Security and ProtectionSecurity and Protection

CS 110CS 110

Fall 2005Fall 2005

ReviewReview

AdwareAdware VirusesViruses WormsWorms

ReviewReview

Email Spoofing Email Spoofing • falsified senderfalsified sender

Email Phishing Email Phishing • obfuscate HTML to trick you into obfuscate HTML to trick you into

submitting private info through submitting private info through deceptive web pagesdeceptive web pages

ReviewReview

Openness in desktop computersOpenness in desktop computers• You permit lots of programs to You permit lots of programs to

read/write data to your hard drive and read/write data to your hard drive and memorymemory

• Computer “listens” for packets on many Computer “listens” for packets on many portsports of its internet connection of its internet connection

http, itunes, email, IM, homeDir, …http, itunes, email, IM, homeDir, … Programs that monitor the ports for packets Programs that monitor the ports for packets

are supposed to be failsafeare supposed to be failsafe Flaws are discovered and exploitedFlaws are discovered and exploited

November 8, 2005November 8, 2005

Three image-rendering flaws in the Three image-rendering flaws in the Windows OS could put millions of Windows OS could put millions of Internet-connected users at risk of PC Internet-connected users at risk of PC takeover attacks.takeover attacks.

The flaws could be exploited by any The flaws could be exploited by any software that displays images, software that displays images, including … Outlook, Word, and including … Outlook, Word, and Internet Explorer.Internet Explorer.

http://www.eweek.com/article2/0,1895,1883850,00.asp

November 8, 2005November 8, 2005

The bugs are considered particularly The bugs are considered particularly dangerous because users could be at dangerous because users could be at risk merely by browsing to a risk merely by browsing to a malicious rigged site with rigged malicious rigged site with rigged image files, or by displaying images image files, or by displaying images in the preview pane of an e-mail in the preview pane of an e-mail programprogram

November 8, 2005November 8, 2005

Any program that renders WMF or EMF Any program that renders WMF or EMF images on the affected systems images on the affected systems could be vulnerable to this attack. could be vulnerable to this attack. An attacker who successfully exploits An attacker who successfully exploits this vulnerability can take complete this vulnerability can take complete control of an affected systemcontrol of an affected system

November 8, 2005November 8, 2005

The bulletin also addresses two The bulletin also addresses two separate unchecked buffers in the separate unchecked buffers in the way the OS renders WMF and EMF way the OS renders WMF and EMF images.images.

March 29, 2005March 29, 2005

A similar flaw was detectedA similar flaw was detected The hackers corrupted the banner The hackers corrupted the banner

images of an advertising companyimages of an advertising company 100s of sites used those banners100s of sites used those banners Microsoft took 90 days (?) to release Microsoft took 90 days (?) to release

a “patch” because of the intricate a “patch” because of the intricate nature of Windows and the extensive nature of Windows and the extensive testing requiredtesting required

Today’s NewsToday’s News

Detect severity of earth quake in first Detect severity of earth quake in first 1.5 seconds1.5 seconds

Send immediate warning to San Send immediate warning to San FranciscoFrancisco

Automatically stop trains and shut Automatically stop trains and shut down critical systems to protect down critical systems to protect themthem

Would you trust it?Would you trust it?

OnwardOnward

CookiesCookies Web BugsWeb Bugs More virusesMore viruses

CookiesCookies

Cookies are somewhat controversialCookies are somewhat controversial• Websites can used them for legitimate Websites can used them for legitimate

reasonsreasons• They can be used for the wrong reasonsThey can be used for the wrong reasons• In any case, they are a In any case, they are a fact of lifefact of life of web of web

browsingbrowsing Cookies allow a web-server to:Cookies allow a web-server to:

• Track your visits to the siteTrack your visits to the site• Learn and remember info about youLearn and remember info about you• Store info on your computerStore info on your computer

http://vreport.capaho.com/demo.html

What Is a Cookie?What Is a Cookie? A small piece of information stored by A small piece of information stored by

your web-browser on your PC when your web-browser on your PC when you visit a siteyou visit a site

What’s stored:What’s stored:• A URL related to the site you visitedA URL related to the site you visited• A name/value pair (the information A name/value pair (the information

content)content)• (Optional) An expiration date(Optional) An expiration date

Why is it a “cookie”? Why is it a “cookie”? • An old CS term for a chunk of data used An old CS term for a chunk of data used

obscurelyobscurely

Reminder: Web Browser Reminder: Web Browser and Server Interactionand Server Interaction

