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Don’t click on that! Kevin Hill.  Spam: Unwanted commercial email ◦ Advertising ◦ Comes from people wanting to sell you stuff. ◦ Headers may be forged.

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Presentation on theme: "Don’t click on that! Kevin Hill.  Spam: Unwanted commercial email ◦ Advertising ◦ Comes from people wanting to sell you stuff. ◦ Headers may be forged."— Presentation transcript:

1 Don’t click on that! Kevin Hill

2  Spam: Unwanted commercial email ◦ Advertising ◦ Comes from people wanting to sell you stuff. ◦ Headers may be forged to hide actual accounts sending the email.  Phishing: email pretending to be from someone else you trust ◦ Deceptive ◦ Designed to look like legitimate email from a trusted source. ◦ Banks, ISPs, corporate IT departments.

3  We use block lists to block emails from known spam sending servers.  Many sites now using Sender Reputation systems.  Spam reports from Fermilab = bad reputation scores.

4  Look at the “Full Headers”  Why “Full Headers”? ◦ Email has envelope From and To addresses, just like old timey postal mail. ◦ The headers your mail client shows are equivalent to addresses at the top of a physical letter. ◦ All servers add a “Received:” header. Only headers added by local or trusted upstream servers are trustworthy. ◦ Don’t trust those either.

5  Never, ever send usernames and passwords via email.  Don’t enter your username and passwords into a web form/application you don’t recognize/expect to use.  Don’t forward your fnal.gov email to another site and then report messages from it as spam.

6  HTML links have two parts: a display part and a URL  “click here” => http://example.com/nextpage.hmtl http://example.com/nextpage.hmtl  Don’t assume a link that looks like a URL actually links to that URL  “http://www.fnal.gov/computing” => http://www.example.com/hacked_app/scam_ me.php “http://www.fnal.gov/computing http://www.example.com/hacked_app/scam_ me.php

7  URLs can be prefixed with a username/password.  http://www.fnal.gov:computing.email.login@ example.com/hackme.html is a valid URL, but doesn’t go where you might think at first glance. http://www.fnal.gov:computing.email.login@ example.com/hackme.html  Read emails in plain text instead of html when you can.

8  Holding the pointer over a URL should show where its actually linking in the status line.  Latest versions of browser more clearly show if an SSL link is really registered to that domain.  Beware of fake SSL certs! Hard to be 100% sure. Use good judgment.

9  Look at mouse-over’s in your mail client to see where a link is really pointing.  Better to type in URLs then to click on untrustworthy links, but don’t mistype!  Save bookmarks to important pages.  Use bookmarks when you get an email requesting you do something at a particular site.

10  Emails about Fermilab systems will not come from non-fnal.gov addresses.  Real Fermilab web forms/apps will not be hosted on non-fnal.gov websites.  Outsourcing/Cloud based hosting makes things complicated.

11  Messages available at http://home.fnal.gov/~kevinh/SNP/

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