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terminology.html
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<!DOCTYPE html>
<html lang="en"><head>
<script src="quarto_files/clipboard/clipboard.min.js"></script>
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<link href="quarto_files/quarto-html/quarto-syntax-highlighting-dark.css" rel="stylesheet" id="quarto-text-highlighting-styles"><meta charset="utf-8">
<meta name="generator" content="quarto-1.5.56">
<title>Terminology</title>
<meta name="apple-mobile-web-app-capable" content="yes">
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</head>
<body class="quarto-dark">
<div class="reveal">
<div class="slides">
<section id="title-slide" class="quarto-title-block center">
<h1 class="title">CS 3710</h1>
<h2 class="subtitle">Introduction to Cybersecurity</h2>
<p class="titlep"> </p>
<div class="titlesmall"><p>
<a href="http://www.cs.virginia.edu/~asb">Aaron Bloomfield</a> ([email protected])<br>
<a href="http://github.com/aaronbloomfield/ccc">@github</a> | <a href="index.html">↑</a> | <a href="?print-pdf"><img class="print" width="20" src="../slides/images/print-icon.svg" style="top:0px;vertical-align:middle;background-color:transparent"></a>
</p></div>
<p class="titlep"> </p>
<h2 class="subtitle">Terminology</h2>
</section><section id="TOC">
<nav role="doc-toc">
<h2 id="toc-title">Contents</h2>
<ul>
<li><a href="#/terms" id="/toc-terms">Terms</a></li>
<li><a href="#/malware-types" id="/toc-malware-types">Malware Types</a></li>
<li><a href="#/vulnerabilities-exploited" id="/toc-vulnerabilities-exploited">Vulnerabilities Exploited</a></li>
</ul>
</nav>
</section>
<section>
<section id="terms" class="title-slide slide level1 center">
<h1>Terms</h1>
</section>
<section id="vulnerability-vs-exploit" class="slide level2">
<h2>Vulnerability vs exploit</h2>
<ul>
<li>A <em>vulnerability</em> is a weakness (or bug) in the security of a program
<ul>
<li>A lock that is easy to pick</li>
</ul></li>
<li>An <em>exploit</em> is an attack that makes use of some vulnerability
<ul>
<li>A “skeleton key” that can open many types of locks</li>
</ul></li>
</ul>
</section>
<section id="authentication-vs-authorization" class="slide level2">
<h2>Authentication vs authorization</h2>
<ul>
<li><em>Authentication</em> is determining who a user is
<ul>
<li>Signing in through netbadge, for example</li>
</ul></li>
<li><em>Authorization</em> is controlling one’s actions based on who they are
<ul>
<li>Normal users can not delete certain things, for example</li>
</ul></li>
</ul>
</section>
<section id="vector-vs-payload" class="slide level2">
<h2>Vector vs payload</h2>
<ul>
<li>The malware’s <em>vector</em> is the means by which it attacked the host
<ul>
<li>Virus, buffer overflow, worm, back door, etc.</li>
</ul></li>
<li>The malware’s <em>payload</em> is what damage or effects it causes
<ul>
<li>File deletion, infection of other files, mailing spam, etc.</li>
<li>Malware may not have a payload</li>
</ul></li>
</ul>
</section>
<section id="hack" class="slide level2">
<h2>Hack</h2>
<p>From <a href="https://www.dictionary.com/browse/hack?s=t">dictionary.com</a>:</p>
<blockquote>
<p>hack (intransitive verb): to modify (a computer program or electronic device) or write (a program) in a skillful or clever way</p>
</blockquote>
<blockquote>
<p>hack (intransitive verb): to circumvent security and break into (a network, computer, file, etc.), usually with malicious intent</p>
</blockquote>
</section>
<section id="hacker" class="slide level2">
<h2>Hacker</h2>
<p>From <a href="https://www.dictionary.com/browse/hack?s=t">dictionary.com</a>:</p>
<blockquote>
<p>hacker (noun): a person who has a high level of skill in computer technology or programming; a computer expert or enthusiast</p>
</blockquote>
<blockquote>
<p>hacker (noun): a person who circumvents security and breaks into a network, computer, file, etc., usually with malicious intent</p>
</blockquote>
</section>
<section id="hack-and-hacker-in-context" class="slide level2">
<h2>‘Hack’ and ‘hacker’ in context</h2>
<ul>
<li>Good contexts:
<ul>
<li>We have all heard of (or participated in) hack-a-thons</li>
<li>One may hack a program together</li>
<li>“That’s a great hack”</li>
</ul></li>
<li>Bad contexts:
<ul>
<li>Any malware is termed to be created by ‘hackers’</li>
<li>One who hacks into a secure system to do something malicious</li>
</ul></li>
</ul>
<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
</section></section>
<section>
<section id="malware-types" class="title-slide slide level1 center">
<h1>Malware Types</h1>
</section>
<section id="characteristics-of-malware" class="slide level2">
<h2>Characteristics of malware</h2>
<ul>
<li>Self-replicating: does it reproduce by itself?</li>
<li>Population growth: how does the infected population increase?
