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

This script is Copyright (C) 2004-2014 Tenable Network Security, Inc.


Synopsis :

The remote Gentoo host is missing one or more security-related
patches.

Description :

The remote host is affected by the vulnerability described in GLSA-200407-12
(Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling)

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.

See also :

http://www.gentoo.org/security/en/glsa/glsa-200407-12.xml

Solution :

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.

Risk factor :

Medium / CVSS Base Score : 5.0
(CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:P)

Family: Gentoo Local Security Checks

Nessus Plugin ID: 14545 (gentoo_GLSA-200407-12.nasl)

Bugtraq ID:

CVE ID: CVE-2004-0626