The New meaning of P2P

I am writing this article to encourage the budding engineers out there to take concrete and meaningful steps to address the serious risks posed to our culture and to the entire humanity by today’s peer-to-peer (“P2P”) file-sharing technology. My concern here is to address issues relating problems of today as the use of P2P Networks to disseminate pornography invade privacy and infringe copyrights, P2P software may one day realize its potential as a means for facilitating a wide range of collaborative, project management, business planning, and academic/education activities. At present, P2P software has too many times been hijacked by those who use it for illegal purposes to which the vast majority of today’s computer users do not wish to be exposed.

The users need to be provided with the information necessary to understand this Technology and to make informed decisions concerning its use. P2P file-sharing technology works by allowing consumers to download free software that enables them to directly share files stored on their hard drive with other users. This type of direct access to one’s computer differentiates P2P file-sharing technology from garden-variety e-mail accounts and commercial search engines such as Google and Yahoo.

One substantial and ever-growing use of P2P software is as a method of disseminating Pornography, including child pornography. While at least some of today’s so called top companies do provide “filters” to help screen out unwanted files, including presumably those containing pornography, those filters appear to work by focusing on language in the file’s description or the file’s title rather than on the file’s content. P2P users interested in disseminating and receiving offensive or illegal material, such as child pornography, can simply use an innocuous file title and/or description in order to bypass those filters. Consequently, P2P users need to be made aware that they are exposing themselves, and their children, to widespread availability of pornographic material when they download and install P2P file-sharing programs on their computers.

Furthermore, P2P file-sharing technology can allow its users to access the files of other Users, even when the computer is “off” if the computer itself is connected to the Internet via Broadband. P2P users, including both home users and small businesses, who do not properly understand this software have inadvertently given other P2P users access to tax returns, medical files, financial records, personal e- mail, and confidential documents stored on their computers. Combating identity theft is the main priority , and government of our country has enacted slow motion laws to stop it. Consequently, P2P users need to be properly educated so that they will not inadvertently share personal files on their hard drives with other users of your P2P file-sharing technology.

P2P file-sharing programs also are being used to illegally trade copyrighted music, movies, software, and video games, contributing to economic losses. Being quite a download freak myself I gave up P2P for downloading movies and other copyrighted material after I hitting a massive ONE TERABYTE download. The Business Software Alliance estimates that its members lost $13 billion in revenue last year due to software piracy. According to a January 2007 CNN article, “U.S. software companies lose up to $170 billion a year in piracy according to the Software and Information Industry Association. Music companies lost more than $46 billion worldwide last year, according to the RIAA [Recording Industry Association of America] ”.

Also viewing the reports that P2P software is being used as a means of transmitting unwanted spyware and adware that is bundled with the P2P software. Spyware aids an individual or a corporation in gathering information about P2P users without their consent or in asserting control over P2P users’ computers without their consent. We hope that at least some P2P file-sharing services add encryption features to those services. The addition of such encryption features will make it more difficult, if not impossible, for law enforcement to police users of P2P technology in order to prosecute crimes such as child pornography. Encryption only reinforces the perception that P2P technology is being used primarily for illegal ends.

Every time a new communications medium is presented, pornography and erotica seem to be distributed using it. Unfortunately, we live in times in which there are people in positions of political and legal influence who believe that they should be able to define what is and is not proper, and furthermore restrict access to that material. We have also heard of cases in which people have had their computers confiscated for having a computer image on disk, which they were unaware was present, that depicted activities that someone decided violated "community standards." There have also been cases where individuals have been convicted of pornography charges, even though the material was not considered obscene where the system was normally accessed. And last of all, you can be in serious legal trouble for simply FTPing an image of a naked minor, even if you don't know what is in the image at the time you fetch it.

We should also point out that as part of any sensible security administration, you should know what you have on your computer, and why. Keep track of who is accessing material you provide, and beware of unauthorized use.

And on an ending note I would like to say that it is the duty of today’s youth to see to that the technology is not misused because it will take us in the direction we want it to go.

please step forward to put an end to this ...
ajay

Dummies guide to Strong passwords: How to create and use them


Your passwords are the keys you use to access personal information that you've stored on your computer and in your online accounts. If criminals or other malicious users steal this information, they can use your name to open new credit card accounts, apply for a mortgage, or pose as you in online transactions. In many cases you would not notice these attacks until it was too late.
Fortunately, it is not hard to create strong passwords and keep them well protected.

