GLSA 200407-12: Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling

http://security.gentoo.org/

Опасность:	высокая
Заголовок:	Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling
Дата:	14.07.2004
Ошибки:	#55694
ID:	200407-12

Сводка

A flaw has been discovered in 2.6 series Linux kernels that allows an attacker to send a malformed TCP packet, causing the affected kernel to possibly enter an infinite loop and hang the vulnerable machine.

Назначение

The Linux kernel is responsible for managing the core aspects of a GNU/Linux system, providing an interface for core system applications as well as providing the essential structure and capability to access hardware that is needed for a running system.

Уязвимые пакеты

Пакет	Уязвимый	Нетронутый	Архитектура(ы)
sys-kernel/aa-sources	< 2.6.5-r5	>= 2.6.5-r5	All supported architectures
sys-kernel/ck-sources	< 2.6.7-r2	>= 2.6.7-r2	All supported architectures
sys-kernel/development-sources	< 2.6.8	>= 2.6.8	All supported architectures
sys-kernel/gentoo-dev-sources	< 2.6.7-r7	>= 2.6.7-r7	All supported architectures
sys-kernel/hardened-dev-sources	< 2.6.7-r1	>= 2.6.7-r1	All supported architectures
sys-kernel/hppa-dev-sources	< 2.6.7_p1-r1	>= 2.6.7_p1-r1	All supported architectures
sys-kernel/mips-sources	< 2.6.4-r4	>= 2.6.4-r4	All supported architectures
sys-kernel/mm-sources	< 2.6.7-r4	>= 2.6.7-r4	All supported architectures
sys-kernel/pegasos-dev-sources	< 2.6.7-r1	>= 2.6.7-r1	All supported architectures
sys-kernel/rsbac-dev-sources	< 2.6.7-r1	>= 2.6.7-r1	All supported architectures
sys-kernel/uclinux-sources	< 2.6.7_p0	>= 2.6.7_p0-r1	All supported architectures
sys-kernel/usermode-sources	< 2.6.6-r2	>= 2.6.6-r2	All supported architectures
sys-kernel/win4lin-sources	< 2.6.7-r1	>= 2.6.7-r1	All supported architectures
sys-kernel/xbox-sources	< 2.6.7-r1	>= 2.6.7-r1	All supported architectures

Описание

An attacker can utilize an erroneous data type in the IPTables TCP option handling code, which lies in an iterator. By making a TCP packet with a header length larger than 127 bytes, a negative integer would be implied in the iterator.

Воздействие

By sending one malformed packet, the kernel could get stuck in a loop, consuming all of the CPU resources and rendering the machine useless, causing a Denial of Service. This vulnerability requires no local access.

Обход

If users do not use the netfilter functionality or do not use any ``--tcp-option'' rules they are not vulnerable to this exploit. Users that are may remove netfilter support from their kernel or may remove any ``--tcp-option'' rules they might be using. However, all users are urged to upgrade their kernels to patched versions.

Решение

Users are encouraged to upgrade to the latest available sources for their system:

    # emerge sync
    # emerge -pv your-favorite-sources
    # emerge your-favorite-sources

    # # Follow usual procedure for compiling and installing a kernel.
    # # If you use genkernel, run genkernel as you would do normally.

Ссылки

CAN-2004-0626

Наличие

Этот GLSA и любые обновления для нее доступны для просмотра на сайте Gentoo Security: http://security.gentoo.org/glsa/glsa-200407-12.xml

Опасения?

Безопасность является одной из главных задач Gentoo Linux и первостепенное значение обеспечить конфиденциальность и безопасность машин наших пользователей. Любые соображения безопасности должны быть адресованы security@gentoo.org или в качестве альтернативы, вы можете сообщить об ошибке на https://bugs.gentoo.org.