<ul>
<li>Zero if it is not self-replicating</li>
<li>But self replicating can have either a zero or positive population growth</li>
</ul></li>
<li>Parasitic: does it need another executable in order to exist?</li>
</ul>
</section>
<section id="logic-bomb" class="slide level2">
<h2>Logic bomb</h2>
<div class="right-float-img img-size-800">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/9/95/Bomb_icon.svg/350px-Bomb_icon.svg.png"></p>
</div>
<ul>
<li>Self-replicating: no</li>
<li>Population growth: zero</li>
<li>Parasitic: possibly </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>Has a <em>payload</em>, which is an action to perform
<ul>
<li>Delete files, etc. – usually a malicious effect</li>
</ul></li>
<li>Has a <em>trigger</em>, which is a Boolean condition as to when to execute
<ul>
<li>On a given date, when somebody performs some action, etc.</li>
</ul></li>
</ul>
</section>
<section id="trojan-horse" class="slide level2">
<h2>Trojan Horse</h2>
<div class="right-float-img img-size-600">
<p><img data-src="https://s-media-cache-ak0.pinimg.com/originals/98/31/91/983191ca276eb1227fd2f85960215b8c.jpg"></p>
</div>
<ul>
<li>Self-replicating: no</li>
<li>Population growth: zero</li>
<li>Parasitic: yes </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A program that looks like a valid program, but has a malicious purpose
<ul>
<li>Stealing passwords, deleting files, etc.</li>
</ul></li>
</ul>
</section>
<section id="back-door" class="slide level2">
<h2>Back door</h2>
<div class="right-float-img img-size-600">
<p><img data-src="http://img11.deviantart.net/8549/i/2012/129/b/b/door_ajar_by_layall-d4z3odw.jpg"></p>
</div>
<ul>
<li>Self-replicating: no</li>
<li>Population growth: zero</li>
<li>Parasitic: possibly </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>Any mechanism that allows bypassing of the normal security checks
<ul>
<li>If you are logging in from this IP address, or enter a specific username, don’t ask for a password</li>
</ul></li>
</ul>
</section>
<section id="virus" class="slide level2">
<h2>Virus</h2>
<div class="right-float-img img-size-400">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/9/94/Coronavirus._SARS-CoV-2.png/768px-Coronavirus._SARS-CoV-2.png"></p>
</div>
<ul>
<li>Self-replicating: yes</li>
<li>Population growth: positive</li>
<li>Parasitic: yes </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>Code that <em>modifies</em> an executable program file and inserts itself into it
<ul>
<li>This self-replication into existing executable code is the defining characteristic of a virus</li>
</ul></li>
<li>Often has a destructive payload</li>
<li>Does not <em>propagate</em> using a network, but infected files can be downloaded or emailed by a network</li>
</ul>
<!-- .slide: class="right-float-img .img-size-400" -->
</section>
<section id="worm" class="slide level2">
<h2>Worm</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/3/30/Regenwurm1.jpg"></p>
</div>
<ul>
<li>Self-replicating: yes</li>
<li>Population growth: positive</li>
<li>Parasitic: no </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A stand-alone program that propagates via a network
<ul>
<li>Typically exploiting a security hole</li>
</ul></li>
<li>It does <em>not</em> modify an existing binary file</li>
</ul>
<!-- .slide: class="right-float-img .img-size-400" -->
</section>
<section id="rabbit" class="slide level2">
<h2>Rabbit</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/3/37/Oryctolagus_cuniculus_Tasmania_2.jpg"></p>
</div>
<ul>
<li>Self-replicating: yes</li>
<li>Population growth: zero</li>
<li>Parasitic: no </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A rapidly reproducing program that consumes all of the available computer resources
<ul>
<li>A fork bomb, for example</li>
</ul></li>
<li>Leaves lots of traces, and doesn’t accomplish much
<ul>
<li>So they aren’t seen very often</li>
</ul></li>
<li>See the <a href="https://en.wikipedia.org/wiki/Fork_bomb">Wikipedia article on “fork bomb”</a> for more</li>
</ul>
</section>
<section id="some-fork-bombs" class="slide level2">
<h2>Some fork bombs</h2>
<p>C++, Python, and Bash shell, respectively:</p>
