Due to ever increasing threat from virus and other malicious programs, almost every computer today comes with a pre-installed antivirus software on it. In fact, an antivirus has become one of the most essential software package for every computer. Even though every one of us have an antivirus software installed on our computers, only a few really bother to understand how it actually works! Well if you are one among those few who would really bother to understand how an antivirus works, then this article is for you.

How Antivirus Works

An antivirus software typically uses a variety of strategies in detecting and removing viruses, worms and other malware programs. The following are the two most widely employed identification methods:

1. Signature-based dectection (Dictionary approach)

This is the most commonly employed method which involves searching for known patterns of virus within a given file. Every antivirus software will have a dictionary of sample malware codes called signatures in it’s database. Whenever a file is examined, the antivirus refers to the dictionary of sample codes present within it’s database and compares the same with the current file. If the piece of code within the file matches with the one in it’s dictionary then it is flagged and proper action is taken immediately so as to stop the virus from further replicating. The antivirus may choose to repair the file, quarantine or delete it permanently based on it’s potential risk. 

As new viruses and malwares are created and released every day, this method of detection cannot defend against new malwares unless their samples are collected and signatures are released by the antivirus software company. Some companies may also encourage the users to upload new viruses or variants, so that the virus can be analyzed and the signature can be added to the dictionary.

Signature based detection can be very effective, but requires frequent updates of the virus signature dictionary. Hence the users must update their antivirus software on a regular basis so as to defend against new threats that are released daily.

2. Heuristic-based detection (Suspicious behaviour approach)

Heuristic-based detection involves identifying suspicious behaviour from any given program which might indicate a potential risk. This approach is used by some of the sophisticated antivirus softwares to identify new malware and variants of known malware. Unlike the signature based approach, here the antivirus doesn’t attempt to identify known viruses, but instead monitors the behavior of all programs.

For example, malicious behaviours like a program trying to write data to an executable program is flagged and the user is alerted about this action. This method of detection gives an additional level of security from unidentified threats.

File emulation: This is another type of heuristic-based approach where a given program is executed in a virtual environment and the actions performed by it are logged. Based on the actions logged, the antivirus software can determine if the program is malicious or not and carry out necessary actions in order to clean the infection.

Most commercial antivirus softwares use a combination of both signature-based and heuristic-based approaches to combat malware.

Issues of concern

Zero-day threats: A zero-day (zero-hour ) threat or attack is where a malware tries to exploit computer application vulnerabilities that are yet unidentified by the antivirus software companies. These attacks are used to cause damage to the computer even before they are identified. Since patches are not yet released for these kind of new threats, they can easily manage to bypass the antivirus software and carry out malicious actions. However most of the threats are identified after a day or two of it’s release, but damage caused by them before identification is quite inevitable.

Daily Updates: Since new viruses and threats are released everyday, it is most essential to update the antivirus software so as to keep the virus definitions up-to-date. Most softwares will have an auto-update feature so that the virus definitions are updated whenever the computer is connected to the Internet.

Effectiveness: Even though an antivirus software can catch almost every malware, it is still not 100% foolproof against all kinds of threats. As explained earlier, a zero-day threat can easily bypass the protective shield of the antivirus software. Also virus authors have tried to stay a step ahead by writing “oligomorphic“, “polymorphic” and, more recently, “metamorphic” virus codes, which will encrypt parts of themselves or otherwise modify themselves as a method of disguise, so as to not match virus signatures in the dictionary.

Thus user education is as important as antivirus software; users must be trained to practice safe surfing habits such as downloading files only from trusted websites and not blindly executing a program that is unknown or obtained from an untrusted source. I hope this article will help you understand the working of an antivirus software.

How Firewalls Work

Firewalls are basically a barrier between your computer (or a network) and the Internet (outside world). A firewall can be simply compared to a security guard who stands at the entrance of your house and filters the visitors coming to your place. He may allow some visitors to enter while denying others whom he suspects of being intruders. Similarly a firewall is a software program or a hardware device that filters the information (packets) coming through the Internet to your personal computer or a computer network.

Firewalls may decide to allow or block network traffic between devices based on the rules that are pre-configured or set by the firewall administrator. Most personal firewalls such as Windows firewall operate on a set of pre-configured rules that are most suitable under normal circumstances so that the user need not worry much about configuring the firewall.

