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______________________________________________________________________________
SuSE Security Announcement
Package: Netscape, Versions 4.x, possibly others
Date: Wednesday, August 23rd, 2000 03:30 MEST
Affected SuSE versions: All
Vulnerability Type: remote file viewing, remote buffer overflow
Severity (1-10): 4, 7
SuSE default package: yes
Other affected systems: all linux systems using this package
Content of this advisory:
1) security vulnerability resolved: Netscape
problem description, discussion, solution and upgrade information
2) Correction/apology for perl thread, pending vulnerabilities,
temporary workarounds
3) standard appendix (further information)
<p>______________________________________________________________________________
1) problem description, brief discussion, solution, upgrade information
Two security problems exist in the netscape package as shipped with
SuSE Linux distributions.
a) Improper verification in Netscape's jpeg processing code can lead
to a buffer overflow where data read from the network can overwrite
memory. As a result, arbitrary code from a remote origin could be
executed. The attack is particularly dangerous since it can penetrate
firewall setups. Netscape version 4.74 fixes (fixed) this
vulnerability.
b) Due to an error in the java implementation in Netscape, it is
possible for an attacker to view files and directories with the
priviledges of the user running Netscape if the user visits a
malisciously crafted webpage. This issue is known as "Brown
Orifice" and requires the user to have Java enabled in her browser
configuration. Again, this attack can penetrate firewall setups.
See http://www.brumleve.com/BrownOrifice for details.
Problem a) can be circumvented by disabling the automatic image
loading in Netscape's configuration.
The temporary workaround for problem b) is to disable Java in
Netscape's configuration menu (to protect against other
vulnerabilities, disable JavaScript, too!). Both countermeasures
may widely be found inacceptable.
<p> SuSE provides an updated package for the vulnerable software. It is
strongly recommended to upgrade to the latest version found on our
ftp server as described below. The update package introduces
Netscape version 4.75, including the SuSE-specific libraries that fix
some of Netscape's "irregular" behaviour. Please note that
Netscape-4.75 is not available for the glibc-2.0-based SuSE
Distributions SuSE-6.0 and 6.1 because Netscape doesn't provide
any files for this glibc version. For these distributions, we
provide Netscape Version 4.74 which fixes problem a) only.
Alternatively, the package for the libc5-based SuSE-5.3
distribution can be used as well if the package 'shlibs5' is
installed. This is recommended, since the 5.3 package may be
faster and more reliable.
<p> Download the update package as described below and install the
package with the command `rpm -Fhv file.rpm'. The md5sum for each
file is in the line below. You can verify the integrity of the rpm
files using the command
`rpm --checksig --nogpg file.rpm',
independently from the md5 signatures below.
Due to US-American export restrictions for cryptographical software,
we are unable to provide update packages on our US ftp server
ftp.suse.com. Instead, the packages can be found on ftp.suse.de. For
bandwidth reasons, please use our mirrors or our primary mirror
ftp.gwdg.de and follow the directory to your distribution.
Example: For SuSE-6.4 use the path
ftp://ftp.gwdg.de/pub/linux/suse/6.4_update_de/xap1/netscape.rpm.
***********************************************************************
Please note that the path to netscape.rpm in the 6.0 and 6.1 update
directories point to Netscape version 4.74 which doesn't fix problem b!
See section above!
***********************************************************************
Further mirrors can be found at
http://www.suse.de/de/support/download/ftp/inland.html, but be
advised that not all sites mirror the German part of the update
directories.
md5sums for the i386 Intel Platform (the only one supported):
SuSE Versions 6.2, 6.3, 6.4, 7.0:
70289f88b4c9fc1a9867ba7dac985982 netscape-4.75.glibc21.i386.rpm
SuSE Version 5.3 (libc5-based, probably faster, can be used on
glibc2-based systems if the package shlibs5 is installed)
679aaf67592244a07733bdabdab67729 netscape-4.75.libc5.i386.rpm
SuSE Version 6.0 and 6.1, Netscape-4.74 with incomplete fixes:
4bcc31fe37f7c8d226b437c1daa9b944 netscape-4.74.glibc20.i386.rpm
<p>______________________________________________________________________________
2) Correction/Apology: In my posting to suse-security@suse.de and to
bugtraq@securityfocus.com about the suidperl thread, Subject: "SuSE
Security Announcement: suidperl (perl)", dated 10 Aug 2000, I wrote:
"A maliciously implemented feature causes the interpreter to spawn
the /bin/mail program to"..."
This is a bad and embarrassing mistake because of a confusion about
the word "maliciously" in this context - it was meant to read
"inconsiderate".
I apologize to the perl folks for this mistake.
<p> Pending vulnerabilities in SuSE Distributions and Workarounds:
This section addresses currently known vulnerabilities in Linux/Unix
systems that have not been resolved yet as of the release date of
this advisory.
- ntop
ntop is a network statistics visualization utility which offers
graphical analysis of network traffic and other statistics with
a web browser. By default, ntop listens on port 3000 and requires
no or a commonly known authentication password to view the data.
ntop is only installed in network server selections and is not
activated by default in SuSE Linux installations.
The ntop packages shipped with SuSE Linux did not exhibit the
unsafe behaviour when a file like /../../etc/passwd is referenced.
However, Thomas Biege has reviewed the source of the package and
there are still some potential problems with the package that
require a major overhaul of the code.
Currently, we recommend to disable or even remove the ntop package
(`rpm -e ntop') in an environment where security considerations
play a role. More information on ntop can be found in
ntop's documentation directory /usr/doc/packages/ntop or
/usr/share/doc/packages/ntop for SuSE-7.0.
- zope
SuSE distributions before 7.0 do not contain zope as a package.
An updated package for the freshly released SuSE-7.0 is on the way.
- xchat
A fix for the URL handler vulnerabilty is in progress and will
be released within a few days. There is currently no effective
and easy workaround other than removing the package by hand
(`rpm -e xchat'). More information on xchat can be found in
xchat's documentation directory /usr/doc/packages/xchat or
/usr/share/doc/packages/xchat for SuSE-7.0.
- minicom
SuSE's minicom doesn't exhibit the problem with files created
belonging to group uucp because /usr/bin/minicom isn't installed
sgid uucp by default. Changing this to 2755 root.uucp (manually
and in /etc/permissions) doesn't show any defective behaviour
either.
- xlockmore: After a review of the relevant part of xlock's code
we've found that the format string parsing bug posted by
bind@SUBTERRAIN.NET on bugtraq on August 15th 2000 is not
critical wrt security. xlock drops all privs as soon as it could
get hold of the user's encrypted password (which is before it
crashes). Other encrypted passwords can't be found in xlock's
memory. Since xlock on SuSE distributions runs sgid shadow, it
can't dump a core file upon segmentation fault (search
/usr/src/linux/kernel/sys.c for "dumpable".) and also can't be
traced (/usr/src/linux/arch/i386/kernel/ptrace.c).
The bug will be fixed in future releases of the SuSE Linux
distribution.
The following packages are not contained in SuSE distributions.
Therefore, they do not impose any security risks on SuSE systems
unless an administrator installed (compiled) the vulnerable
software by hand.
- FlagShip permissions, from Narrow