Mandrake: kernel ptrace vulnerability
Posted by Team   
Mandrake A bug in the kernel module loader code could allow a local user to gain root privileges.


                Mandrake Linux Security Update Advisory

Package name:           kernel
Advisory ID:            MDKSA-2003:038
Date:                   March 27th, 2003

Affected versions:	9.0, Corporate Server 2.1

Problem Description:

 A bug in the kernel module loader code could allow a local user to gain 
 root privileges.  This is done by a local user using ptrace and 
 attaching to a modprobe process that is spawned if the user triggers 
 the loading of a kernel module.
 A temporary workaround can be used to defend against this flaw.  It is 
 possible to temporarily disable the kmod kernel module loading 
 subsystem in the kernel after all of the required kernel modules have 
 been loaded.  Be sure that you do not need to load additional kernel 
 modules after implementing this workaround. To use it, as root execute:
   echo /no/such/file >/proc/sys/kernel/modprobe
 To automate this, you may wish to add it as the last line of the 
 /etc/rc.d/rc.local file.  You can revert this change by replacing the 
 content "/sbin/modprobe" in the /proc/sys/kernel/modprobe file.  The 
 root user can still manually load kernel modules with this workaround 
 in place.
 This update applies a patch to correct the problem.  All users should 
 upgrade.  Please note that the Mandrake Linux 9.1 kernel already has 
 this patch, and an updated kernel for Mandrake Linux 8.2 will be 
 available shortly.
 For instructions on how to upgrade your kernel in Mandrake Linux,
 please refer to:


Updated Packages:
 Corporate Server 2.1:
 f3c1c5e6b9a677019cfe7094ff804c10  corporate/2.1/RPMS/kernel-
 3dcd13d22100c30d88ddfc4294baa9e4  corporate/2.1/RPMS/kernel-BOOT-
 2949fd7c641662835d2f3eb54b1fd884  corporate/2.1/RPMS/kernel-enterprise-
 333689546094a5fc804ee7f5d1c4aecf  corporate/2.1/RPMS/kernel-secure-
 d4ad9d24d072d188afbc353cda4206b7  corporate/2.1/RPMS/kernel-smp-
 4b611461a5aac876e41516948dadb710  corporate/2.1/RPMS/kernel-source-2.4.19-32mdk.i586.rpm
 58f41baa7913134f719de3ae7d834ee8  corporate/2.1/SRPMS/kernel-

 Mandrake Linux 9.0:
 f3c1c5e6b9a677019cfe7094ff804c10  9.0/RPMS/kernel-
 3dcd13d22100c30d88ddfc4294baa9e4  9.0/RPMS/kernel-BOOT-
 2949fd7c641662835d2f3eb54b1fd884  9.0/RPMS/kernel-enterprise-
 333689546094a5fc804ee7f5d1c4aecf  9.0/RPMS/kernel-secure-
 d4ad9d24d072d188afbc353cda4206b7  9.0/RPMS/kernel-smp-
 4b611461a5aac876e41516948dadb710  9.0/RPMS/kernel-source-2.4.19-32mdk.i586.rpm
 58f41baa7913134f719de3ae7d834ee8  9.0/SRPMS/kernel-

Bug IDs fixed (see for more information):

To upgrade automatically, use MandrakeUpdate.  The verification of md5
checksums and GPG signatures is performed automatically for you.

If you want to upgrade manually, download the updated package from one
of our FTP server mirrors and upgrade with "rpm -Fvh *.rpm".  A list of
FTP mirrors can be obtained from:

Please verify the update prior to upgrading to ensure the integrity of
the downloaded package.  You can do this with the command:

  rpm --checksig 

All packages are signed by MandrakeSoft for security.  You can obtain
the GPG public key of the Mandrake Linux Security Team from:

Please be aware that sometimes it takes the mirrors a few hours to

You can view other update advisories for Mandrake Linux at:

MandrakeSoft has several security-related mailing list services that
anyone can subscribe to.  Information on these lists can be obtained by

If you want to report vulnerabilities, please contact

Type Bits/KeyID     Date       User ID
pub  1024D/22458A98 2000-07-10 Linux Mandrake Security Team