Objectives
After completing this chapter, you should be able to do the following:•Describe the different types of software and hardware attacks•List types of desktop defenses•Explain how to recover from an attack
Security Awareness, 3rd Edition 3
Attacks on Desktop Computers• Most attacks fall into two categories
– Malicious software attacks – Attacks on hardware
Security Awareness, 3rd Edition 4
Malicious Software Attacks
• Malware – Wide variety of damaging
or annoying attack software
– Enters a computer system without the owner’s knowledge or consent
• Primary objectives of malware– Infect a computer system
with destructive software
– Conceal a malicious actionSecurity Awareness, 3rd Edition 5
Infecting Malware
• Viruses – Malicious program that needs a
‘‘carrier’’ to survive– Two carriers
• Program or document• User
Security Awareness, 3rd Edition 6
Infecting Malware (cont’d.)• EVERY IT Security lecture must have a picture of a
padlock in it, somewhere• Viruses have performed the following functions:
– Caused a computer to crash repeatedly– Erased files from a hard drive– Installed hidden programs, such as stolen software,
which is then secretly distributed from the computer– Made multiple copies of itself and consumed all of the
free space in a hard drive– Reduced security settings and allowed intruders to
remotely access the computer– Reformatted the hard disk drive
Security Awareness, 3rd Edition 7
Infecting Malware (cont’d.)• Types of computer viruses
– File infector– Resident
– Boot– Companion
– Macro– Polymorphic
Security Awareness, 3rd Edition 8
Infecting Malware (cont’d.)• Worms
– Take advantage of a vulnerability in an application or an operating system
– Enter a system– Deposit its payload
– Immediately searches for another computer that has the same vulnerability
Security Awareness, 3rd Edition 9
Infecting Malware (cont’d.)• Different from a virus
– Does not require program or user• Actions that worms have performed include
– Deleting files on the computer – Allowing the computer to be remote-
controlled by an attacker
Security Awareness, 3rd Edition 10
Concealing Malware
• Trojan horse (or just Trojan) – Program advertised as performing one
activity but actually does something else– Typically executable programs that contain
hidden code that attacks the computer system
Security Awareness, 3rd Edition 11
Concealing Malware (cont’d.)• Rootkit
– Set of software tools – Used to break into a computer, obtain special
privileges to perform unauthorized functions– Goal is not to damage a computer directly– Go to great lengths to ensure that they are
not detected and removed
– Replace operating system commands with modified versions that are specifically designed to ignore malicious activity
– Detecting a rootkit can be difficult
Security Awareness, 3rd Edition 12
Concealing Malware (cont’d.)• Logic bomb
– Computer program or a part of a program that lies dormant until it is triggered by a specific logical event
– Once triggered, performs malicious activities– Extremely difficult to detect before they are
triggered
Security Awareness, 3rd Edition 13
Concealing Malware (cont’d.)
Table 2-1 Famous logic bombs
Security Awareness, 3rd Edition 14
Course Technology/Cengage Learning
Concealing Malware (cont’d.)• Zombie
– Infected ‘‘robot’’ computer
• Botnet– Hundreds, thousands,
or tens of thousands of zombies
• Internet Relay Chat (IRC)
– Used to remotely control the zombies
• Number of zombies and botnets is staggering
Security Awareness, 3rd Edition 15
Computer Walrus Attacks (CWA)
• Ha, there is no such thing as a Computer Walrus Attack (CWA), but maybe there should be!
• Maybe we can invent a new term?• Rule #1, never trust a walrus!• Just checking to make sure you are paying
attention during lecture!
Concealing Malware (cont’d.)
Table 2-2 Uses of botnets
Security Awareness, 3rd Edition 17
Course Technology/Cengage Learning
Hardware Attacks• Types of hardware that
is targeted includes– BIOS– USB devices– Cell phones– Physical theft of
laptop computers and information
Security Awareness, 3rd Edition 18
BIOS• Basic Input/Output System
(BIOS)– Coded program
embedded on the processor chip
– Recognizes and controls different devices on the computer system
• Read Only Memory (ROM) chip– Older systems
• PROM (Programmable Read Only Memory) chip– Newer computers– Flashing the BIOS
• Reprogramming
Security Awareness, 3rd Edition 19
USB Devices• USB (universal serial bus)• Small, lightweight, removable,
and contain rewritable storage• Common types
– USB flash memory
– MP3 players
• Primary targets of attacks to spread malware
• Allow spies or disgruntled employees to copy and steal sensitive corporate data
Security Awareness, 3rd Edition 20
USB Devices (cont’d.)