Personal firewalls are easy to install and use and hence preferred by end-users for use on their personal computers.  However large networks and companies prefer those firewalls that have plenty of options to configure so as to meet their customized needs. For example, a company may set up different firewall rules for FTP servers, Telnet servers and Web servers. In addition the company can even control how the employees connect to the Internet by blocking access to certain websites or restricting the transfer of files to other networks. Thus in addition to security, a firewall can give the company a tremendous control over how people use the network.

Firewalls use one or more of the following methods to control the incoming and outgoing traffic in a network:

1. Packet Filtering: In this method packets (small chunks of data) are analyzed against a set of filters. Packet filters has a set of rules that come with accept and deny actions which are pre-configured or can be configured manually by the firewall administrator. If the packet manages to make it through these filters then it is allowed to reach the destination; otherwise it is discarded.

2. Stateful Inspection: This is a newer method that doesn’t analyze the contents of the packets. Instead it compares certain key aspects of each packet to a database of trusted source. Both incoming and outgoing packets are compared against this database and if the comparison yields a reasonable match, then the packets are allowed to travel further. Otherwise they are discarded.

Firewall Configuration

Firewalls can be configured by adding one or more filters based on several conditions as mentioned below:

1. IP addresses: In any case if an IP address outside the network is said to be unfavorable, then it is possible to set  filter to block all the traffic to and from that IP address. For example, if a cetain IP address is found to be making too many connections to a server, the administrator may decide to block traffic from this IP using the firewall.

2. Domain names: Since it is difficult to remember the IP addresses, it is an easier and smarter way to configure the firewalls by adding filters based on domain names. By setting up a domain filter, a company may decide to block all access to certain domain names, or may provide access only to a list of selected domain names.

3. Ports/Protocols: Every service running on a server is made available to the Internet using numbered ports, one for each service. In simple words, ports can be compared to virtual doors of the server through which services are made available. For example, if a server is running a Web (HTTP) service then it will be typically available on port 80. In order to avail this service, the client needs to connect to the server via port 80. Similarly different services such as Telnet (Port 23), FTP (port 21) and SMTP (port 25) services may be running on the server. If the services are intended for the public, they are usually kept open. Otherwise they are blocked using the firewall so as to prevent intruders from using the open ports for making unauthorized connections.

4. Specific words or phrases: A firewall can be configured to filter one or more specific words or phrases so that, both the incoming and outgoing packets are scanned for the words in the filter. For example, you may set up a firewall rule to filter any packet that contains an offensive term or a phrase that you may decide to block from entering or leaving your network.

Hardware vs. Software Firewall

Hardware firewalls provide higher level of security and hence preferred for servers where security has the top most priority whereas, the software firewalls are less expensive and are most preferred in home computers and laptops. Hardware firewalls usually come as an in-built unit of a router and provide maximum security as it filters each packet in the hardware level itself even before it manages to enter your computer. A good example is the Linksys Cable/DSL router.

Why Firewall?

Firewalls provide security over a number of online threats such as Remote login, Trojan backdoors, Session hijacking, DOS & DDOS attacks, viruses, cookie stealing and many more. The effectiveness of the security depends on the way you configure the firewall and how you set up the filter rules. However major threats such as DOS and DDOS attacks may sometimes manage to bypass the firewalls and do the damage to the server. Even though firewall is not a complete answer to online threats, it can most effectively handle the attacks and provide security to the computer up to the maximum possible extent.

Use a Good Antivirus

This is the first and basic step that you need to take in order to protect your computer from keyloggers. Use a Good antivirus such as Kaspersky, Norton or Mcafee and update it regularly.

Use a Good Antispyware

Since keyloggers are basically spywares, if you are a frequent user of Internet then you could be exposed to thousands of keyloggers and spywares. So you should use a good antispyware such as NoAdware.

Antilogger can be Handy

Antiloggers are programs that detect the presence of keyloggers on a given computer. Over past few years, I have tested a lot of anti-logging programs and have found Zemana Antilogger as the best antilogger.

Zemana

Normally a keylogger can be easily detected by a Good Antivirus program, but hackers use some methods such as hexing, binding, crypting and similar techniques to make it harder to be detected by antivirus programs. In this case Zemana Antilogger comes handy as the program is specially developed to protect your system against harmful keyloggers.

Online Scanning

When ever you receive a suspicious file, you scan it with online scanners such as Multi engine antivirus scanner which scans your file with 24 antivirus engines and reports it back to you if the file is recognized as a virus or spyware. This ensures that none of the malicious programs can escape from being detected as there are 24 different antivirus engines are involved in the scanning process.

