Computer Security and Viruses
What is a virus?
Not unlike a virus in nature, a computer virus is a piece of code (a program) that replicates by being copied or it initiates its copying to another program, computer boot sector or document.
¨ Can be transmitted as e-mail attachments, in a download file or be present on diskette.
¨ Some are immediate in the harm they do
¨ Some lie dormant until they are initiated by circumstance or time
¨ Often increase their chance of spreading by infecting files that are accessed by multiple computers on a networked system
Harmful viruses can erase data, cause a hard drive to fail (require reformatting), yet some can be playful with no ill intent.
Types of Viruses
File infectors
¨ Attach themselves to program files usually aimed at .com or .exe files
¨ Loading the file loads the virus
¨ Some arrive as independent programs or scripts attached to e-mail
System or boot-record infectors
¨ Infect executable code found on system areas of the disk or hard drive.
¨ Attached to the boot sector on a disk they are undetectable until you reboot the computer, and can make the computer inaccessible
Macro viruses
¨ Most common and causes the least damage
¨ Often insert unwanted words and phrases into documents
Protection
¨ Know your sources are clean,
o avoid sites that show they have had “previous problems” look at site advisor notices
o only open email from sources you know
¨ Run anti-virus software
o Can be configured to scan emails prior to them getting in your “inbox”
o Searches hard drive and floppy disks for potential threats
o e.g. Of free software AVG, Avast, Avira and Kaspersky
So, where are the Trojans, worms, spyware, dishonest adware etc??
Malware
¨ malicious software – any software that executes a process without a users consent
o designed to disrupt computer operation
o collect sensitive information
o gain unauthorized access to a system
Types of Malware
Worms
¨ self-replicating computer program
¨ uses the network to send itself to other computers
¨ does not attach to an existing program
¨ usually cause harm to a network (even if only taking up bandwidth)
Trojan horse
¨ usually make copies of themselves (but not usually), steal information, or harm the host computer
¨ they appear as helpful programs
¨ downloaded by “Drive-by downloads” (download authorized by a unknowing user)
¨ worst one is a program that claims to get rid of viruses, but actually introduces them to the computer
Spyware
¨ collects information about a user from the computer (personal info, internet surfing habits)
¨ hidden from user and hard to detect
¨ can be used to monitor a networks activity
Adware
¨ software package which automatically allows for advertisement (often pop-ups)
¨ can be spyware
Rootkit
¨ Stealthy software designed to hide certain programs from detection.
¨ Enables continued privileged access to a computer (as “root” or administrator of the system)
Protection
¨ If you suspect malware us an anti-malware application (e.g. Malwarebytes, Spyware Doctor, Spybot S&D, SuperAntiSpyware)
¨ Make sure you have anti-virus software that includes malware as well
Firewall
¨ A firewall is a program or a hardware device that can be used to help protect a network from hackers who might try to break in and gain access to your data.
¨ The firewall filters the information coming through the Internet connection into your personal computer or into a company's network.
¨ It is set up to allow mainly one way access
o Your data can get out but only that which has been given permission can get back in
o Data that cannot get in has been “blocked”
¨ Anyone who has access to the internet should have a firewall installed.
Computer Maintenance and Security
¨ use a security software with a firewall
o (Norton’s, McAfee, other free anti-virus etc)
¨ Password protect wireless networks
¨ log in as a user not as an administrator (protects OS)
¨ Maintain security updates
o Patches, hot fixes and service packs
o Only 21% are technically fixes, most are software upgrades but improves functionality of system and of hardware drivers
¨ Don’t click on random links
¨ Beware of e-mail attachments from unknown sources
¨ Don’t propagate chain mail or virus hoaxes (mail that tells you to delete OS system files because they are viruses)
¨ Be careful of software you download from internet
¨ Restrict remote access
¨ Backup important files and documents
o in case of intrusion
o software failure
To maintain your system:
¨ Use “Add or Remove programs” from the Control Panel when removing unused applications
o Removes information from your system registry (database that holds configuration information about your Windows operating system)
¨ Defragment your hard drive occasionally (Disk Defragmenter)
o Places all fragments of a program together
§ increase available space on the hard drive
§ increases the efficiency and performance of the computer
¨ Keep system cool and clean
¨ Unplug the system before touching anything inside
o Also ground yourself and the system as well.