Linux-Mandrake Security Update Advisory: modutils update
Nov 24, 2000, 09:17 (0 Talkback[s])
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Date: Thu, 23 Nov 2000 13:36:06 -0700
From: Linux Mandrake Security Team email@example.com
To: Linux Mandrake Security Announcements
Subject: [Security Announce] MDKSA-2000:071-1 - modutils update
Linux-Mandrake Security Update Advisory
Package name: modutils
Date: November 23rd, 2000
Original Advisory Date: November 16th, 2000
Advisory ID: MDKSA-2000:071-1
Affected versions: 7.1, 7.2
All 2.3.x versions of modutils (since March 12 1999) contain a
vulnerability that can lead to a local root compromise. The
modprobe program uses popen() to execute the "echo" program
argumented with user input. Because popen() relies on /bin/sh to
parse the command string and execute "echo", un-escaped shell
meta-characters can be included in user input to execute commands.
Although modprobe is not installed setuid root, this vulnerability
can be exploited to gain root access provided the target system is
using kmod. Kmod is a kernel facility that automatically executes
the program modprobe when a module is requested via
request_module(). One program that can take advantage of this
vulnerability is ping. When a device is specified at the command
line that doesn't exist, request_module is called with the
user-supplied arguments passed to the kernel. The kernel then takes
the arguments and executes modprobe with them. Arbitrary commands
included in the argument for module name (device name to ping) are
then executed when popen() is called as root.
A new version of modutils (2.3.20) has been released that fixes
this particular vulnerability. modutils still supports meta
expansion, including back quoted commands, but only for data read
from the configuration file. This assumes that when modutils is run
as root out of the kernel, normal users cannot specify their own
The previous version of modutils (2.3.20) contained an error in
the new safe guards that caused them to not properly be enabled
when run as root from the kmod process. These new safe guards check
the arguments passed to modules. The 2.3.21 modutils package fixes
this error and correctly checks the arguments when running from
kmod, limiting kernel module arguments to those specified in
/etc/conf.modules (Linux-Mandrake 7.1) or /etc/modules.conf
Please verify these md5 checksums of the updates prior to
upgrading to ensure the integrity of the downloaded package. You
can do this by running the md5sum program on the downloaded package
by using "md5sum package.rpm".
To upgrade automatically, use
If you want to upgrade manually, download the updated package
from one of our FTP server mirrors and uprade with "rpm -Uvh
You can download the updates directly from:
Or try one of the other mirrors listed at:
Updated packages are available in the "updates/[ver]/RPMS/"
directory. For example, if you are looking for an updated RPM
package for Linux-Mandrake 7.1, look for it in "updates/7.1/RPMS/".
Updated source RPMs are available as well, but you generally do not
need to download them.
Please be aware that sometimes it takes the mirrors a few hours
to update, so if you want an immediate upgrade, please use one of
the two above-listed mirrors.
You can view other security advisories for Linux-Mandrake
If you want to report vulnerabilities, please contact
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