User types URL or clicks linkUser types URL or clicks link Browser sends a Browser sends a get-pageget-page request for request for

that URL to web-serverthat URL to web-server Web-server finds HTML file (and Web-server finds HTML file (and

related files)related files) Web-server sends these back to Web-server sends these back to

browserbrowser Browser processes HTML and displays Browser processes HTML and displays

pagepage

Cookies: Web-servers Store Cookies: Web-servers Store Some Info on your PCSome Info on your PC

When sending back a page, When sending back a page, server alsoserver also sendssends a cookiea cookie

Your browser stores it on your PCYour browser stores it on your PC Later, you visit the same siteLater, you visit the same site

• You request a page there You request a page there andand your browser has your browser has earlier stored a cookie matching that URLearlier stored a cookie matching that URL

• Browser sends URL Browser sends URL andand cookie cookie to web-server to web-server• Web-server processes cookieWeb-server processes cookie

May return updated cookies with pageMay return updated cookies with page

Normally browsing the Normally browsing the web is "stateless"web is "stateless"

““Stateless” means “no memory”Stateless” means “no memory”• Request a page from a server; it sends itRequest a page from a server; it sends it• Later request a 2nd page; the server sends itLater request a 2nd page; the server sends it• The webserver doesn't remember anything The webserver doesn't remember anything

connecting these two requestsconnecting these two requests But, cookies preserve “state.” Server can But, cookies preserve “state.” Server can

connect an early visit with a later visit.connect an early visit with a later visit.• How? Cookie stored a numeric ID number for How? Cookie stored a numeric ID number for

youyou FYI, a server FYI, a server doesdoes “log” requests “log” requests

• what page, what IP address, when, browserwhat page, what IP address, when, browser• But this can’t identify you uniquelyBut this can’t identify you uniquely

Cookies Can Be BeneficialCookies Can Be Beneficial Shopping CartsShopping Carts

• Server creates a cart, stored on the serverServer creates a cart, stored on the server• You visit other pages, but a cookie lets the You visit other pages, but a cookie lets the

server know you’re the person who created server know you’re the person who created that cartthat cart

Other personalizationOther personalization• ““Welcome back, Jane Doe!”Welcome back, Jane Doe!”• ““Items you viewed recently are…”Items you viewed recently are…”

Recognizing legitimate users for a siteRecognizing legitimate users for a site• Register and log-in, but then a cookie means Register and log-in, but then a cookie means

you don’t have to log-in every timeyou don’t have to log-in every time

The Darker Side of CookiesThe Darker Side of Cookies

We assume anonymity on the web, We assume anonymity on the web, right?right?

Do you want someone knowing what Do you want someone knowing what pages you’ve visited?pages you’ve visited?• Cookies allow a website to track what you Cookies allow a website to track what you

visited on that sitevisited on that site• Are they keeping this private? Selling it?Are they keeping this private? Selling it?

Do you even know they’re tracking your Do you even know they’re tracking your visits?visits?

• What are your rights here?What are your rights here?

The Darker Side of Cookies (2)The Darker Side of Cookies (2)

Personalized ads (e.g. the company Personalized ads (e.g. the company DoubleClick)DoubleClick)• Advertising image on a page is really on Advertising image on a page is really on

another serveranother server• You click on the image on the ad-serverYou click on the image on the ad-server• It builds up a profile about you over timeIt builds up a profile about you over time• Deliver ads you want to seeDeliver ads you want to see

When used for authorization, are they When used for authorization, are they secure?secure?

You Have ControlYou Have Control

You can configure your browser to You can configure your browser to handle cookies as you wanthandle cookies as you want

Cookies: Should You Worry?Cookies: Should You Worry? Hard to say…Hard to say…

• Some are quite useful. They allow e-Some are quite useful. They allow e-commerce!commerce!

