By Leo Notenboom
I’ve heard that instant messages through AOL/Yahoo/MSN can be read by hackers that “sniff” the messages leaving my network. Is this true?
It’s actually true for all the data that comes and goes on your internet connection: web pages, emails, instant messaging conversations and more.
Most of the time it simply doesn’t matter. Honest.
On the other hand, there are definitely times and situations when you really do need to be careful.
Data traveling on a network such as the internet can be seen by many other
machines. Local machines connected via a hub, for example, all see the data
being sent to and from all the other machines connected to the same hub. As the
data travels across the internet, it actually travels across many devices each
of which can “see” the data.
The good news is that’s actually pretty hard to find data transmitted to and
from a specific machine unless you’re on the same network segment. For
example, if you’re connected to the internet via DSL, other machines sharing
that DSL connection might watch your traffic, but random machines out on the
internet would have an extremely difficult time tracking it down.
It’s not something I worry about much at home.
However, there are scenarios that you should be very aware of.
you’re home to access sensitive sites like online banking or others.”
Wireless access points operate much like a hub. Any
wireless adapter within range can see all of the network
traffic in the area. Visited any open (meaning not WPA-encrypted) wireless
hotspots lately? Anyone in the coffee shop or library, or even just outside on
the street or a nearby building, could be sniffing your traffic.
Hotel or other third-party provided internet connections
are also vulnerable, since you have no idea what, or who, is sharing or
watching your connection. It’s possible that you’re on a hub, and the room next
door or down the hall could be watching your traffic, or it’s possible that the
hotel staff themselves are tapped into the internet traffic to and from all the
Landlord-provided internet connections, or those provided
by or shared with a roommate or housemate fall into the same category: whomever
set it up could very easily be watching the internet traffic going to and from
the connection(s) that they provide you.
Your connection at work can also easily be monitored by
your employer. In fact, the only difference between your employer and a hotel
or landlord provided connection is that in most places the employer snooping on
your use of their connection is legal, whereas the others typically are
[This post is excerpted with Leo’s permission from his Ask Leo blog.]
Leo Notenboom has been involved in the tech industry for nearly 30 years. After retiring from an 18 year career as a Microsoft Software Engineer Leo went on to create Ask Leo!, a free web site where he answers real questions from ordinary computer users.
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