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Home >> Browse Vulnerability Assessment Database >> Gentoo Local Security Checks >> [GLSA-200407-12] Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling


Vulnerability Assessment Details

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

Vulnerability Assessment Summary
Linux Kernel: Remote DoS vulnerability with IPTables TCP Handling

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


A possible hacker 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.

References:
http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2004-0626


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.


Network Security Threat Level: High


Networks Security ID:

Vulnerability Assessment Copyright: (C) 2005 Michel Arboi

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