What makes a strong password???

To an attacker, a strong password should appear to be a random string of characters. The following criteria can help your passwords do so:

Make it lengthy. Each character that you add to your password increases the protection that it provides many times over. Your passwords should be 8 or more characters in length; 14 characters or longer is ideal.

Many systems also support use of the space bar in passwords, so you can create a phrase made of many words (a "pass phrase"). A pass phrase is often easier to remember than a simple password, as well as longer and harder to guess.

Combine letters, numbers, and symbols. The greater variety of characters that you have in your password, the harder it is to guess. Other important specifics include:

The fewer types of characters in your password, the longer it must be. A 15-character password composed only of random letters and numbers is about 33,000 times stronger than an 8-character password composed of characters from the entire keyboard. If you cannot create a password that contains symbols, you need to make it considerably longer to get the same degree of protection. An ideal password combines both length and different types of symbols.
Use the entire keyboard, not just the most common characters. Symbols typed by holding down the "Shift" key and typing a number are very common in passwords. Your password will be much stronger if you choose from all the symbols on the keyboard, including punctuation marks not on the upper row of the keyboard, and any symbols unique to your language.

Use words and phrases that are easy for you to remember, but difficult for others to guess. The easiest way to remember your passwords and pass phrases is to write them down. Contrary to popular belief, there is nothing wrong with writing passwords down, but they need to be adequately protected in order to remain secure and effective.

In general, passwords written on a piece of paper are more difficult to compromise across the Internet than a password manager, Web site, or other software-based storage tool, such as password managers.
Create a strong, memorable password in 6 steps

Use these steps to develop a strong password:

1. Think of a sentence that you can remember. This will be the basis of your strong password or pass phrase. Use a memorable sentence, such as "My son Aiden is three years old."

2. Check if the computer or online system supports the pass phrase directly. If you can use a pass phrase (with spaces between characters) on your computer or online system, do so.

3. If the computer or online system does not support pass phrases, convert it to a password. Take the first letter of each word of the sentence that you've created to create a new, nonsensical word. Using the example above, you'd get: "msaityo".

4. Add complexity by mixing uppercase and lowercase letters and numbers. It is valuable to use some letter swapping or misspellings as well. For instance, in the pass phrase above, consider misspelling Aiden's name, or substituting the word "three" for the number 3. There are many possible substitutions, and the longer the sentence, the more complex your password can be. Your pass phrase might become "My SoN Ayd3N is 3 yeeRs old." If the computer or online system will not support a pass phrase, use the same technique on the shorter password. This might yield a password like "MsAy3yo".

5. Finally, substitute some special characters. You can use symbols that look like letters, combine words (remove spaces) and other ways to make the password more complex. Using these tricks, we create a pass phrase of "MySoN 8N i$ 3 yeeR$ old" or a password (using the first letter of each word) "M$8ni3y0".

6. Test your new password with Password Checker. Password Checker is a non-recording feature on this Web site that helps determine your password's strength as you type.

Password strategies to avoid

Some common methods used to create passwords are easy to guess by criminals. To avoid weak, easy-to-guess passwords:

• Avoid sequences or repeated characters. "12345678," "222222," "abcdefg," or adjacent letters on your keyboard do not help make secure passwords.

• Avoid using only look-alike substitutions of numbers or symbols. Criminals and other malicious users who know enough to try and crack your password will not be fooled by common look-alike replacements, such as to replace an 'i' with a '1' or an 'a' with '@' as in "M1cr0$0ft" or "P@ssw0rd". But these substitutions can be effective when combined with other measures, such as length, misspellings, or variations in case, to improve the strength of your password.

• Avoid your login name. Any part of your name, birthday, social security number, or similar information for your loved ones constitutes a bad password choice. This is one of the first things criminals will try.

•Avoid dictionary words in any language. Criminals use sophisticated tools that can rapidly guess passwords that are based on words in multiple dictionaries, including words spelled backwards, common misspellings, and substitutions. This includes all sorts of profanity and any word you would not say in front of your children.

•Use more than one password everywhere. If any one of the computers or online systems using this password is compromised, all of your other information protected by that password should be considered compromised as well. It is critical to use different passwords for different systems.

