Desktop Security After completing this lesson, you should be able to do the following: Describe the different types of software and hardware attacks List types of desktop defences Explain how to recover from an attack 1

Attacks on Desktop Computers Most attacks fall into two categories –Malicious software attacks –Attacks on hardware 2

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 action 3

Infecting Malware Viruses –Malicious program that needs a ‘‘carrier’’ to survive –Two carriers Program or document User 4

Infecting Malware (cont’d.) 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 5

Infecting Malware (cont’d.) Types of computer viruses –File infector –Resident –Boot –Companion –Macro –Polymorphic 6

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 vulnerabiliy 7

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 8

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 9

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 10

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 11

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 12

Hardware Attacks Types of hardware that is targeted includes –BIOS –USB devices –Mobile phones –Physical theft of laptop computers and information 13

BIOS Basic Input/Output System (BIOS) –Coded program embedded on the processor chip –Recognizes and controls different devices on the computer system PROM (Programmable Read Only Memory) chip –Newer computers –Flashing the BIOS Reprogramming 14

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 15

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 16

Mobile Phones Portable communication devices Rapidly replacing wired telephones Types of attacks –Lure users to malicious Web sites –Infect a mobile phone –Launch attacks on other mobile phones –Access account information –Abuse the mobile phone service 17

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 18

Desktop Defences Defences include: –Managing patches –Installing antivirus software –Using buffer overflow protection –Protecting against theft –Creating data backups 19

Managing Patches Patch –Software security update intended to cover vulnerabilities that have been discovered after the program was released 20

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 21

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 22

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) 23

Buffer Overflow Protection (cont’d.) Buffer overflow attack 24

Protecting Against Theft Applies to laptops especially Device lock –Steel cable and a lock Software tracking system 25

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 26

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 levels 27

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 28

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 29

Recovering from an Attack Basic steps to perform –Disconnect –Identify –Disinfect –Recheck –Reinstall –Analyze 30

Summary 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 31