If your PC is infected:

What to Do If Your Computer Is Infected

Sometimes even an experienced user will not realise that a computer is infected with a virus. This is because viruses can hide among regular files, or camoflage themselves as standard files. This section contains a detailed discussion of the symptoms of virus infection, how to recover data after a virus attack and how to prevent data from being corrupted by malware.

Symptoms of infection

There are a number of symptoms which indicate that your computer has been infected. If you notice "strange things" happening to your computer, namely:

• unexpected messages or images are suddenly displayed
• unusual sounds or music played at random
• your CD-ROM drive mysteriously opens and closes
• programs suddenly start on your computer
• you receive notification from your firewall that some applications have attempted to connect to the Internet, although you did not initiate this, then it is very likely that your computer has been infected by a virus

Additionally, there are some typical symptoms which indicate that your computer has been infected via email:

• your friends mention that they have received messages from your address which you know you did not send
• your mailbox contains a lot of messages without a sender's e-mail address or message header

These problems, however, may not be caused by viruses. For example, infected messages that are supposedly coming from your address can actually be sent from a different computer.

There is a range of secondary symptoms which indicate that your computer may be infected:

• your computer freezes frequently or encounters errors
• your computer slows down when programs are started
• the operating system is unable to load
• files and folders have been deleted or their content has changed
• your hard drive is accessed too often (the light on your main unit flashes rapidly)
• Microsoft Internet Explorer freezes or functions erratically e.g. you cannot close the application window

90% of the time the symptoms listed above indicate a hardware or software problem. Although such symptoms are unlikely to be caused by a virus, you should use your antivirus software to scan your computer fully.

What you should do if you notice symptoms of infection

If you notice that your computer is functioning erratically

1. Don't panic! This golden rule may prevent the loss of important data stored in your computer and help you avoid unnecessary stress.
2. Disconnect your computer from the Internet.
3. If your computer is connected to a Local Area Network, disconnect it.
4. If the computer cannot boot from the hard drive (error at startup), try to start the system in Safe Mode or from the Windows boot disk
5. Before taking any action, back up all critical data to an external drive (a floppy disk, CD, flash memory, etc.).
6. Install antivirus software if you do not have it installed.
7. Download the latest updates for your antivirus database. If possible, do not use the infected computer to download updates, but use a friend's computer, or a computer at your office, an Internet cafe, etc. This is important because if you are connected to the Internet, a virus can send important information to third parties or may try to send itself to all email addresses in your address book. You may also be able to obtain updates for your antivirus software on CD-ROM from the software vendors or authorized dealers.
8. Perform a full system scan.

If no viruses are found during a scan

If no viruses are found during the scan and the symptoms that alarmed you are classifed, you probably have no reason to worry. Check all hardware and software installed in your computer. Download Windows patches using Windows Update. Deinstall all unlicensed software from your computer and clean your hard drives of any junk files.

If viruses are found during a scan

A good antivirus solution will notify you if viruses are found during a scan, and offer several options for dealing with infected objects.

In the vast majority of cases, personal computers are infected by worms, Trojan programs, or viruses. In most cases, lost data can be successfully recovered.

1. A good antivirus solution will provide the option to disinfect for infected objects, quarantine possibly infected objects and delete worms and Trojans. A report will provide the names of the malicious software discovered on your computer.
2. In some cases, you may need a special utility to recover data that have been corrupted. Visit your antivirus software vendor's site, and search for information about the virus, Trojan or worm which has infected your computer. Download any special utilities if these are available.
3. If your computer has been infected by viruses that exploit Microsoft Outlook Express vulnerabilities, you can fully clean your computer by disinfecting all infected objects, and then scanning and disinfecting the mail client's databases. This ensures that the malicious programs cannot be reactivated when messages which were infected prior to scanning are re-opened. You should also download and install security patches for Microsoft Outlook Express.
4. Unfortunately, some viruses cannot be removed from infected objects. Some of these viruses may corrupt information on your computer when infecting, and it may not be possible to restore this information. If a virus cannot be removed from a file, the file should be deleted.

If your computer has suffered a severe virus attack

Some viruses and Trojans can cause severe damage to your computer:

1. If you cannot boot from your hard drive (error at startup), try to boot from the Windows rescue disk. If the system can not recognize your hard drive, the virus has damaged the disk partition table. In this case, try to recover the partition table using scandisk, a standard Windows program. If this does not help, contact a computer data recovery service. Your computer vendor should be able to provide contact details for such services.

If you have a disk management utility installed, some of your logical drives may be unavailable when you boot from the rescue disk. In this case, you should disinfect all accessible drives, reboot from the system hard drive and disinfect the remaining logical drives.

2. Recover corrupted files and applications using backup copies after you have scanned the drive containing this data.

Diagnosing the problem using standard Windows tools

Although this is not recommended unless you are an experience user, you may wish to:

• check the integrity of the file system on your hard drive (using CHKDSK program) and repair file system errors. If there are a large number of errors, you must backup the most important files to removable storage media before fixing the errors
• scan your computer after booting from the Windows rescue disk
• use other standard Windows tools, for example, the scandisk utility

For more details on using these utilities, refer to the Windows Help topics.

If nothing helps

If the symptoms described above persist even after you have scanned your computer, and checked all installed hardware and software and your hard drive using Windows utilities, you should send a message with a full description of the problem to your antivirus vendor's technical support department.

Some antivirus software developers will analyse infected files submitted by users.

After you have eradicated the infection

Once you have eradicated the infection, scan all disks and removable storage media that may be infected by the virus.

Make sure that you have appropriately configured antivirus software installed on your computer.

Practice safe computing.

All of these measures will help prevent your computer getting infected in the future.

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Who Writes Mal ware Programs and Why????????

