Security & Viruses

1. Security & Viruses

2. Security & Protection • The three main causes of disaster are: • Human Error – THINK before you act • Deleting the wrong files • Editing old or incorrect versions of files • Viruses • Hardware – usually the least likely to happen and to cause problems, but the most frequently cited by users.

3. Prevention Checklist To prevent horrendous disasters: • Run a clean system • Keep an emergency disk • Perform regular backups • Run anti-virus checks • Secure your power

4. Run a Clean System • Regularly defrag your hard drive • Keeps files tight for efficient operation • Easier to backup • Easier to remove in case of emergency

5. Keep an Emergency Disk • Keep an up-to-date emergency or boot disk. • Creation of an XP boot disk requires: • A blank floppy disk • A Windows XP CD-Rom or an operational XP-based computer • The floppy must then be formatted and select files must be copied from the CD. • Entire process may be found from a link on the 110 home page.

6. Perform Regular Backups • Usually start with a full backup • Do incremental backups on a regular periodic basis – ie weekly, monthly. • Occasionally check backups for viruses. • Keep your hard drive organized for ease of backup.

7. Run Anti-Virus Checks • Scan all email attachments • Scan all disks, CD’s, and files • Periodically scan entire system • Keep virus signatures up to date • Set your CMOS to a boot order of C:, A:

8. Computer Viruses • A computer virus is a program that contains instructions to initiate some sort of “event” that affects the infected computer. Each virus has a unique event associated with it. These events and there effects may range from harmless to devastating. For example: • an annoying message on your screen • reduced memory or disk space • data modification • files overwritten or damaged • hard disk erased

9. Virus Types • Boot viruses – place their code in the disk sector whose code the machine will automatically execute when booting. • File viruses – attach to “program files” and run with the infected program. • Macro viruses – another type of file virus, except written in a macro language (i.e. VBA) • Script viruses – viruses that infect scripting languages like JavaScript and VBScript

10. Virus Types – Cont. • Multi-partite viruses – are “combination infectors” that infect such things as boot sectors and files at the same time • Worms – a program like a virus that spreads via network connections • Non-viral Malware – “Remote Access Trojans” or RATS. Is a program that tries to trick a user into running a program on their computer which then opens a “back door” whereby the attacker can attach to the victims computer. They and worms are becoming popular because of “always on” systems. • Spyware - is any technology that aids in gathering information about a person or organization without their knowledge. On the Internet spyware is programming that is put in someone's computer to secretly gather information about the user and relay it to advertisers or other interested parties. Spyware can get in a computer as a software virus or as the result of installing a new program.

11. Anti-Virus Tools • The use of anti-virus tools makes detecting and eradicating viruses a much easier task. • Two types of anti-virus tools are: • Scanners which examine every file on a specific disk looking for “signatures” of known viruses. • Monitors that run on the system continuously and “watch over” all operations being performed by the O/S looking for suspicious actions. • Check out the 110 Web Site for virus sites.

12. Tips to Protect Computer Users From Virus Threats • Install anti-virus software and keep the virus definitions up to date. • Don't automatically open attachments • Scan all incoming email attachments • Get immediate protection. Anti-virus • Update your anti-virus software frequently.

13. Tips to Protect Computer Users From Virus Threats – Cont. • Avoid downloading files you can't be sure are safe. • Don't boot from a floppy disk. • Don't share disks. • Scan external disks before using them. • Have a “Firewall” for an always-on system. • Use common sense. Always err on the side of safety.

14. Chkdisk • Most hard drive problems are invisible, they do not prevent your hard drive from operating, they waste drive space and reduce overall performance. • chkdisk is a disk analysis and repair tool used to check a drive for errors and repair many problems it finds. • Problems chkdisk can find and repair: • FAT or NTFS errors • Illegal names, dates, and times • File system structure problems, such as lost clusters and cross-linked files. (the most common problem found) • Directory tree errors • Defects on disk itself, such as bad tracks.

15. ChkDisk - cont. • Lost clusters and cross-linked files are usually caused by three common system problems: • Improper shutdowns • Application lockups • System crashes • It is recommended that you run Chkdisk at least once a month • To run Chkdisk from Windows 2000 or Windows XP either: • Invoke from the properties menu (see next slide) or • Run the chkdsk program as follows: • Click Start • Highlight Programs followed by Accessories • Choose Command Prompt • At the prompt type - chkdsk c: /f

16. Disk Defragmenter • A Disk defragmenter will reorganize data on a file system in order to improve performance. • Disk defragmentation takes a great deal of time. • In Win XP the defragmenter is available as shown above • The Win ‘98 Disk defragmenter is available from the Accessories/System Tools menu