Sandboxie

Sandboxie is another great program to help you protect your computer against harmful keyloggers and spywares. Sandboxie runs your computer in an isolated space which prevents your program from making permanent changes to other programs in your computer.

When ever you receive a file that looks suspicious, just run the program with Sandboxie so even if it is a keylogger or any other virus it will not make permanent changes to your computer system.

To run a program in Sandboxie follow the steps as mentioned below:

1. Open sandboxie and click on sandbox menu on the top

2. Now goto Default sandbox

3. Then click on run any program

4. Now select the file you wish to run in sandboxie and click open

Keyscrambler

Keyscrambler is one of the best protection against keyloggers that you can have, Keyscrambler is a small program which encrypts your typed keystrokes so even if the victim has installed a keylogger on your system, he or she will get encrypted keys. Keyscrambler currently supports Firefox, Internet explorer and other applications, however its premium version supports more than 160 applications.

Hope you liked my post! Pass the comments.

Adware, malware, spyware and viruses can bring your system to its knees. They are detrimental, lowering the performance of your computer. You might need to replace data. You might lose unique files. Keep the nasties away from your computer using these ten simple tips.

1. Use Firefox: Internet Explorer is the most popular browser on the market, controlling over 50% of the market share. The virus and adware creators specifically look for exploitable vulnerabilities within IE because they know that they will receive the best return on investment. Your switch to Firefox prevents some adware from infecting your machine.

2. Scan your PC once a week: Sometimes adware programmers take a sneaky approach. They will set up their programs to run quietly in the background to spy upon your activities. This once a week scan is necessary to remove any of those sneaky bugs.

3. Download from known sites: New sites for installing adware are popping up all the time. If you find something that you want to download, make sure that it is from a known site. A company like Amazon will not steer you wrong, but Bob’s House of Wares might be a little less trustable. If you are not sure whether you can trust a site, perform a quick search.

4. Install Adaware: Ad-Aware is the most popular free adware removal program on the market. It detects, quarantines and removes adware. It searches for other programs which may have been installed, highlighting them in an easy to use interface. This program does not have an anti-virus attached.

5. Do not click on unsolicited email: You are constantly receiving offers to increase this or improve that through unsolicited email. Your curiosity may be killing you, but don’t click on these emails. They accept your click as permission to install adware, spyware and malware on your PC.

6. Install Antivirus software: Installing two programs for virus and adware protection is a smart idea. It caters to the strengths of each program, increasing the overall strength of your antiadware and antiviral campaign. Some of the best antivirus software is free, providing real time protection. Programs to look at would be Avast Antivir and AVG.

7. Don’t install toolbars: Even some reputable sites install custom toolbars. They slow your system down and collect information about your surfing habits. While a toolbar might offer some perks, it may also diminish your experience by dragging your system to a halt. Toolbars from less reputable places install adware and sometimes infect your system outright.

8. Look at your task manager: If anything seems out of place with your computer, take a look at your task manager. This tells you about all of the programs and processes which are running on your computer. Examine the processes tab for anything which you don’t immediately recognize. Perform a web search for unfamiliar processes.

9. Do not click on popups: Clicking on a popup usually spells certain doom for your computer. It opens the door for the viruses and adware that want to infect your machine, telling these malicious applications to make themselves at home. Stay away from those constantly advertised screensavers and icons.

10. Trust your gut: If you don’t feel right about a site, don’t go there. If you are receiving warnings from the antivirus and antiadware programs which you’ve installed, don’t go there. If you don’t like the layout of a site, don’t go there. Trust your instincts about sites.

With proper vigilance, you can keep aggravating adware, spyware and malware from your machine. Trust your instincts. Install Ad-Aware and an antivirus program. Play it safe. The care you spend in preventing adware from infecting your machine can save money and time.

1. Open a notepad (New Text Document.TXT) and copy the following code exactly onto it, and save the notepad.

EICAR Test code
X5O!P%@AP[4\PZX54(P^)7CC)7}$EICAR-STANDARD-ANTIVIRUS-TEST-FILE!$H+H*

2. Rename the file from New Text Document.TXT to myfile.com

3. Now run the antivirus scan on this myfile.com file.

If the antivirus is functioning properly on your computer, then it should generate a warning and immediately delete the file upon scanning. Otherwise you may have to re-install your antivirus.

