Textbook Notes (369,205)
Canada (162,462)
CIS 1000 (58)
Zoe Zhu (26)
Chapter 9

Chapter 9.docx

6 Pages
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Department
Computing and Information Science
Course Code
CIS 1000
Professor
Zoe Zhu

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Chapter 9: Securing Your System Keeping Your Data Safe - Cybercrimes are criminal acts conducted by cybercriminals through the use of computers - Cybercriminals are individuals who use computers, networks and the internet to perpetrate crime - Computer users need to protect themselves from becoming victims of cybercriminals - The Internet Crime Complaint Centre (IC3) processed more than 275,000 complaints related to internet crime in 2008 - The majority of complaints (more than 58%) were related to three key areas: Internet auction fraud, non-delivery of merchandise or failure to pay - Much of the credit card fraud is perpetrated when credit card numbers are stolen by phishing (tricking people into revealing information) or by virus programs that gather credit card data - Non-fraud-related complaints pertained to issues such as computer intrusions, unsolicited e-mail, and child pornography - Creating and disseminating computer viruses is one of the most widespread types of cybercrimes Computer Threats: Viruses - A computer virus is a computer program that attaches itself to another computer program (known as the host program) and attempts to spread to other computers when files are exchanged - Viruses normally attempt to hide within the code of a host program to avoid detection - Viruses, by definition, have a method to spread themselves - Virus creation and deployment is a form of cybercrime - A computer virus’s main purpose is to replicate itself and copy its code into as many other files as possible - Although virus replication can slow down networks, it is not usually the main threat - The majority of viruses have secondary objectives or side effects, ranging from displaying annoying messages on the computer screen to destroying files or the contents of entire hard drives - If the computer is exposed to a file infected with a virus, the virus will try to copy itself and infect a file on your computer - Shared disks or flash drives are common sources of virus infection, as is e-mail - Downloading or running a file attached to an e-mail is how a computer becomes effected - Types of viruses:  Boot-Sector Viruses  A boot-sector virus replicates itself into a hard drive’s master boot record  The master boot record is a program that executes whenever a computer boots up, ensuring that the virus will be loaded into memory immediately, before anti-viruses can load  Logic Bombs and Time Bombs  A logic bomb is a virus that is triggered when certain logical conditions are met  A time bomb is a virus that is triggered by the passage of time or on a certain date  Worms  A worm is slightly different from a virus in that a worm attempts to travel between systems through network connections to spread an infection  Script and Macro Viruses  A script is a series of commands (a mini-program) that is executed without your knowledge  A macro virus is a virus that attaches itself to a document  E-mail viruses use the address book in the victim’s email system to distribute the virus  Encryption Viruses  When encryption viruses infect your computer, they run a program that searches for common types of data files and compresses them using a complex encryption key that renders your files unusable - Types of virus classifications:  A polymorphic virus changes its own code to avoid detection  A multipartite virus is designed to infect multiple file types in an effort to fool the antivirus software that is looking for it  Stealth viruses temporarily erase their code from the files where they reside and then hide in the active memory of the computer Computer Safeguard: Antivirus Software - Antivirus software is software specifically designed to detect viruses and protect computers and files from harm - Although antivirus software is designed to detect suspicious activity on your computer at all times, you should run an active virus can on your entire system at least once a week - Most antivirus software looks for virus signatures in files – a virus signature are portions of the virus code that are unique to that particular computer virus - Antivirus software scans files when they’re opened or executed - If it detects a virus signature or suspicious activity, it stops the execution of the file and notifies you it has detected a virus; usually it gives you the choice of deleting or repairing the infected file and places the virus in a secure area – this is called quarantining - Through inoculation, the antivirus software records key attributes about files on your computer and keeps these statistics in a safe place on your hard drive - Antivirus software catches known viruses effectively; thus your computer can still be attacked by a virus that your antivirus software does not recognize – to minimize this risk, keeping your antivirus software up to date is key - Other ways to protect your system are:  Keeping your computer’s antivirus and operating system (OS) software up to date  Loading security patches as soon as they are available  Enabling automatic updates for both the OS and all other software loaded on your computer - To keep your instant messaging sessions safe, follow these precautions: 1. Allow contact only from users on your buddy or friends list 2. Never automatically accept transfers of data 3. Avoid using instant messaging programs on public computers - Malicious websites can be set up to attack your computer by downloading harmful software onto your computer. According to research conducted by Google, an attack known as a drive-by download, is common and affects almost 1 in 1000 web pages - Although many people decide to receive updates automatically, there are several options you can choose from in Windows. The following options are noteworthy:  Option 1: Install updates automatically  Option 2: Download updates but let me choose whether to install them  Option 3: Check for updates but let me choose whether to download and install them  Option 4: Give me recommended updates  Option 5: Microsoft update Computer Threats: Hackers - A hacker is defined as anyone who unlawfully breaks into a computer system, whether it's an individual computer or a network - A hacker who breaks into systems just for the challenge of it may refer to himself/herself as a white- hat hacker – they tout themselves as experts who are performing a needed service for society by helping companies realize the vulnerabilities that exist in their systems - White hat hackers call hackers who use their knowledge to destroy information or for illegal gain black hat hackers - Amateur hackers are referred to as script kiddies – script kiddies don’t create the programs they use to hack into computer systems; instead, they use tools created by skilled hackers - If you perform financial transactions online, credit card and bank account information can reside on your hard drive and may be detectable by a hacker - Even if this data is not stored on your computer, a hacker might be able to capture it when you’re online by using a packet sniffer - Data travels through the internet in small pieces, each called a packet - A packet sniffer is a program that looks at each packet as it travels on the internet – not just those that are addressed to a particular computer, but all packets - Some packet sniffers are configured to capture all the packets into memory, whereas others capture only those packets that contain specific content - Once a hacker has access to credit card information, he/she can either use it to purchase items illegally or sell the information to someone who will - If hackers can gather enough information in conjunction with your credit card info, they may be able to commit identity theft - Identify theft is characterized by someone using personal information about you to assume your identity for the purpose of defrauding others - A Trojan horse is a program that appears to be something useful or desirable, but something malicious runs in the background without your knowledge - Often, the malicious activity perpetrated by a Trojan horse program is the installation of a backdoor program that allows hackers to take almost complete control of your computer without your knowledge - A computer that a hacker controls in this manner is referred to as a zombie - In a denial-of-service (DoS) attack, legitimate users are denied access to a computer system because a hacker is repeatedly making requests of that computer system through a computer he/she has taken over as a zombie - Launching a DoS attack on a computer system from a single computer is easy to trace - Most savvy hackers use a distributed denial-of-service (DDoS) attack, which launches DoS attacks from more than one zombie at the same time - A botnet is a large group of software programs (called robots or bots) that runs autonomously on zombie computers - Logical ports are virtual communications gateways or paths that allow a computer to organize requests for information from other networks or computers Restricting Access to Your Digital Assets - A firewall is a program or hardware device designed to protect computers from hackers - A firewall spe
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