Spying and security on the Internet Some tricks to know

–Are we spied on on the internet? –What kind of information on my computer can be found by other people? –Why is that possible? –How it works ?

Summary 1/Am I spied on ? 2/IP Audit 3/Cookies 4/Cache memory

AM I SPIED ON WHILE SURFING ? THAT IS THE QUESTION…

-YES YOU ARE !!! -No, I can’t believe it !!

-You want a demo baby ? -Yes, I do…

Is that enough ? Or do you want more ?

Give me your IP and I’ll tell you who you are…

One more time with more pieces of information… rch=Searchhttp:// rch=Search

How it works ? TCP/IP: virtual networks Need connection and identification Requests have pieces of information: of webpage + –Information on your computer : REMOTE_HOST = REMOTE_ADDR = HTTP_USER_AGENT = Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1) HTTP_REFERER = -a CGI (Common Gateway Interface) script analyse this data: REMOTE_HOST et REMOTE_ADDR gives your DNS and IP -HTTP_USER_AGENT gives pieces of information of your browser -HTTP_REFERER gives protocols, access-ways, pages, images etc.

IP audits Client/servers/requests The server needs your IP to send you what you asked for is find thanks to DNS server DNS=Domain The paquets contain: of the computer which sent the packet, of the computer to which it is sent.

Nothing hampers the computer to create a file with your DNS, the date, the hour and the file. You are not « aware » of this recording It is called « audit-files » Concerning the CNIL, they have a CGI script that gathers and analyses the audit- file of their servers

What is it ? A file on your disk Content : Data you have once given (voluntarily or not) Ex : a login, the number of accesses to the site, your favourite beer…

How does it work ? An instruction in the page : Set-Cookie : Name=value; expires=date; path=chemin, domain=nom_domain; secure Information re-sent to the server each time you visit the page Can I block them ? Yes… see the options of your browser

Advantages to save some useful data (Ex.: login, preferences…) transparent use Disadvantages On your pc only  s.o else’s cookies… / Lost data Content not readable Negative use : linked to your name / address  advertising,…

What is it ? Files saved - on your pc - on a proxy Content : Files which are downloaded when you look at a page (ex: images…)

How does it work ? Files loaded are saved in the cache memory When needed, the file is loaded from - the cache memory, if it is present - otherwise: downloaded  faster Can I block it ? - On your pc : Yes… see the options of your browser - On the proxy : No… unless you don”t use one

Advantage faster Disadvantage one can see what pages you visited

Conclusion There are plenty of ways to find data on people on the internet. There are ways to hamper them, but nobody can really surf without being able to be found…