• Some are sneakySome are sneaky Some anti-spyware tools remove Some anti-spyware tools remove

undesirable cookies (some remove undesirable cookies (some remove harmless ones)harmless ones)

Where We Are in the LectureWhere We Are in the Lecture

Email issuesEmail issues• attachments and email-spoofingattachments and email-spoofing• phishingphishing

CookiesCookies Web-bugsWeb-bugs Viruses in emailViruses in email Spyware (including browser hijacks)Spyware (including browser hijacks)

What’s a Web Bug?What’s a Web Bug? We know visiting a URL “announces” your We know visiting a URL “announces” your

presencepresence If the web page you visit has images, If the web page you visit has images,

those images can be references to other those images can be references to other web pages:web pages:

Consider foobar.html at Consider foobar.html at www.foo.comwww.foo.com• foobar.html includesfoobar.html includes• <img src=“http://www.virginia.edu/rotunda.gif><img src=“http://www.virginia.edu/rotunda.gif>

What’s a web bugWhat’s a web bug

Something that makes your machine Something that makes your machine execute a execute a get-pageget-page request for a site request for a site you don’t expectyou don’t expect• The server there logs delivery of that The server there logs delivery of that

imageimage May be invisible (hard to see a 1x1 May be invisible (hard to see a 1x1

pixel … VIEW SOURCE)pixel … VIEW SOURCE) Sometimes known as a "clear GIFs", Sometimes known as a "clear GIFs",

"1-by-1 GIFs" or "invisible GIFs“"1-by-1 GIFs" or "invisible GIFs“

http://www.eff.org/Privacy/Marketing/web_bug.htmlhttp://www.eff.org/Privacy/Marketing/web_bug.html

Examples (in HTML)Examples (in HTML)

<img <img src="http://ad.doubleclick.net/ad/pixel.qusrc="http://ad.doubleclick.net/ad/pixel.quicken/NEW" width=1 height=1 icken/NEW" width=1 height=1 border=0>border=0>

<img width='1' height='1' <img width='1' height='1' src="http://www.m0.net/m/logopen02.assrc="http://www.m0.net/m/logopen02.aspp? ? vid=3&catid=370153037&email=SMITHSvid=3&catid=370153037&email=SMITHS%40tiac.net%40tiac.net" alt=" "> " alt=" ">

What Info Can Be Gathered?What Info Can Be Gathered?

Again, the server where the bug lives will Again, the server where the bug lives will log:log:• The IP address of your computer The IP address of your computer • The URL of the page that the Web Bug is located The URL of the page that the Web Bug is located

onon• The URL of the Web Bug imageThe URL of the Web Bug image• The time the Web Bug was viewedThe time the Web Bug was viewed• The type of browser that fetched the Web Bug The type of browser that fetched the Web Bug

imageimage Also possible: Info from any cookie that's Also possible: Info from any cookie that's

on your machineon your machine

Web Bugs on a Web PageWeb Bugs on a Web Page

Using personal info in a cookie, ad Using personal info in a cookie, ad companies can track what pages you companies can track what pages you view over timeview over time• Stores this info in a databaseStores this info in a database• Later used to target specific banners ads Later used to target specific banners ads

for youfor you

How many people view a websiteHow many people view a website

Web Bugs Used in an EmailWeb Bugs Used in an Email

Tells if and when a message was readTells if and when a message was read Links email address with the IP address of Links email address with the IP address of

machine you read mail onmachine you read mail on Within an organization, can tell how often Within an organization, can tell how often

a message is forwarded and reada message is forwarded and read In spam:In spam:

• How many users have seen the spam messageHow many users have seen the spam message• Allows spammers to detect valid email Allows spammers to detect valid email

addressesaddresses

Web Bugs: Legal, Ethical?Web Bugs: Legal, Ethical?

Controversial! Attempt to monitor Controversial! Attempt to monitor you without your knowledgeyou without your knowledge

Legal? Not clearly illegalLegal? Not clearly illegal They They areare used on the websites of used on the websites of

legitimate companieslegitimate companies Privacy policies for websites Privacy policies for websites

generally don't mention thesegenerally don't mention these

Web Bugs: What can you do?Web Bugs: What can you do?

You can't easily identify web bugsYou can't easily identify web bugs New email clients (e.g. Mozilla New email clients (e.g. Mozilla

Thunderbird) do not display images in Thunderbird) do not display images in email that are links to files on external email that are links to files on external sites (see next slide)sites (see next slide)• (Images embedded as part of email message (Images embedded as part of email message

are OK)are OK)• You can click "Show Images" buttonYou can click "Show Images" button• Also nice not to see some images in spamAlso nice not to see some images in spam

Helps to disable and delete cookiesHelps to disable and delete cookies

An Email Client Blocks Remote ImagesAn Email Client Blocks Remote Images

AnonymityAnonymity

Are you really anonymous surfing the Are you really anonymous surfing the web?web?• Someone (corporations and whoever buys their Someone (corporations and whoever buys their

data) is collecting info on your browsingdata) is collecting info on your browsing Do we want:Do we want:

• Tools to “protect” us from this?Tools to “protect” us from this?• Laws against it?Laws against it?• Laws that disclose it’s being done and how the Laws that disclose it’s being done and how the

info is used?info is used?• Users to be aware it’s going on? (Yes!)Users to be aware it’s going on? (Yes!)

