This article discusses the following:
- How to determine whether your computer is infected with a computer virus, a worm, or a trojan
- How to recover from an infection
- How to prevent future infections from a computer virus
What is a computer virus?
A computer virus is a small software program that spreads from one computer to another computer and that interferes with computer operation. A computer virus may corrupt or delete data on a computer, use an e-mail program to spread the virus to other computers, or even delete everything on the hard disk.
Computer viruses are most easily spread by attachments in e-mail messages or by instant messaging messages. Therefore, you must never open an e-mail attachment unless you know who sent the message or unless you are expecting the e-mail attachment. Computer viruses can be disguised as attachments of funny images, greeting cards, or audio and video files. Computer viruses also spread by using downloads on the Internet. Computer viruses can be hidden in pirated software or in other files or programs that you may download.
Symptoms of a computer virus
If you suspect or confirm that your computer is infected with a computer virus, obtain the current antivirus software. The following are some primary indicators that a computer may be infected:
- The computer runs slower than usual.
- The computer stops responding, or it locks up frequently.
- The computer crashes, and then it restarts every few minutes.
- The computer restarts on its own. Additionally, the computer does not run as usual.
- Applications on the computer do not work correctly.
- Disks or disk drives are inaccessible.
- You cannot print items correctly.
- You see unusual error messages.
- You see distorted menus and dialog boxes.
- There is a double extension on an attachment that you recently opened, such as a .jpg, .vbs, .gif, or .exe. extension.
- An antivirus program is disabled for no reason. Additionally, the antivirus program cannot be restarted.
- An antivirus program cannot be installed on the computer, or the antivirus program will not run.
- New icons appear on the desktop that you did not put there, or the icons are not associated with any recently installed programs.
- Strange sounds or music plays from the speakers unexpectedly.
- A program disappears from the computer even though you did not intentionally remove the program.
Note These are common signs of infection. However, these signs may also be caused by hardware or software problems that have nothing to do with a computer virus. Unless you run the Microsoft Malicious Software Removal Tool, and then you install industry-standard, up-to-date antivirus software on your computer, you cannot be certain whether a computer is infected with a computer virus or not.
Protecting yourself against computer worms
Computer worms which spread through vulnerabilities in network services can best be protected against by keeping up-to-date in installing patches provided by operating system and application vendors. This includes worms like SQL Slammer and Blaster.
Computer worms which spread like trojan horses can best be defended against by not opening attachments in your e-mail. These infected attachments are not limited to .EXE files. Microsoft Word and Excel files can contain macros which spread infection.
Some people would say that the best way to protect yourself against computer worms is not to run Microsoft softwJaise’s 4D world › Create New Post — WordPressare. 
- Worm
- Like a virus, a worm is also a program that propagates itself. Unlike a virus, however, a worm can spread itself automatically over the network from one computer to the next. Worms are not clever or evil, they just take advantage of automatic file sending and receiving features found on many computers.
- Trojan horse
- This is a very general term, referring to programs that appear desirable, but actually contain something harmful. The harmful contents could be something simple, for example you may download what looks like a free game, but when you run it, it erases every file in that directory. The trojan’s contents could also be a virus or worm, which then spread the damage. See our Trojan horse help page for more information.
- Remember the “Love Bug”? Is it a virus, worm, or trojan? Answer: all three! It’s a trojan because it pretends to be a love letter when it is really a harmful program. It’s a virus because it infects all the image files on your disk, turning them into new trojans. Finally, it’s also a worm because it propagates itself over the internet by hiding in trojans that it sends out using your email address book, IRC client, etc.
-
Phishers, Virus Writers Exploit Global Financial Crisis
Security experts and the federal government are warning that scam artists are leveraging public concern over the global financial crisis to steal sensitive financial data and spread malicious software.
In an alert posted Thursday, the Federal Trade Commission urged Internet users to be on guard against e-mails that look as if they come from a financial institution that recently acquired a consumer’s bank, savings and loan, or mortgage.
“In fact, these messages may be from ‘phishers’ looking to use personal information — account numbers, passwords, Social Security numbers — to run up bills or commit other crimes in a consumer’s name,” the FTC said.
Security firm Arbor Networks details two recent malware attacks that try to trick recipients into opening an e-mail attachment. One e-mail, claiming to have been sent by the Federal Deposit Insurance Corp., warns recipients that their bank accounts were involved in fraudulent activity. The attached file, disguised as a written account of that activity, is in fact a program designed to swipe passwords from the victim’s PC.
Another e-mail making the rounds, according to Arbor senior security researcher Jose Nazario, appears to come from Wachovia, which is slated to be acquired by Wells Fargo. The message tells recipients they need to install a special security certificate into their Web browser in order to do online banking with the new institution. The attached cert in question is, of course, more malware.
Phishers also are capitalizing on the banking crisis. Phishtank.com, a community-based effort to verify and track phishing Web sites, found this recent phish, which tries to convince Citibank customers to enter their account details at a fake Citibank Web site. This cleverly worded phish promises customers concerned about keeping their assets in U.S. banks “the option to have your account moved on our servers abroad.”
Because we value you as our customer and share your concerns about your financial assets, we now offer you the option to have your account moved on our servers abroad. This will prevent any financial loss from your account in case the U.S. financial system collapses. This option is free of charge. After successfully completing the required steps, your account will be moved on our new servers located abroad. You won’t feel any negative impact of account movement and you won’t have any problems accessing your money from anywhere in the world.
No doubt, people who fall for this scam will have their funds transferred abroad: straight into bank accounts controlled by organized criminals.
I think it’s fair to assume we can expect attacks exploiting public concern over the banking sector to continue and even increase in their sophistication. Remember, not all e-mail-based phishing and malware attacks are alike: Scammers also are using very targeted techniques, addressing recipients by name and including other details that can increase the apparent authenticity of the come-ons.
Remember, never click on or open attachments in e-mails that you weren’t expecting, even if they appear to come from someone you know. Also, banks should never ask for any personal information via e-mail, and I’m not aware of a single legitimate instance of a bank asking customers to install anything on their computers.
The FTC advisory includes a long list of other excellent security and privacy tips:
* Don’t reply to an email or pop-up message that asks for personal or financial information, and don’t click on links in the message – even if it appears to be from your bank. Don’t cut and paste a link from the message into your Web browser, either. Phishers can make links look like they go one place, but actually redirect you to another.
* Some scammers call with a recorded message, or send an e-mail that appears to be from an institution, and ask you to call a phone number to update your account. Because they use Voice over Internet Protocol technology, the area code you call does not reflect where the scammers are. To reach an institution you do business with, call the number on your financial statements.
* Use anti-virus and anti-spyware software, as well as a firewall, and update them regularly.
* Don’t e-mail personal or financial information. E-mail is not a secure way to send sensitive information.
* Review your financial account statements as soon as you receive them to check for unauthorized charges.
* Be cautious about opening any attachment or downloading any files from e-mails you receive, regardless of who sent them. These files can contain viruses or other software that can weaken your computer’s security.
* Forward phishing e-mails to spam@uce.gov – and to the institution or company impersonated in the phishing e-mail. You also may report phishing e-mail to reportphishing@antiphishing.org. The Anti-Phishing Working Group, a consortium of ISPs, security vendors, financial institutions and law enforcement agencies, uses these reports to fight phishing.
* If you’ve been scammed, visit the Federal Trade Commission’s Identity Theft Web site for important information on next steps to take.
Entries (RSS)