Who Writes Malicious Programs and Why?

Virus writers: four general types

Virus writers belong to one of four broad groups: cyber-vandals, who can be divided into two categories, and more serious programmers, who can again be split into two groups.

Cyber vandalism - stage 1

In the past, most malware was written by young programmers: kids who just had learned to program who wanted to test their skills. Fortunately most of these programs did not spread widely - the majority of such malware died when disks were reformatted or upgraded. Viruses like these were not written with a concrete aim or a definite target, but simply for the writers to assert themselves.

Cyber vandalism - stage 2

The second largest group of contributors to malware coding were young people, usually students. They were still learning programming, but had already made a conscious decision to devote their skills to virus writing. These were people who had chosen to disrupt the computing community by committing acts of cyber hooliganism and cyber vandalism. Viruses authored by members of this group were usually extremely primitive and the code contained a large number of errors.

However, the development of the Internet provided space and new opportunities for these would-be virus writers.Numerous sites, chat rooms and other resources sprang up where anyone could learn about virus writing: by talking to experienced authors and downloading everything from tools for constructing and concealing malware to malicious program source code.

Professional virus writers

And then these 'script kiddies' grew up. Unfortunately, some of them did not grow out of virus writing. Instead, they looked for commercial applications for their dubious talents. This group remains the most secretive and dangerous section of the computer underground: they have created a network of professional and talented programmers who are very serious about writing and spreading viruses.

Professional virus writers often write innovative code designed to penetrate computers and networks; they research software and hardware vulnerabilities and use social engineering in original ways to ensure that their malicious creations will not only survive, but also spread widely.

Virus researchers: the 'proof-of-concept' malware authors

The fourth and smallest group of virus writers is rather unusual. These virus writers call themselves researchers, and they are often talented programmers who devote their skills to developing new methods for penetrating and infecting systems, fooling antivirus programs and so forth. They are usually among the first to penetrate new operating systems and hardware. Nevertheless, these virus writers are not writing viruses for money, but for research purposes. They usually do not spread the source code of their 'proof of concept viruses', but do actively discuss their innovations on Internet resources devoted to virus writing.

All of this may sound innocent or even beneficial. However, a virus remains a virus and research into new threats should be conducted by people devoted to curing the disease, not by amateurs who take no responsibility for the results of their research. Many proof of concept viruses can turn into serious threats once the professional virus writers gain access to them, since virus writing is a source of income for this group.

Why write viruses?

Fraud

The computer underground has realised that paid for Internet services, such as Internet access, email and web hosting, provides new opportunities for illegal activity with the additional satisfaction of getting something for nothing. Virus writers have authored a range of Trojans which steal login information and passwords to gain free access to other users' Internet resources.

The first password stealing Trojans appeared in 1997: the aim was to gain access to AOL. By 1998 similar Trojans appeared for all other major Internet service providers. Trojans stealing log in data for dial-up ISPs, AOL and other Internet services are usually written by people with limited means to support their Internet habit, or by people who do not accept that Internet resources are a commercial service just like any other, and must therefore be paid for.

For a long time, this group of Trojans constituted a significant portion of the daily 'catch' for antivirus companies worldwide. Today, the numbers are decreasing in proportion to the decreasing cost of Internet access.

Computer games and software license keys are another target for cyber fraud. Once again, Trojans providing free access to these resources are written by and for people with limited financial resources. Some hacking and cracking utilities are also written by so-called 'freedom fighters', who proclaim that all infomration should be shared freely throughout the computing community. However, fraud remains a crime, no matter how noble the aim is made out to be.

Organised cyber crime

The most dangerous virus writers are individuals and groups who have turned professional. These people either extract money directly from end users (either by theft or by fraud) or use zombie machines to earn money in other ways, such as creating and selling a spamming platform, or organizing DoS attacks, with the aim here being blackmail.

Most of today's serious outbreaks are caused by professional virus writers who organize the blanket installations of Trojans to victim machines. This may be done by using worms, links to infected sites or other Trojans.

Bot networks

Currently, virus writers either work for particular spammers or sell their wares to the highest bidder. Today, one standard procedure is for virus writers to create bot networks, i.e. networks of zombie computer infected with identical malicious code. In the case of networks used as spamming platforms, a Trojan proxy server will penetrate the victim machines. These networks number from a thousand to tens of thousands of infected machines. The virus writers then sell these networks to the highest bidder in the computer underground.

Such networks are generally used as spamming platforms. Hacker utilities can be used to ensure that these networks run efficiently; malicious software is installed without the knowledge or consent of the user, adware programs can be camoflaged to prevent detection and deletion, and antivirus software may be attacked.

Financial gain

Apart from servicing spam and adware, professional virus writers also create Tojan spies which they use to steal money from e-wallets, Pay Pal accounts and/or directly from Internet bank accounts. These Trojans harvest banking and payment information from local machines or even corporate servers and then forward it to the master.

Cyber extortion

The third major form of contemporary cyber crime is extortion or Internet rackets. Usually, virus writers create a network of zombie machines capable of conducting an organized DoS attack. Then they blackmail companies by threatening to conduct a DoS attack against the corporate website. Popular targets include estores, banking and gambling sites, i.e. companies whose revenues are generated directly by their on-line presence.

Other malware

Virus writers and hackers also ensure that adware, dialers, utilities that redirect browsers to pay-to-view sites and other types of unwanted software function efficiently. Such programs can generate profits for the computer underground, so it's in the interests of virus writers and hackers to make sure that these programs are not detected and are regularly updated.

In spite of the media attention given to young virus writers who manage to cause a global epidemic, approximately 90% of malicious code is written by the professionals. Although all of four groups of virus writers challenge computer security, the group which poses a serious, and growing threat is the community of professional virus writers who sell their services.

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