Where We Are in the LectureWhere We Are in the Lecture

Email issuesEmail issues• attachments and email-spoofingattachments and email-spoofing• phishingphishing

CookiesCookies Web-bugsWeb-bugs Viruses in emailViruses in email Spyware (including browser hijacks)Spyware (including browser hijacks)

Anatomy of a virusAnatomy of a virus

How you can be infectedHow you can be infected• By just reading email when…By just reading email when…

you do not keep your software updated!you do not keep your software updated!

Links in E-mailLinks in E-mail

The “data format” of Web pages is HTMLThe “data format” of Web pages is HTML• Controls the formatting of a Web pageControls the formatting of a Web page• Also supports hyperlinks to other pagesAlso supports hyperlinks to other pages• It’s nice when e-mail has this format, right?It’s nice when e-mail has this format, right?

A danger:A danger:• Some links can cause a program to run.Some links can cause a program to run.• Some download files that run on your system.Some download files that run on your system.

An attacker can disguise a link so it looks An attacker can disguise a link so it looks harmless (but…)harmless (but…)

Virus through a Link in an Virus through a Link in an EmailEmail

Link Link seemsseems to be to CS dept. (www.cs.virginia.edu) to be to CS dept. (www.cs.virginia.edu) That’s the That’s the texttext of the link of the link

• It links to someplace elseIt links to someplace else• An attachment that is disguised so it doesn’t appearAn attachment that is disguised so it doesn’t appear• The small box is the only clueThe small box is the only clue

How Can This Virus Get How Can This Virus Get Triggered?Triggered?

Click the link, and it tries to display the Click the link, and it tries to display the hidden attachmenthidden attachment• Only in someOnly in some email clients, i.e. older email clients, i.e. older

versions of Outlookversions of Outlook• Note: This vulnerability has been known!Note: This vulnerability has been known!

Patches available through Windows Update!Patches available through Windows Update! Click and… Congratulations!Click and… Congratulations!

• You’re now infected with a version of the You’re now infected with a version of the Netsky virus!Netsky virus!

What’s Netsky Do?What’s Netsky Do? A mass-mailing worm A mass-mailing worm

• Harvests email addresses from files on your PCHarvests email addresses from files on your PC• Comes with its own mail-server componentComes with its own mail-server component• Now a server on your machine that uses the SMTP Now a server on your machine that uses the SMTP

protocol to send copies of the virus directly to protocol to send copies of the virus directly to others!others!

You’re infected You’re infected andand contagious contagious• You’ll be very popular with your friends and other You’ll be very popular with your friends and other

email contacts!email contacts!• But they should have been running antivirus But they should have been running antivirus

software, and should have kept their systems software, and should have kept their systems updated.updated.

• (Like you should have been.)(Like you should have been.)

LessonsLessons

Use Windows Update to keep your system Use Windows Update to keep your system updatedupdated• AKA keep it “patched”AKA keep it “patched”

You might consider using software that is You might consider using software that is not the major target of virus writersnot the major target of virus writers• Other operating systems (Mac OS, Linux)Other operating systems (Mac OS, Linux)• Other email clients, other browsersOther email clients, other browsers

And And definitelydefinitely install and run anti-virus install and run anti-virus software (next slide)software (next slide)

SolutionsSolutions Antivirus SoftwareAntivirus Software

• Can scan your system: find and remove Can scan your system: find and remove problemsproblems

• Usually only viruses. Sometimes spyware too.Usually only viruses. Sometimes spyware too.• Also, most have Also, most have real-timereal-time protection protection

Checks e-mail as your read it, as you send itChecks e-mail as your read it, as you send it Checks files as you download themChecks files as you download them

• Note: Free for UVa users (see later slide)Note: Free for UVa users (see later slide) Important: run “update” on these to get Important: run “update” on these to get

updated virus definitionsupdated virus definitions

Where We Are in the LectureWhere We Are in the Lecture

Email issuesEmail issues• attachments and email-spoofingattachments and email-spoofing• phishingphishing

