Mandrake Linux Security Advisory : kernel22 (MDKSA-2003:039)
High Nessus Plugin ID 14023
SynopsisThe remote Mandrake Linux host is missing one or more security updates.
DescriptionA number of vulnerabilities have been found in the Linux 2.2 kernel that have been addressed with the latest 2.2.25 release.
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.
As well, multiple ethernet device drivers do not pad frames with null bytes, which could allow remote attackers to obtain information from previous packets or kernel memory by using malformed packets.
Finally, the 2.2 kernel allows local users to cause a crash of the host system by using the mmap() function with a PROT_READ parameter to access non-readable memory pages through the /proc/pid/mem interface.
All users are encouraged to upgrade to the latest kernel version provided.
For instructions on how to upgrade your kernel in Mandrake Linux, please refer to :
SolutionUpdate the affected packages.