<div class="sourceCode" id="cb1"><pre class="sourceCode numberSource c number-lines code-with-copy"><code class="sourceCode c"><span id="cb1-1"><a href=""></a><span class="pp">#include </span><span class="im"><stdio.h></span></span>
<span id="cb1-2"><a href=""></a><span class="pp">#include </span><span class="im"><sys/types.h></span></span>
<span id="cb1-3"><a href=""></a><span class="dt">int</span> main<span class="op">()</span> <span class="op">{</span></span>
<span id="cb1-4"><a href=""></a> <span class="cf">while</span><span class="op">(</span><span class="dv">1</span><span class="op">)</span> fork<span class="op">();</span></span>
<span id="cb1-5"><a href=""></a> <span class="cf">return</span> <span class="dv">0</span><span class="op">;</span></span>
<span id="cb1-6"><a href=""></a><span class="op">}</span></span></code><button title="Copy to Clipboard" class="code-copy-button"><i class="bi"></i></button></pre></div>
<p>
</p>
<div class="sourceCode" id="cb2"><pre class="sourceCode numberSource py number-lines code-with-copy"><code class="sourceCode python"><span id="cb2-1"><a href=""></a><span class="im">import</span> os</span>
<span id="cb2-2"><a href=""></a><span class="cf">while</span> <span class="va">True</span>:</span>
<span id="cb2-3"><a href=""></a> os.fork()</span></code><button title="Copy to Clipboard" class="code-copy-button"><i class="bi"></i></button></pre></div>
<p>
</p>
<div class="sourceCode" id="cb3"><pre class="sourceCode numberSource sh number-lines code-with-copy"><code class="sourceCode bash"><span id="cb3-1"><a href=""></a><span class="co">#!/bin/bash</span></span>
<span id="cb3-2"><a href=""></a><span class="fu">:()</span><span class="kw">{</span> <span class="bu">:</span><span class="kw">|</span><span class="bu">:</span><span class="kw">&</span> <span class="kw">};</span><span class="bu">:</span></span></code><button title="Copy to Clipboard" class="code-copy-button"><i class="bi"></i></button></pre></div>
</section>
<section id="spyware" class="slide level2">
<h2>Spyware</h2>
<div class="right-float-img img-size-600">
<p><img data-src="http://4.bp.blogspot.com/-OdK2rCo-g9s/VGRyT8EwP6I/AAAAAAAAAK0/pSxTUYy699g/s1600/spyware.gif"></p>
</div>
<ul>
<li>Self-replicating: no</li>
<li>Population growth: zero</li>
<li>Parasitic: no </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>Software that collects information from a computer and transmits it to somebody else
<ul>
<li>Usernames and passwords, e-mail addresses, financial information, software license keys, etc.</li>
</ul></li>
<li>Viruses and worms can do similar things
<ul>
<li>Spyware is software that doesn’t self replicate</li>
</ul></li>
</ul>
</section>
<section id="adware" class="slide level2">
<h2>Adware</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://cdn.ttgtmedia.com/rms/onlineImages/security-adware.jpg"></p>
</div>
<ul>
<li>Self-replicating: no</li>
<li>Population growth: zero</li>
<li>Parasitic: no </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>Similar to spyware:
<ul>
<li>Gathers information about the user</li>
</ul></li>
<li>But it has differences:
<ul>
<li>It’s more marketing-focused (pops up ads, redirects a browser, etc.)</li>
</ul></li>
</ul>
</section>
<section id="droppers" class="slide level2">
<h2>Droppers</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/3/32/Pipette_tip_over_tube.jpg/548px-Pipette_tip_over_tube.jpg"></p>
</div>
<ul>
<li>Self-replicating: n/a</li>
<li>Population growth: n/a</li>
<li>Parasitic: n/a </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A dropper is a program that deposits malware on a computer</li>
<li>Many viruses or worms contain a dropper for a larger piece of malware</li>
</ul>
</section>
<section id="hybrids" class="slide level2">
<h2>Hybrids</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Chimera_d%27arezzo%2C_fi%2C_04.JPG/640px-Chimera_d%27arezzo%2C_fi%2C_04.JPG"></p>
</div>
<ul>
<li>Self-replicating: n/a</li>
<li>Population growth: n/a</li>
<li>Parasitic: n/a </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A hybrid is a piece of malware that uses multiple techniques discussed here</li>
