16
By NOP'ing a command in line 2 it instead making the program think it should the result
would
also
become
different
in
Line
4.If
it
in
game
health it
may
cause
the code
to
a
different function, like have it INCREASE your health
when
you are shot as opposed
to
decreasing it.
2.11 Packet Sniffing
Packet
sniffing
is
a
technique
of
monitoring network traffic. It is effective on both
switched
and
non-switched
networks.
In
a
non-switched network environment packet
sniffing
is
an
easy
thing to
do.
This
is
because
network
traffic
is
sent
to
a
hub
which
broadcasts
it
to
everyone.
Switched networks are
completely
different
in
the
way
they
operate.
Switches work by sending traffic to the destination host only. This happens because
switches have CAM tables. These tables store information like MAC addresses, switch
ports, and VLAN information. Before sending
traffic from one host to another on the
same
local area
network, the
host
ARP
cache is first checked. The ARP cache is a table
that
stores
both
Layer
2
(MAC)
addresses
and
Layer
3
(IP)
addresses
of
hosts
on
the
local
network.
If
the
destination host
isn’t
in the
ARP
cache,
the
source
host
sends
a
broadcast ARP request looking for the host. When the host replies, the traffic can be sent
to
it.
The
traffic
goes
from the
source
host
to
the
switch,
and
then
directly
to
the
destination host. This description shows that traffic isn’t broadcast out to every host, but
only to the destination host, therefore it’s harder to sniff traffic.
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