• Reduce the risk introduced by USB devices– Prohibit by written policy
– Disable with technology• Disable the USB in hardware• Disable the USB through the operating
system• Use third-party software
Security Awareness, 3rd Edition 21
Cell Phones• Portable communication
devices • Rapidly replacing wired
telephones• Types of attacks
– Lure users to malicious Web sites
– Infect a cell phone
– Launch attacks on other cell phones
– Access account information
– Abuse the cell phone serviceSecurity Awareness, 3rd Edition 22
Physical Theft
• Portable laptop computers are particularly vulnerable to theft
• Data can be retrieved from a hard drive by an attacker even after its file has been deleted
Security Awareness, 3rd Edition 23
Desktop Defenses• Defenses include:
– Managing patches– Installing antivirus software– Using buffer overflow protection– Protecting against theft
– Creating data backups– Even a cassette backup is better than no
backup
Security Awareness, 3rd Edition 24
Managing Patches
• Patch – Software security update intended to
cover vulnerabilities that have been discovered after the program was released
Security Awareness, 3rd Edition 25
Managing Patches (cont’d.)
• Automatic update configuration options for most operating systems– Install updates automatically
– Download updates but let me choose when to install them
– Check for updates but let me choose whether to download and install them
– Never check for updates
Security Awareness, 3rd Edition 26
Antivirus Software• Scan a computer’s hard drive for infections • Monitor computer activity • Examine all new documents that might contain a
virus• Drawback of AV software
– Must be continuously updated to recognize new viruses
• Should be configured to constantly monitor for viruses and automatically check for updated signature files
Security Awareness, 3rd Edition 27
Buffer Overflow Protection
• Buffer overflow– Occurs when a computer process attempts to
store data in RAM beyond the boundaries of a fixed-length storage buffer
– May cause computer to stop functioning• Windows-based system protection
– Data Execution Prevention (DEP)
– Address Space Layout Randomization (ASLR)
Security Awareness, 3rd Edition 28
Buffer Overflow Protection (cont’d.)
Figure 2-4 Buffer overflow attack
Security Awareness, 3rd Edition 29
Course Technology/Cengage Learning
Protecting Against Theft
• Applies to laptops especially
• Device lock– Steel cable and a
lock
• Software tracking system
Security Awareness, 3rd Edition 30
Creating Data Backups
• Copying data from a computer’s hard drive onto other digital media – Then storing it in a secure location
• Sophisticated hardware and software can back up data on a regular schedule
• Personal computer users– Operating system functions– Third-party software
Security Awareness, 3rd Edition 31
Creating Data Backups (cont’d.)• What information to back up
– Back up only user files– Back up all files
• Frequency of backups– Regular schedule
• RAID (Redundant Array of Independent Drives)– Uses multiple hard disk drives for increased
reliability– Several RAID configurations
• Called levelsSecurity Awareness, 3rd Edition 32
Creating Data Backups (cont’d.)
Table 2-3 Types of data backups
Security Awareness, 3rd Edition 33
Course Technology/Cengage Learning
Creating Data Backups (cont’d.)• Backup storage media
– Temporary media should not be used– Alternatives
• Portable USB hard drives• Network Attached Storage (NAS)• Internet services• Disc storage
Security Awareness, 3rd Edition 34
Creating Data Backups (cont’d.)
• Location of backup storage– Protect against not only virus attacks but also
against hardware malfunctions, user error, software corruption, and natural disasters
– Backups ideally should be stored in a location away from the device that contains the information
Security Awareness, 3rd Edition 35
Recovering from an Attack
• Basic steps to perform– Disconnect– Identify
– Disinfect– Recheck– Reinstall– Analyze
Security Awareness, 3rd Edition 36
Summary• Never trust a walrus• Malicious software (malware)
– Enters a computer system without the owner’s knowledge or consent
– Includes a wide variety of damaging or annoying software
– Infecting malware
– Concealing malware• Hardware is also the target of attackers• Tactics for defending desktop systems• Basic steps to disinfect and restore a computer
Security Awareness, 3rd Edition 37
Top Related