<li>Hybrid example: Ken Thompson’s UNIX back door
<ul>
<li>Was a Trojan horse, replicated like a virus, created back doors</li>
</ul></li>
<li>Most malware today is hybrids</li>
</ul>
</section>
<section id="zombies" class="slide level2">
<h2>Zombies</h2>
<div class="right-float-img img-size-500">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/a/ad/Zombie_haiti_ill_artlibre_jnl.png/434px-Zombie_haiti_ill_artlibre_jnl.png"></p>
</div>
<ul>
<li>Self-replicating: ?</li>
<li>Population growth: ?</li>
<li>Parasitic: yes (to a computer) </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A zombie is a computer that somebody else can (partially) control
<ul>
<li>Often Windows machines</li>
<li>Can send spam, perform DoS attacks</li>
<li>User is often unaware of the zombie</li>
</ul></li>
<li>A zombie is often a drop of another piece of malware</li>
</ul>
</section>
<section id="botnet" class="slide level2">
<h2>Botnet</h2>
<div class="right-float-img img-size-600">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/c/c0/Botnet2.gif/640px-Botnet2.gif"></p>
</div>
<ul>
<li>Self-replicating: N/A</li>
<li>Population growth: N/A</li>
<li>Parasitic: yes </li>
</ul>
<p class="blankline">
</p>
<ul>
<li>A number of zombie computers controlled by a single source</li>
<li>Example: <a href="https://en.wikipedia.org/wiki/Bredolab_botnet">Bredolab botnet</a>
<ul>
<li>Dismantled in 2010, but controlled 30 <em>million</em> computers at it’s peak</li>
<li>Owner(s) made over $100k per month</li>
</ul></li>
</ul>
</section>
<section id="ransomware" class="slide level2">
<h2>Ransomware</h2>
<div class="right-float-img img-size-600">
<p><img data-src="https://upload.wikimedia.org/wikipedia/commons/thumb/1/12/Ransomware-pic.jpg/640px-Ransomware-pic.jpg"></p>
</div>
<ul>
<li><p>Very common these days</p>
<ul>
<li>It usually is the payload of<br>another attack</li>
</ul></li>
<li><p>It requires one to pay to<br>“release” resources</p></li>
<li><p>Stats (<a href="http://www.businessinsider.com/doj-and-dhs-ransomware-attacks-government-2016-4">source</a>) from an April 2015 report:</p>
<ul>
<li>The DOJ received 7,700 public complains in the last decade, totaling <span class="math inline">\(57.6 million paid
- Generally `\)</span><code>200 to</code>$`10,000 per “episode”</li>
<li>$24 million in 2,500 cases in 2015 alone</li>
</ul></li>
</ul>
<!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
</section></section>
<section>
<section id="vulnerabilities-exploited" class="title-slide slide level1 center">
<h1>Vulnerabilities Exploited</h1>
</section>
<section id="what-vulnerabilities-were-exploited" class="slide level2">
<h2>What Vulnerabilities Were Exploited?</h2>
<ul>
<li>“Vulnerability” often refers only to vulnerable code in an OS or applications
<ul>
<li>E.g. Unguarded buffer overflow in OS command allows attacker to run arbitrary command, gain root access, etc.</li>
<li>Failure to validate user input</li>
<li>Allowing ActiveX controls to be run from scripts</li>
</ul></li>
</ul>
</section>
<section id="what-vulnerabilities-were-exploited-1" class="slide level2">
<h2>What Vulnerabilities Were Exploited?</h2>
<ul>
<li>More generally, a vulnerability is whatever weakness in an overall system that makes it open to attack
<ul>
<li>System administration and configuration flaws</li>
<li>Dangerous user behavior</li>
</ul></li>
</ul>
</section>
<section id="code-vulnerabilities" class="slide level2">
<h2>Code Vulnerabilities</h2>
<ul>
<li>Buffer overflow is the most common
<ul>
<li>Array bounds not usually checked at run time (Why not?)</li>
</ul></li>
<li>What comes <em>after</em> the buffer being overflowed determines what can be attacked
<ul>
<li>Return address can be changed to malicious code</li>
<li>Function pointer can point to malicious code</li>
<li>Output file name for a program can be overwritten with file name desired by attacker</li>
</ul></li>
<li>Buffer overflows are simple to guard against, yet they remain the most common code vulnerability</li>
</ul>
</section>
<section id="buffer-overflow-example" class="slide level2">
<h2>Buffer Overflow Example</h2>
