SuSE Linux Advisory: sendmail

SuSE Security Announcement

Content of this advisory:

1. security vulnerability resolved: calling free() with arbitrary

   argument problem description, discussion, solution and upgrade
   information

2. pending vulnerabilities, solutions, workarounds:
   • traceroute(-nanog)
   • gdm2
   • pam_smb
   • exim
3. standard appendix (further information)

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

The well known and widely used MTA sendmail is vulnerable to a
remote denial-of-service attack in version 8.12.8 and earlier (but
not before 8.12). The bug exists in the DNS map code. This feature
is enabled by specifying FEATURE(`enhdnsbl’). When sendmail
receives an invalid DNS response it tries to call free(3) on random
data which results in a process crash.

After your system was updated you have to restart your sendmail
daemon to make the update effective.

There is no known workaround for this vulnerability other than
using a different MTA.

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-8.2:

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/sendmail-8.12.7-73.i586.rpm
eaf90e49886f496b2779107f1d9a831a
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/sendmail-8.12.7-73.i586.patch.rpm
c5999fe4026e05c4308249a7e3dbf8f4
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/src/sendmail-8.12.7-73.src.rpm
2cda6c535a3be4e26c50373bd078b4c7

SuSE-8.1:

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-147.i586.rpm
03d2b6e1083f863dc19a28f44256b071
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/sendmail-8.12.6-147.i586.patch.rpm
ee6a3553396432bd3a208d355dacdd33
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/sendmail-8.12.6-147.src.rpm
97417cee623251c6cc3009c13c5b1fbe

SuSE-8.0:

ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-76.i386.rpm
c7cd791bdbcf0c5ed80cd9aab0ccc965
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.0/n1/sendmail-8.12.3-76.i386.patch.rpm
a2d04f73894a09b9134f0f516c385d78
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sendmail-8.12.3-76.src.rpm
4c059b5714ba2dbe5860654622b65bfb

Intel i386 Platform:

SuSE-8.2:

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/uucp-1.06.1-931.i586.rpm
1d5e50aea21f2ce88277fd9113dfb6da
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/i586/uucp-1.06.1-931.i586.patch.rpm
402cff9f2e0e4b56b2409082d0adbc0d
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.2/rpm/src/sendmail-8.12.7-73.src.rpm
2cda6c535a3be4e26c50373bd078b4c7

SuSE-8.1:

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/uucp-1.06.1-931.i586.rpm
7de06e8f16800359e25b5d9dcc739af5
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/i586/uucp-1.06.1-931.i586.patch.rpm
67c84d8cd4ff132ef0c1a91ed845b5d8
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.1/rpm/src/sendmail-8.12.6-147.src.rpm
97417cee623251c6cc3009c13c5b1fbe

SuSE-8.0:

ftp://ftp.suse.com/pub/suse/i386/update/8.0/n4/uucp-1.06.1-931.i386.rpm
b95b64d0c474ee7b37a82e2fc04e72b7
patch rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.0/n4/uucp-1.06.1-931.i386.patch.rpm
e872341553634848bb19b0d89a1e3a37
source rpm(s):

ftp://ftp.suse.com/pub/suse/i386/update/8.0/zq1/sendmail-8.12.3-76.src.rpm
4c059b5714ba2dbe5860654622b65bfb

2) Pending vulnerabilities in SuSE Distributions and
Workarounds:

• traceroute(-nanog) A integer overflow in traceroute can be
  abused by local attackers to gain access to a raw IP socket. New
  packages are available on out FTP servers.
• gdm2 Due to a bug in GDM it is possible for local users to read
  any text file on a system by creating a symlink from
  ~/.xsession-errors. Updated packages will be available on our FTP
  servers soon.
• pam_smb A buffer overflow in the password handling function of
  pam_smb allows remote root compromise. Fixed packages will be
  available soon.
• exim Two bugs where fixed in exim. One bug allows remote access
  as user mail/mail and the other one allows local root access for
  ‘Admin Users’. Fixed packages are available on our FTP
  servers.

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 [email protected]), 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 “[email protected]”
      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:

[email protected]

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

  <[email protected]>.

[email protected]

• SuSE’s announce-only mailing list. Only SuSE’s security
  announcements are sent to this list. To subscribe, send an email to
  <[email protected]>.

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

<[email protected]>
or
<[email protected]>
respectively.

SuSE’s security contact is <[email protected]> or
<[email protected]>. The
<[email protected]>
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.

Bye,

Thomas
—
Thomas Biege <[email protected]>