You can also place the myfile.com file in a ZIP or RAR file and run a scan on it so as to ensure whether your antivirus can detect the test string in the compressed archive. Any antivirus when scanning this file will respond exactly as it will do for a genuine virus/malicious code. This test will cause no damage to your computer even though the antivirus will flag it as a malicious script. Hence it is the safest method to test the proper functioning of any antivirus.

1. Always install a good antivirus software and keep it up-to-date. Also install a good anti-spyware to keep your PC away from spywares. Click Here for a list of recommended anti-spyware softwares.

2. Always visit known and trusted websites. If you are about to visit an unknown website, ensure that you do not click on suspectable links and banners.

3. Perform a virus scan on the files/email attachments that you download before executing them.

4. Regularly Update your operating system and browser software. For a better security it is recommended that you surf the Internet through the latest version of your browser program.

5. Never share your password (email, bank logins etc.) with any one for any reason. Choose a strong password (A blend of alphanumeric+special symbols) and change it regularly, eg. every 3 months. Avoid using easy-to-guess passwords. (ex. pet’s name or kid’s name)

6. Always type the URL of the website in your browser’s address bar to enter the login pages. For ex. To login to your Gmail account type http://mail.google.com 

7. Before you enter your password on any login page, ensure that you see https instead of http. ex. https://mail.google.com instead of http://mail.google.com. HTTPS protocol implements SSL (Secure Sockets Layer) and provide better security than a normal HTTP. For more information on HTTPS and SSL see Know More About Secure Sockets Layer (SSL).

8. Beware of phishing emails! Do not respond to any email that request you to update your login details by clicking on a link in the body of the email. Such links can lead to Fake Login Pages (Spoofed Pages). For more information on phishing refer What is Phishing?. Also refer How to Protect an Email Account from being Hacked.

9. Always hit the logout button to close your login session rather than abruptly terminating the browser window. Also clear your web browser caches after every session to remove the temporary files stored in the memory and hard disk of your PC.

10. Avoid (Stop) using any public computers or computers in the Internet cafes to access any sensitive/confidential information. Also avoid such computers to login to your email/bank accounts. You cannot be sure if any spyware, keystroke-logger, password-sniffer and other malicious programs have not been installed on such a PC.

By following the above 10 tips your online security can be guaranteed upto 90%. I hope this will help my readers for keeping themselves safe from any of the online insecurities. Cheers! Pass your comments.

1. Phishing Scam

This is one of the most commonly used scam to steal bank logins and other types of passwords on the Internet. Phishing is the criminally fraudulent process of attempting to acquire sensitive information such as usernames, passwords and credit card details by masquerading as a trustworthy entity in an electronic communication. Phishing is typically carried out by e-mail or instant messaging.

Example:You may receive an email which claims to have come from your bank/financial institution/online service provider that asks you to click a link and update your account information. When you click such a link it will take you to a fake page which exactly resembles the original ones. Here you’ll be asked to enter your personal details such as username and password. Once you enter your personal details they will be stolen away. Such an email is more than likely the type of Internet scam known as “phishing”. Phishing is said to be highly effective and has proved to have more success rate since most of the common people fail to identify the scam.

Most legitimate companies never request any kind of personal/sensitive information via email. So it is highly recommended that you DO NOT respond to such fraudulent emails. For more information on phishing visit my detailed post What is Phishing?

2. Nigerian Scams

This type of scam involves sending emails (spam) to people in bulk seeking their help to access large amount of money that is held up in a foreign bank account. This email claims that in return for the help you’ll be rewarded a percentage of the fund that involves in the transaction. Never respond to these emails since it’s none other than a scam.

In case if you respond to these emails you will be asked to deposit a small amount of money (say 1-2% of the whole fund) as an insurance or as an advance payment for the initialization of deal. However once you deposit the amount to the scammer’s account you’ll not get any further response from them and you lose your money. In fact “The large amount of money” never exists and the whole story is a trap for innocent people who are likely to become victims. The scammers use a variety of stories to explain why they need your help to access the funds. The following are some of the examples of them.