•Avoid using online storage. If malicious users find these passwords stored online or on a networked computer, they have access to all your information.

The "blank password" option

A blank password (no password at all) on your account is more secure than a weak password such as "1234". Criminals can easily guess a simplistic password, but on computers using Windows XP, an account without a password cannot be accessed remotely by means such as a network or the Internet. (This option is not available for Microsoft Windows 2000, Windows Me, or earlier versions) You can choose to use a blank password on your computer account if these criteria are met:

• You only have one computer or you have several computers but you do not need to access information on one computer from another one .

• The computer is physically secure (you trust everyone who has physical access to the computer) The use of a blank password is not always a good idea. For example, a laptop computer that you take with you is probably not physically secure, so on those you should have a strong password.

How to access and change your passwords

Online accounts

Web sites have a variety of policies that govern how you can access your account and change your password. Look for a link (such as "my account") somewhere on the site's home page that goes to a special area of the site that allows password and account management.

Computer passwords
The Help files for your computer operating system will usually provide information about how to create, modify, and access password-protected user accounts, as well as how to require password protection upon startup of your computer. You can also try to find this information online at the software manufacturer's Web site. For example, if you use Microsoft Windows XP, online help can show you how to manage passwords, change passwords, and more.

Keep your passwords secret

Treat your passwords and pass phrases with as much care as the information that they protect.

• Don't reveal them to others. Keep your passwords hidden from friends or family members (especially children) who could pass them on to other less trustworthy individuals. Passwords that you need to share with others, such as the password to your online banking account that you might share with your spouse, are the only exceptions.

• Protect any recorded passwords. Be careful where you store the passwords that you record or write down. Do not leave these records of your passwords anywhere that you would not leave the information that they protect.

• Never provide your password over e-mail or based on an e-mail request. Any e-mail that requests your password or requests that you to go to a Web site to verify your password is almost certainly a fraud. This includes requests from a trusted company or individual. E-mail can be intercepted in transit, and e-mail that requests information might not be from the sender it claims. Internet "phishing" scams use fraudulent e-mail messages to entice you into revealing your user names and passwords, steal your identity, and more. Learn more about phishing scams and how to deal with online fraud.

• Change your passwords regularly. This can help keep criminals and other malicious users unaware. The strength of your password will help keep it good for a longer time. A password that is shorter than 8 characters should be considered only good for a week or so, while a password that is 14 characters or longer (and follows the other rules outlined above) can be good for several years.

• Do not type passwords on computers that you do not control. Computers such as those in Internet cafés, computer labs, shared systems, kiosk systems, conferences, and airport lounges should be considered unsafe for any personal use other than anonymous Internet browsing. Do not use these computers to check online e-mail, chat rooms, bank balances, business mail, or any other account that requires a user name and password. Criminals can purchase keystroke logging devices for very little money and they take only a few moments to install. These devices let malicious users harvest all the information typed on a computer from across the Internet—your passwords and pass phrases are worth as much as the information that they protect.

What to do if your password is stolen

Be sure to monitor all the information you protect with your passwords, such as your monthly financial statements, credit reports, online shopping accounts, and so on. Strong, memorable passwords can help protect you against fraud and identity theft, but there are no guarantees. No matter how strong your password is, if someone breaks into the system that stores it, they will have your password. If you notice any suspicious activity that could indicate that someone has accessed your information, notify authorities as quickly as you can. Get more information on what to do if you think your identity has been stolen or you've been similarly defrauded.

The Password Management Problem

It's that time again. You've been asked to change the password that gives you access to all your crucial systems and information. Or perhaps you need to enter yet another new password to access yet another application, document, or system.

Choosing Hard to Guess Passwords

It's tempting to pick something easy to remember, like spelling your user name backwards, or child's name, or a word from the dictionary. The problem is, the easier it is to remember, the easier it is for an intruder to steal.

Malicious intruders often gain access to a company's systems by stealing, or cracking, a password and account name, then posing as that user. If the intruder knows you, they can easily gain access by trying password combinations related to your family or hobbies. If they have physical access to your desk or digital assistant, their chances of getting into your accounts are even greater if you've used something personal for your password.

