4
    A buffer overflow in the Xlib code can be triggered while handling the environment variable XLOCALEDIR. The X version affected is 4.2.0 (SuSE Linux 8.0 and 8.1). New packages are available on our FTP servers.
  • vnc
    VNC (Virtual Network Computing) uses a weak cookie generation process which can be exploited by an attacker to bypass authentication. New packages are available on our FTP servers.
  • bitchx
    Several buffer overflows got fixed that can be exploited remotely by a malicious IRC servers. New packages are available on our FTP servers.
  • lv
    lv reads config files from the current directory without verifying the ownership. If lv is called in world-writeable directories like /tmp it can be tricked into executing commands by putting a malicious config file there. New packages are available on our FTP servers.

  1. 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 <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.
  2. 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:

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,Deutschherrnstr. 15-19,90429 Nuernberg Function: Security Support & Auditing "lynx -source http://www.suse.de/~thomas/contact/thomas.asc | gpg --import" Key fingerprint = 7254 B15D B3C4 943F 485E 0BBD 8ECC D7CB C200 A213


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