About viruses: Main sources of threats penetration

At the present time the main types of threats for the information on your computer are internet and e-mail. Great number of Malware includes viruses, Trojans, worms, that can penetrate your computer while you read an email message or an article on the Internet, search the information, open web-sites, download, and install software on your computer.

Malware spreads flash-like and harms your computer within a second so that it is very costly to restore your computer. The matter is not only in damaging the data, but in unauthorized access to the system, breaking its integrity, information leakage.

Spam – another important source of “troubles” – should not be forgotten about. Unrequired mail correspondence (spam) cam harm more than some Malware. Not being a source of direct threat, spam leads to waste of working time and can cause unjustified financial losses, these losses increase hundred and thousand times when it refers to a corporative computer network.

Each user who widely deploys modern informational resources should know what threats him/her and what consequences this or that malicious impact may cause. The most malicious sources of threats penetration are:

• Internet – global information net is the main source of spreading any type of Malware. As a rule viruses and other malicious programs are located on popular web-sites in Internet, “disguising” as useful and free software. Abound of scripts that run automatically when opening a web-site may also contain Malware.
• Email – mails received by the user stored in the mail bases, may contain viruses as well. Malware can be either in attachment or in the body of a message. As a rule mails contain viruses and mail worms. You can infect the data on your PC either when opening the massage or when saving on a disc a file attached to the message. Mail can also be the source of two other threats: spam and phishing. If spam causes mainly waste of time, then the aim of phishing is your confidential information (e.g. number of your credit card).
• Vulnerabilities in software – so called “holes” in software are the main source of hacker attacks. Vulnerabilities grant hacker remote access to your PC, and correspondingly to your personal data, to the LAN/Ethernet resources available to you, and other sources of information.
• Removable data carriers – removable drives and memory expansion cards (flash-cards) are still widely used to transfer information. By running a file saved on a removable carrier, you can harm the data on your computer with a virus and then involuntarily spread this virus onto other drives of your computer.

 If you suspect that your computer is infected with viruses, we recommend you, then install a trial version of Kaspersky Internet Security, update databases and run full computer scan. You can also download and install a free utility Kaspersky Virus Removal Tool 2011.

About viruses: Types of known threats

To know what can threat your data you should know what malicious programs (Malware) exist and how they function. Malware can be subdivided in the following types:

Viruses: programs that infect other programs by adding to them a virus code to get access at an infected file start-up. This simple definition discovers the main action of a virus – infection. The spreading speed of viruses is lower than that of worms.

Worms: this type of Malware uses network resources for spreading. This class was called worms because of its peculiar feature to “creep” from computer to computer using network, mail and other informational channels. Thanks to it spreading speed of worms is very high.

Worms intrude your computer, calculate network addresses of other computers and send to these addresses its copies. Besides network addresses, the data of the mail clients' address books is used as well. Representatives of this Malware type sometimes create working files on system discs, but may not deploy computer resources (except the operating memory).

Trojans: programs that execute on infected computers unauthorized by user actions; i.e. depending on the conditions delete information on discs, make the system freeze, steal personal information, etc. this Malware type is not a virus in traditional understanding (i.e. does not infect other programs or data): Trojans cannot intrude the PC by themselves and are spread by violators as “useful” and necessary software. And still harm caused by Trojans is higher than of traditional virus attack.

Spyware: software that allows to collect data about a specific user or organization, who are not aware of it. You may not even guess about having spyware on your computer. As a rule the aim of spyware is to:

• Trace user's actions on computer
• Collect information about hard drive contents; it often means scanning some folders and system registry to make a list of software installed on the computer.
• Collect information about quality of connection, way of connecting, modem speed, etc.

Collecting information is not the main function of these programs, they also threat security. Minimum two known programs – Gator and eZula – allow violator not only collect information but also control the computer. Another example of spyware are programs embedded in the browser installed on the computer and retransfer traffic. You have definitely come across such programs, when inquiring one address of a web-site, another web-site was opened. One of the spyware is phishing- delivery.

Phishing is a mail delivery whose aim is to get from the user confidential financial information as a rule. Phishing is a form of a social engineering, characterized by attempts to fraudulently acquire sensitive information, such as passwords and credit card details, by masquerading as a trustworthy person or business in an apparently official electronic communication, such as an email or an instant message. The messages contain link to a deliberately false site where user is suggested to enter number of his/her credit card and other confidential information.

Adware: program code embedded to the software without user being aware of it to show advertising. As a rule adware is embedded in the software that is distributed free. Advertisement is in the working interface. Adware often gathers and transfer to its distributor personal information of the user.

Riskware: this software is not a virus, but contains in itself potential threat. By some conditions presence of such riskware on your PC puts your data at risk. To this software refer utilities of remote administration, programs that use Dial Up-connection and some others to connect with pay-per-minute internet sites.

Jokes: software that does not harm your computer but displays messages that this harm has already been caused, or is going to be caused on some conditions. This software often warns user about not existing danger, e.g. display messages about hard disc formatting (though no formatting is really happening), detect viruses in not infected files and etc.

Rootkit: these are utilities used to conceal malicious activity. They disguise Malware, to prevent from being detected by the antivirus applications. Rootkits can also modify operating system on the computer and substitute its main functions to disguise its presence and actions that violator makes on the infected computer.

Other malware: different programs that have been developed to create other Malware, organizing DoS-attacks on remote servers, intruding other computers, etc. Hack Tools, virus constructors and other refer to such programs.

Spam: anonymous, mass undesirable mail correspondence. Spam is political and propaganda delivery, mails that ask to help somebody. Another category of spam are messages suggesting you to cash a great sum of money or inviting you to financial pyramids, and mails that steal passwords and credit card number, messages suggesting to send them to your friends (messages of happiness), etc. spam increases load on mail servers and increases the risk lose information that is important for the user.

If you suspect that your computer is infected with viruses, we recommend you:

• Install a trial version of a Kaspersky Lab product, update databases ans run full computer scan.
• Use free utility Kaspersky Virus Removal Tool 2011.

About viruses: General signs of a malware infection

There is a number of signs or symptoms indicating that your computer is infected. If you have started to notice weird things happening on your PC, such as:

• unusual messages, images, or sound signals;
• CD-ROM tray opens and closes voluntary;
• programs start running without your command;
• messages are displayed informing that one of your programs is attempting to access Internet without your command.

then it is likely that your computer is infected with malware.

Additional signs of email infections:

• Your friends or colleagues tell you about having received emails sent from your email box which you did not send;
• A lot of messages without a sender address and subject in your mailbox.
• It must be admitted that such signs are not always explained by presence of malware. They may have some other explanation. For example, the issue with weird emails may be the result of somebody sending infected emails with your sender address from some other computer, not necessarily yours.

There are also indirect signs of a malware infection on your computer:

• your PC frequently crashes or hangs;
• everything slows down when starting a program;
• operating system does not boot;
• missing or corrupt files and folders;
• excessive hard drive activity (the light on the front of the case flashes frequently);
• something is wrong with Microsoft Internet Explorer (it freezes or does not respond to commands, e.g.).

In 90% of cases, these indirect signs are caused by incorrect functioning of some hardware or software. Still, such signs have a little chance of being caused by an infection. If you experience any signs of this type, it is recommended to:

• Install a trial version of a Kaspersky Lab product, update anti-virus databases and run full computer scan.
• Use free utility Kaspersky Virus Removal Tool 2011.

About viruses: Viruses and solutions