Hackers use readily available software to rapidly enter random dictionary words until they hit pay dirt, and it can take only minutes! The shorter the password, the faster it can be guessed. Even words spelled backwards, rearranged, or including numbers are not safe. A common misconception is that substitutions, such as replacing the letter l or i with the digit 1 will fool password cracking software. Password cracking programs are smart enough to do this too.

Examples of bad passwords include:

mydog2
bi11smith
yromem (memory backwards)
win4me
The safest solution for choosing good passwords is to use a randomly generated or seemingly random password that:
Is at least 6 characters long, and longer if possible.
Contains a mix of upper and lower case letters.
Includes numerals, special characters, and punctuation.
Is not based on any personal information.
Is not based on any dictionary word.
Examples of strong passwords include:

De2#vu
5sd$oiP
er89TI

Writing Down Passwords

If you have too many passwords, it is tempting to write them down -- after all, can you really remember 10 different passwords, that change at different times, some of which are rarely used?
Writing down passwords is a serious breach of security, because it means that anyone who can physically get to the piece of paper, sticky note or PDA that contains the password, can also log into systems with your accounts. Should a visiting vendor really be able to sign into the finance application? Should the janitor be able to read your mail?

A better solution is to create a single, strong password, and apply it to all of your login accounts. One password is easier to remember, and is more secure than a post-it note.

Reusing Passwords

Another temptation, when imagination fails, is to reuse old password values when the time comes to change your password. This is also a security problem, since the whole point of a regular password change is to limit the time available to an intruder to crack your password. If an old password is reused, intruders would have more time to crack them. If the old password was already compromised, the new one will compromise your security again.

If you cannot think of a new, secure password -- have a program, like P-Synch®, randomly generate one for you.

How to Choose a Good Password

Some security experts recommend using a password based on a mnemonic, such as an easily remembered phrase. For example, take the first letter of a each word in a phrase, then add a few special characters or numbers to it. For example, "lend me your ears" can become "lmye4%". "To be or not to be, that is the question" can become "2Bor!2b?".

This is good technique, but you may need some patience to think up a new phrase every time you change your password -- especially if you have to think of a different password for every system that you log into. This may lead some users to recycle some version of their old password - another security threat.

Another easy way to choose a good, safe password is to let an application like P-Synch do it for you. P-Synch makes remembering passwords easy by synchronizing passwords, so that you only have one password to remember, and that password works on every system.

P-Synch can provide a suggested list of randomly generated passwords, and reject passwords that do not comply with strong password rules, so that you always choose good passwords.

When to Change Your Password

Perhaps just as important as how to choose a new password is when to do it. New passwords are most easily remembered if you start using them immediately, and use them often. Don't change your password at the end of the day, the end of the week, or before a holiday. Instead, change your password in the morning, at the start of the week. Your mind will be clearer, and frequent use of the new password will reinforce your memory.

if you need any more information regarding this topic , feel free to mail me at my email address or drop in your comments here on my blog.
regards....
ajay

Network Security Via Reverse Engineering of TCP Code:

The Transmission Control Protocol/Internet Protocol (TCP/IP ) suite is a very widely used technique that is employed to interconnect computing facilities in modern network environments. However, there exist several security vulnerabilities in the TCP specification and additional weaknesses in a number of widely-available implementations of TCP. These vulnerabilities may enable an intruder to attack TCP-based systems, enabling him/her to hijack a TCP connection or cause denial of service to legitimate users. The analysis of TCP code via a reverse engineering" technique called slicing to identify several of these vulnerabilities, especially those that are related to the TCP state-transition diagram.

Now here rather than telling how intrusion dectection works , i'm going to be writing a series of FAQ's about The Process :

1.1 What is a "network intrusion detection system (NIDS)"?

An intrusion is somebody (A.K.A. "hacker" or "cracker") attempting to break into or misuse your system. The word "misuse" is broad, and can reflect something severe as stealing confidential data to something minor such as misusing your email system for spam (though for many of us, that is a major issue!).

