Title: Linux 2.4 Kernel MAC Module Filtering Bypassing Vulnerability
Severity: HIGH
Description:
The Linux Kernel is the core of all Linux-based operating systems. It is maintained by public domain, and steered by Linus Torvalds.
A problem in the Netfilter functions of the Linux Kernel could allow a remote user intended access to sensitive systems. The problem is due to the insufficient checking of fragmented packets.
Netfilter, the Linux Kernel firewall package, offers new functionality that allows the filtration of TCP/IP packets on the basis of Media Access Control (MAC) addresses. This can be used to restrict systems from accessing certain resources on the basis of a semi-permanent identification means (MAC addresses can be changed or aliased in the Linux Kernel).
When a system creates small packets, or fragments of packets, to communicate with another system that has restricted communication on the basis of MAC address, it is possible to bypass filtering. The filter does not acknowledge the MAC entry in the packet headers.
This could allow a system on a local segment of network to gain unintended access to a system by setting a much lower MRU than the rest of the network. This attack will not work across routers and switches, as MAC addressing is a layer-two protocol.
Affected Products:
- Caldera OpenLinux Server 3.1.0
- Caldera OpenLinux Workstation 3.1.0
- Linux kernel 2.4.0
- Linux kernel 2.4.1
- Linux kernel 2.4.10
- Linux kernel 2.4.11
- Linux kernel 2.4.2
- Linux kernel 2.4.3
- Linux kernel 2.4.4
- Linux kernel 2.4.5
- Linux kernel 2.4.6
- Linux kernel 2.4.7
- Linux kernel 2.4.8
- Linux kernel 2.4.9
- MandrakeSoft Linux Mandrake 8.0.0
- MandrakeSoft Linux Mandrake 8.0.0 ppc
- MandrakeSoft Linux Mandrake 8.1.0
- MandrakeSoft Linux Mandrake 8.2.0
- RedHat Enterprise Linux AS 2.1
- RedHat Enterprise Linux AS 2.1 IA64
- RedHat Enterprise Linux ES 2.1
- RedHat Enterprise Linux ES 2.1 IA64
- RedHat Enterprise Linux WS 2.1
- RedHat Enterprise Linux WS 2.1 IA64
- RedHat Linux 7.1.0 alpha
- RedHat Linux 7.1.0 i386
- RedHat Linux 7.1.0 ia64
- RedHat Linux 7.2.0
- RedHat Linux 7.2.0 alpha
- RedHat Linux 7.2.0 i386
- RedHat Linux 7.2.0 ia64
- S.u.S.E. Linux 7.1.0
- S.u.S.E. Linux 7.2.0
- S.u.S.E. Linux 7.3.0
- Slackware Linux 8.0.0
- Sun Linux 5.0.0
- Sun Linux 5.0.3
- Sun Linux 5.0.5
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