Network Security
Demo:
Email Messages
9 An email message can be instantly forwarded around the globe, even if accidentally.
– Do not write anything in a message that you will later regret!
– Read over the message before you send it!
9 Email messages can carry dangerous attachments.
– Do not open any file attached to a message unless you are absolutely certain of the sender of the message and the safety of the attachment.
Viruses & Trojan Horses
9 Viruses and trojan horses are programs designed to
replicate themselves as they pass from computer to computer - and usually do harm!
9 They are usually passed by a user opening an infected attachment. Don’t do that!
9 You should have a good antivirus program on your home computer and keep it up-to-date on the latest viruses.
Viruses & Trojan Horses
(cont’d)
9
Real viruses are reported at a number of sites:
–
Symantec.com – Viruses & Risks
http://www.symantec.com
–
McAfee.com – Threat Center
Hoax Viruses
9
Hoax virus warnings are frequently sent by email,
and unknowing users forward them to all of their
friends. Two known factors make a successful
virus hoax:
–
(1) technical sounding language, and
–
(2) credibility by association, in that the
warning appears to come from a knowledgeable
person.
Internet Hoaxes
9
Hoax viruses (and other myths and urban legends)
are reported at several sites:
–
Urban Legends and Folklore
-http://urbanlegends.about.com/
–
Symantec Antivirus Research Center
-http://www.symantec.com/avcenter/hoax.html
–
Truth or Fiction
-http://www.truthorfiction.com
Chain Email
9 Chain email letters are related to hoax virus warnings in
that they often spread false information, and they ask to be forwarded to “all of your friends.”
9 You should NOT forward chain letters.
9 Forwarding chain letters of any type is a violation of the acceptable use policy at UH (and at most, if not all,
Internet Service Providers).
Web Bugs
9 A web bug is an object – usually an invisible image – that is embedded in a web page or e-mail and allows checking that a user has viewed the page or e-mail.
9 If in an email, when the image is loaded, the request to the remote server to get the images tells the server you have read the message…the email address is a good one.
=>Disable automatic image display in email
9 If in a web page, the image is usually loaded from an
advertiser’s server, not the server from which the page was loaded, so that the advertiser can track your browsing.
Block remote images in email
Block remote images in browser
Cookies
9 An HTTP cookie is text sent by a server to a web browser and then sent back unchanged by the browser each time it accesses that server.
9 During a session, cookies are used for maintaining specific information about users, such as the contents of electronic shopping carts. (good!)
9 Third-party cookies: If an advertising image is retrieved
from a remote (third party) server other than that of the original web page, that remote server can maintain a
cookie – a tracking cookie – that follows your tracks between web sites. (not so good)
Block third-party cookies in browser
Phishing
9
Phishing attempts to fraudulently acquire
sensitive information, such as passwords and
credit card details, by masquerading as a
trustworthy person or business in an email or
instant message.
9
The user is told to “verify your account” and is
provided a link to click on for doing so.
9
But the text containing the link does not match the
link itself, which actually directs the user to an
Phishing
(cont’d)
9 For example, the text might look like this:
https://service.capitalone.com/...
9 but the actual link behind the text might be:
http://www.capitalone0.go.ro/onlinebanking.capitalone. com/CAPITALONE/index.html
=>Don’t click on that link!
apparent link actual link
Spam
9
Spamming is the abuse of electronic messaging
systems to send unsolicited, bulk messages.
9
Email is the most recognized form, but spam also
targets instant messaging, blogs, chat rooms, etc.
9
Although all types of unwanted messages – chain
email, viruses, phishing attempts – could be
considered spam, the term is most commonly
attributed to unsolicited advertising.
9
Your most important defenses against spam are
Security Tips
9 Make your passwords hard to guess, change frequently.
9 Disable remote images in email and browser.
9 Disable third-party cookies in your browser.
9 Use a firewall.
9 Use anti-virus software. (McAfee)
9 Use adware and spyware detectors. (Ad-Aware, Spybot)
9 Keep all software patched up-to-date. (Windows Update)
9 Don’t open unexpected attachments.
9 Don’t click on phishing links.
9 Use an email spam filter.
9 Protect your email address.
9
