Dynamix UM-A User Manual page 105

Reassembly Attack checking: Reassembly Attack is a type of DoS attack that
exploits the weakness of the IP protocol reassembly process. As discussed earlier in
this user guide, packets undergo fragmentation when they exceed a certain
maximum size. Certain criteria define the packet fragmentation process so that
packets can be reassembled properly. In Reassembly Attack, the subpackets have
malformed criteria (fragment offset), which can easily cause a system to crash,
freeze, or reboot. Enable this option to check for and filter out Reassembly Attack
packets.
Advanced Protection:
SYN Flooding checking: SYN Flooding is a type of DoS attack that is
accomplished by not sending the final acknowledgement to the receiving server's
SYN-ACK (SYNchronize-ACKnowledge) in the final part of the handshake
process. This causes the serve to keep signaling until it is timed out. When a flood
(many) of these attacks are sent simultaneously, the server will probably overload
and crash. Enable SYN Flooding checking to filter out possible SYN flood packets.
ICMP Redirection checking: Also known as an ICMP storm attack or smurf
attack, ICMP Redirection is another form of DoS. This attack is performed by
sending ICMP echo requests to a broadcast network node. The return IP address is
spoofed and replaced by the victim's own address, causing it to send the request
back to itself. This causes the broadcast address to send it out to all the network
nodes in the broadcast area (usually the entire LAN). In turn, all those recipients
resend it back to the broadcast. The process repeats itself, gaining more amplitude
through each iteration and eventually causing a traffic overload and crashing the
network. Enable ICMP Redirection checking to filter out packets containing the
threat.
Source Routing checking: Source routing gives the sender of a packet the ability
to determine the exact route that an IP packet takes to get to the destination.
However, source routing can be used for malicious reasons. Using a source routed
packet, the sender could find out important information about nodes in a network,
making it easy to exploit any weakness. Enabling Source Routing checking will
cause the firewall to filter out any packet with Source Routing properties.
WinNuke Attack checking: WinNuke exploits a large networking bug found in
Windows 95 and NT. WinNuke sends erroneous OOB (Out-of-Band) data that
Windows is unable to process, causing the target computer to crash. Enable this if
you are running an early (95 or NT) version of Windows that is vulnerable to this
attack.
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