Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling
1.
Gentoo Linux Security Advisory
Version Information
| Advisory Reference |
GLSA 200407-12 / Kernel |
| Release Date |
July 14, 2004 |
| Latest Revision |
October 10, 2004: 02 |
| Impact |
high |
| Exploitable |
remote |
| Package |
Vulnerable versions |
Unaffected versions |
Architecture(s) |
| sys-kernel/aa-sources |
<
2.6.5-r5 |
>=
2.6.5-r5,
<
2.6*
|
All supported architectures
|
| sys-kernel/ck-sources |
<
2.6.7-r2 |
>=
2.6.7-r2,
<
2.6*
|
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,
<
2.6 |
All supported architectures
|
| sys-kernel/mm-sources |
<
2.6.7-r4 |
>=
2.6.7-r4,
<
2.6*
|
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,
<
2.6 |
All supported architectures
|
| sys-kernel/usermode-sources |
<
2.6.6-r2 |
>=
2.6.6-r2,
<
2.6 |
All supported architectures
|
| sys-kernel/win4lin-sources |
<
2.6.7-r1 |
>=
2.6.7-r1,
<
2.6 |
All supported architectures
|
| sys-kernel/xbox-sources |
<
2.6.7-r1 |
>=
2.6.7-r1,
<
2.6 |
All supported architectures
|
Warning: *: Needs to be manually updated
|
Related bugreports:
#55694
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.
2.
Impact Information
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.
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.
3.
Resolution Information
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:
Code Listing 3.1: Resolution |
# 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.
|
4.
References
|