Examples:

• They may claim that political climate or legal issues preclude them from accessing funds in a foreign bank account
• They may claim that the person is a minor and hence needs your help to access the funds
• They may claim that your last name is the same as that of the deceased person who owned the account and suggest that you act as the Next of Kin of this person in order to gain access to the funds

3. Lottery Scams

This type of scam is similar to the one discussed above. In this type you may receive an email saying that you have won a large sum of money in online lottery scheme (ex. UK Lottery) even though you have not participated in any such schemes. The message claims that your email ID was selected randomly from a lagre pool of IDs. When you respond to such emails they initially ask for your complete name and address so that they can mail the cheque accross to you. After getting those details they may also send you an image of the cheque drawn in your name and address so as to confirm the deal. But in order to mail this cheque they demand a small amount of money as insurance/shipping charge/tax in return. However if you send the amount in hope to receive the cheque all you get is nothing. You’re just trapped in a wonderful scam scheme. Thats it.

4. Other General Scams and Frauds

The following are some of the other types of scams that you should be aware of.

In general, be aware of unsolicited emails that:

1. Promise you money, jobs or prizes
2. Ask you to provide sensitive personal information
3. Ask you to follow a link to a website and log on to an account.
4. Propose lucrative business deals

However it may seem to be a difficult task for novice Internet users to identify such online scams. Here are some of the common signs of such scam emails. By knowing them it may help you to stay away.

• All these scam emails never address you by your name. In turn they commonly address you something like “Dear User” or “Dear Customer” etc. This is a clear indication that the email is a fraudulent one
• When you observe the email header you may notice in the “TO:” Field that, the same email is forwarded to a large group of people or the “TO:” field appears blank. So this confirms that the email was not intended particularly for you. It was forwarded for a large group of people and you are one among them

I hope this post helps. Express your opinions through comments.

1. Email is one of the common ways by which your computer can catch a virus. So it is always recommended to stay away from SPAM. Open only those emails that has it’s origin from a trusted source such as those which comes from your contact list. If you are using your own private email host (other than gmail, yahoo, hotmail etc.) then it is highly recommended that you use a good anti-spam software. And finally NEVER click on any links in the emails that comes from untrusted sources.

2. USB thumb/pen drives is another common way by which viruses spread rapidly. So it is always a good habit to perform a virus scan before copying any data onto your computer. NEVER double-click the pen drive to open it. Instead right-click on it and select the option “open”. This is a safe way to open a pen drive. 

3. Be careful about using MS Outlook. Outlook is more susceptible to worms than other e-mail programs, unless you have efficient Anti-Virus programs running. Use Pegasus or Thunderbird (by Mozilla), or a web-based program such as Hotmail or Yahoo (In Firefox).

4. As we all know, Internet is the main source of all the malicious programs including viruses, worms, trojans etc. In fact Internet contributes to virus infection by up to 80%. So here are the tips for safe surfing habits so that you can ward off virus infection up to the maximum extent.

• Don’t click on pop-up windows that announce a sudden disaster in your city or announce that you’ve won an hourly prize. They are the ways to mislead Internet users and you should never trust them.
• You can also use a pop-up blocker to automatically block those pop-ups.

5. Most of us use search engines like Google to find what we are looking for. It is quite obvious for a malicious website to get listed in the search results. So to avoid visiting those untrusted malicious websites, you can download and install the AVG LinkScanner which is a freeware. This tool can become very handy and will help you to stay away from malicious websites.

6. Install a good antivirus software and keep it updated. Also perform full system scan periodically. It is highly recommended that you turn on the automatic update feature. This is the most essential task to protect your PC from virues. If PC security is your first option then it is recommended that you go for a shareware antivirus software over the free ones. Most of the antivirus supports the Auto-Protect feature that provides realtime security for your PC. Make sure that this feature is turned on.

7. Install a good Antispyware program, that operates against Internet malware and spyware.

8. Never open any email attachments that come from untrusted sources. If it is a picture, text or sound file (these attachments end in the extensions .txt, .jpeg, .gif, .bmp, .tif, .mp3, .htm, .html, and .avi), you are probably safe, but still do a scan before opening.

9. Do not use disks that other people gave you, even from work. The disk could be infected with a virus. Of course, you can run a virus scan on it first to check it out.

10. Set up your Windows Update to automatically download patches and upgrades. This will allow your computer to automatically download any updates to both the operating system and Internet Explorer. These updates fix security holes in both pieces of software.

11. While you download files from untrusted websites/sources such as torrents, warez etc. make sure that you run a virus scan before executing them.

12. And finally it is recommended not to visit the websites that feature illegal/unwanted stuffs such as cracks, serials, warez etc. since they contribute much in spreading of viruses and other malicious programs.