CookiesCookies Web-bugsWeb-bugs Viruses in emailViruses in email Spyware (including Spyware (including

browser hijacks)browser hijacks)

Browser HijackBrowser Hijack

An extremely nasty adwareAn extremely nasty adware Resets homepage to a particular siteResets homepage to a particular site

• Ads, porn – something you don’t wantAds, porn – something you don’t want• Any change you make doesn’t affect itAny change you make doesn’t affect it

Software running on your machineSoftware running on your machine• Does the usual adware/spyware stuffDoes the usual adware/spyware stuff• Also changes your browser settingsAlso changes your browser settings• Runs when system starts – changes the Runs when system starts – changes the

settings backsettings back

Spyware is a Common Spyware is a Common Problem!Problem!

Recall earlier study of users:Recall earlier study of users:

80% had spyware on their PCs80% had spyware on their PCs

(What about you?)(What about you?)

SolutionsSolutions Anti-spyware softwareAnti-spyware software

• Scans your system, removes problemsScans your system, removes problems• Some have real-time protection, most don’t.Some have real-time protection, most don’t.

Important (again): run “update” on these Important (again): run “update” on these to get most recent spyware definitionsto get most recent spyware definitions

Another option: Security Suites ($60-$70)Another option: Security Suites ($60-$70)• Include antivirus, maybe anti-spyware softwareInclude antivirus, maybe anti-spyware software• Also includes a firewallAlso includes a firewall• May include spam filtering, parental controlMay include spam filtering, parental control

Getting Software at UVaGetting Software at UVa

ITC Downloads: ITC Downloads: http://www.itc.virginia.eduhttp://www.itc.virginia.edu• Norton AntivirusNorton Antivirus• SpySweeper (up to 3 machines)SpySweeper (up to 3 machines)• Free for UVa users!Free for UVa users!

This is a This is a wonderfulwonderful deal for students and deal for students and staff.staff.

Don’t be foolish! Please go install these! Don’t be foolish! Please go install these! • And keep things updated. Practice good habits.And keep things updated. Practice good habits.

Anti-Virus SW For Your Anti-Virus SW For Your Non-UVa FriendsNon-UVa Friends

Free anti-virus software through websitesFree anti-virus software through websites• http://http://housecall.trendmicro.comhousecall.trendmicro.com//• http://http://www.pandasoftware.com/activescanwww.pandasoftware.com/activescan//• These two reviewed recommended by reliable These two reviewed recommended by reliable

magazinesmagazines These run their program on your PC from These run their program on your PC from

their websitetheir website• Scans your system and identifies problemScans your system and identifies problem

Does not include real-time protectionDoes not include real-time protection

Anti-Spyware SW For Your Anti-Spyware SW For Your Non-UVa FriendsNon-UVa Friends

Good Good freefree utilities to find and remove utilities to find and remove spywarespyware• Lavasoft Adware: Lavasoft Adware: http://http://www.lavasoftusa.comwww.lavasoftusa.com//• Spybot Search & Destroy:Spybot Search & Destroy:

http://http://www.spybot.infowww.spybot.info Download, install, and run periodicallyDownload, install, and run periodically Updates:Updates:

• Must get updates of definitions for Antivirus Must get updates of definitions for Antivirus and spyware removal toolsand spyware removal tools

• Often free: use update facility in the toolOften free: use update facility in the tool

SpySweeper in ActionSpySweeper in Action

Scanning Your PCScanning Your PC

Removing What It FoundRemoving What It Found

The ResultsThe Results

Everything That Looks Like Spyware Everything That Looks Like Spyware Removal Is Removal Is NotNot Spyware Removal Spyware Removal

•Email arrives with animated GIF file.

• Click on OK – you’re really clicking on the web-link associated with that image. Uh oh.

Final WordsFinal Words Cookies and web bugs raise privacy Cookies and web bugs raise privacy

issuesissues Malware: it’s a nasty world out there!Malware: it’s a nasty world out there!

Protect yourself with:Protect yourself with:• UnderstandingUnderstanding• Tools (anti-virus SW, anti-spyware SW)Tools (anti-virus SW, anti-spyware SW)

Practice good habits:Practice good habits:• Be suspicious and cautiousBe suspicious and cautious• Install, run, and update toolsInstall, run, and update tools• Keep your operating system updatedKeep your operating system updated