From: Genco YILMAZ (gyilmaz@genco.gen.tc)
Date: Thu 15 Jul 2004 - 01:08:15 EEST
ilgilenenlere...
----------------------------- Orijinal Mesaj -----------------------------
Konu: [gentoo-announce] [ GLSA 200407-12 ] Linux Kernel: Remote DoS
vulnerability with IPTablesTCP Handling Gönderen: "Tim Yamin"
<plasmaroo@gentoo.org>
Tarih: 15 Temmuz 2004, Perşembe, 12:04 am
Alıcı: gentoo-announce@lists.gentoo.org
Kk: bugtraq@securityfocus.com
full-disclosure@lists.netsys.com
security-alerts@linuxsecurity.com
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Gentoo Linux Security Advisory GLSA 200407-12 -
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http://security.gentoo.org/
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Severity: High
Title: Linux Kernel: Remote DoS vulnerability with IPTables TCP
Handling
Date: July 14, 2004
Bugs: #55694
ID: 200407-12
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Synopsis
=======
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.
Background
=========
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.
Affected packages
================
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Kernel / Unaffected / Remerge
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1 aa-sources ............... >= 2.6.5-r5 ...................... YES 2
ck-sources ............... >= 2.6.7-r2 ...................... YES 3
gentoo-dev-sources ....... >= 2.6.7-r7 .......................... 4
hardened-dev-sources ..... >= 2.6.7-r1 .......................... 5
hppa-dev-sources ....... >= 2.6.7_p1-r1 ......................... 6
mips-sources ............ *>= 2.6.4-r4 ..........................
.......................... >= 2.6.7-r1 ..........................
7 mm-sources ............... >= 2.6.7-r4 ...................... YES 8
pegasos-dev-sources ...... >= 2.6.7-r1 .......................... 9
rsbac-dev-sources ........ >= 2.6.7-r1 ..........................
10 uclinux-sources ........ >= 2.6.7_p0-r1 ......................... 11
usermode-sources ......... >= 2.6.6-r2 .......................... 12
win4lin-sources .......... >= 2.6.7-r1 .......................... 13
xbox-sources ............. >= 2.6.7-r1 .......................... 14
development-sources ...... Vulnerable! ..........................
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NOTE: Some kernels are still vulnerable. Users should migrate to
another kernel if one is available or seek another
solution such as patching their existing kernel.
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NOTE: Packages marked with "Remerge" as "YES" require a re-merge
even though Portage does not indicate a newer version!
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14 affected packages on all of their supported architectures.
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Description
==========
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.
Impact
=====
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.
Workaround
=========
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.
Resolution
=========
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.
Availability
===========
This GLSA and any updates to it are available for viewing at
the Gentoo Security Website:
http://security.gentoo.org/glsa/glsa-200407-12.xml
Concerns?
========
Security is a primary focus of Gentoo Linux and ensuring the
confidentiality and security of our users machines is of utmost
importance to us. Any security concerns should be addressed to
security@gentoo.org or alternatively, you may file a bug at
http://bugs.gentoo.org.
License
======
Copyright 2004 Gentoo Foundation, Inc; referenced text
belongs to its owner(s).
The contents of this document are licensed under the
Creative Commons - Attribution / Share Alike license.
http://creativecommons.org/licenses/by-sa/1.0
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