<div class="sourceCode" id="cb4"><pre class="sourceCode numberSource c number-lines code-with-copy"><code class="sourceCode c"><span id="cb4-1"><a href=""></a><span class="dt">void</span> bogus<span class="op">(</span><span class="dt">void</span><span class="op">)</span> <span class="op">{</span></span>
<span id="cb4-2"><a href=""></a> <span class="dt">int</span> i<span class="op">;</span></span>
<span id="cb4-3"><a href=""></a> <span class="dt">char</span> buffer<span class="op">[</span><span class="dv">256</span><span class="op">];</span> <span class="co">// Return address follows!</span></span>
<span id="cb4-4"><a href=""></a></span>
<span id="cb4-5"><a href=""></a> printf<span class="op">(</span><span class="st">"Enter your data as a string.</span><span class="sc">\n</span><span class="st">"</span><span class="op">);</span></span>
<span id="cb4-6"><a href=""></a> scanf<span class="op">(</span><span class="st">"</span><span class="sc">%s</span><span class="st">"</span><span class="op">,</span> buffer<span class="op">);</span> <span class="co">// No bounds check!</span></span>
<span id="cb4-7"><a href=""></a></span>
<span id="cb4-8"><a href=""></a> process_data<span class="op">(</span>buffer<span class="op">);</span></span>
<span id="cb4-9"><a href=""></a> <span class="cf">return</span><span class="op">;</span></span>
<span id="cb4-10"><a href=""></a></span>
<span id="cb4-11"><a href=""></a> <span class="co">// Returns to the return address that </span></span>
<span id="cb4-12"><a href=""></a> <span class="co">// follows buffer[] on the stack frame</span></span>
<span id="cb4-13"><a href=""></a><span class="op">}</span></span></code><button title="Copy to Clipboard" class="code-copy-button"><i class="bi"></i></button></pre></div>
<p>When writing beyond the size of <code>buffer</code> one will (eventually) overwrite the return address</p>
</section>
<section id="buffer-overflow-continued" class="slide level2">
<h2>Buffer Overflow continued</h2>
<ul>
<li>Notice that the program does not check to make sure that the user inputs 255 characters or less</li>
<li>Source code is available for many operating systems and applications
<ul>
<li>OR they can be disassembled and analyzed by the attacker</li>
</ul></li>
<li>Attacker can see that it is possible to overflow the buffer</li>
<li>Buffer is last data item on the stack frame; the return address from this function will be at a defined distance after it</li>
</ul>
</section>
<section id="buffer-overflow-continued-1" class="slide level2">
<h2>Buffer Overflow continued</h2>
<ul>
<li>Attacker can enter a character string representation of his malicious object code, long enough to fill the buffer</li>
<li>At the end of the malicious code, the attacker passes the address of variable “buffer” so that it overwrites the return address of function bogus() on the stack frame</li>
<li>When bogus() returns, it will cause a return to the buffer address, executing the malicious code in it</li>
</ul>
</section>
<section id="user-behavior-vulnerabilities" class="slide level2">
<h2>User Behavior Vulnerabilities</h2>
<ul>
<li>Poor password selection
<ul>
<li>Too short; all alphabetic; common words</li>
<li>1988 Morris worm used a list of only 432 common passwords, and succeeded in cracking many user accounts all over the Internet</li>
<li>This was the main reason the worm spread more than the creator thought it would; he did not realize that password selection was that bad!</li>
</ul></li>
</ul>
</section>
<section id="user-behavior-vulnerabilities-1" class="slide level2">
<h2>User Behavior Vulnerabilities</h2>
<ul>
<li>Opening executable email attachments
<ul>
<li>“This email is from my friend; it must be safe.” But, the friend’s PC has a virus!</li>
<li>Knowing the sender is not enough to make it safe to open</li>
<li>Virus creator can disguise the attachment to look like it is not executable</li>
<li>Remember the “Love Letter” virus!</li>
</ul></li>
<li>So only open the attachment if you know the sender, right?
<ul>
<li>What could be wrong with that?</li>
</ul></li>
</ul>
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