An "Intrusion Detection System (IDS)" is a system for detecting such intrusions. For the purposes of this FAQ, IDS can be broken down into the following categories:

network intrusion detection systems (NIDS) monitors packets on the network wire and attempts to discover if a hacker/cracker is attempting to break into a system (or cause a denial of service attack). A typical example is a system that watches for large number of TCP connection requests (SYN) to many different ports on a target machine, thus discovering if someone is attempting a TCP port scan. A NIDS may run either on the target machine who watches its own traffic (usually integrated with the stack and services themselves), or on an independent machine promiscuously watching all network traffic (hub, router, probe). Note that a "network" IDS monitors many machines, whereas the others monitor only a single machine (the one they are installed on).

system integrity verifiers (SIV) monitors system files to find when a intruder changes them (thereby leaving behind a backdoor). The most famous of such systems is "Tripwire". A SIV may watch other components as well, such as the Windows registry and chron configuration, in order to find well known signatures. It may also detect when a normal user somehow acquires root/administrator level privleges. Many existing products in this area should be considered more "tools" than complete "systems": i.e. something like "Tripwire" detects changes in critical system components, but doesn't generate real-time alerts upon an intrusion.

log file monitors (LFM) monitor log files generated by network services. In a similar manner to NIDS, these systems look for patterns in the log files that suggest an intruder is attacking. A typical example would be a parser for HTTP server log files that looking for intruders who try well-known security holes, such as the "phf" attack. Example: swatch

Deception systems (A.K.A. decoys, lures, fly-traps, honeypots) which contain pseudo-services whose goal is to emulate well-known holes in order to trap hackers. Also, simple tricks by renaming "administrator" account on NT, then setting up a dummy account with no rights by extensive auditing can be used.

1.2 Who is misusing the system?

There are two words to describe the intruder: hacker and cracker. A hacker is a generic term for a person who likes getting into things. The benign hacker is the person who likes to get into his/her own computer and understand how it works. The malicious hacker is the person who likes getting into other people's systems. The benign hackers wish that the media would stop bad-mouthing all hackers and use the term 'cracker' instead. Unfortunately, this is not likely to happen. In any event, the word used in this FAQ is 'intruder', to generically denote anybody trying to get into your systems.

Intruders can be classified into two categories:
Outsiders
Intruders from outside your network, and who may attack you external presence (deface web servers, forward spam through e-mail servers, etc.). They may also attempt to go around the firewall to attack machines on the internal network. Outside intruders may come from the Internet, dial-up lines, physical break-ins, or from partner (vendor, customer, reseller, etc.) network that is linked to your corporate network.
Insiders
Intruders that legitimately use your internal network. These include users who misuse privileges (such as the Social Security employee who marked someone as being dead because they didn't like that person) or who impersonate higher privileged users (such as using someone else's terminal). A frequently quoted statistic is that 80% of security breaches are committed by insiders.

There are several types of intruders Joy riders hack because they can. Vandals are intent on causing destruction or marking up your web-pages. Profiteers are intent on profiting from their enterprise, such as rigging the system to give them money or by stealing corporate data and selling it.

1.3 How do intruders get into systems?

The primary ways a intruder can get into a system:

Physical Intrusion If a intruders have physical access to a machine (i.e. they can use the keyboard or take apart the system), they will be able to get in. Techniques range from special privileges the console has, to the ability to physically take apart the system and remove the disk drive (and read/write it on another machine). Even BIOS protection is easy to bypass: virtually all BIOSes have backdoor passwords.

System Intrusion This type of hacking assumes the intruder already has a low-privilege user account on the system. If the system doesn't have the latest security patches, there is a good chance the intruder will be able to use a known exploit in order to gain additional administrative privileges.

Remote Intrusion This type of hacking involves a intruder who attempts to penetrate a system remotely across the network. The intruder begins with no special privileges. There are several forms of this hacking. For example, a intruder has a much more difficult time if there exists a firewall on between him/her and the victim machine.

Note that Network Intrusion Detection Systems are primarily concerned with Remote Intrusion.

1.4 Why can intruders get into systems?

Software always has bugs. System Administrators and Programmers can never track down and eliminate all possible holes. Intruders have only to find one hole to break in.

1.4.1 Software bugs

Software bugs are exploited in the server daemons, the client applications, the operating system, and the network stack. Software bugs can be classified in the following manner:

Buffer overflows: Almost all the security holes you read about in the press are due to this problem. A typical example is a programmer who sets aside 256 characters to hold a login username. Surely, the programmer thinks, nobody will ever have a name longer than that. But a hacker thinks, what happens if I enter in a false username longer than that? Where do the additional characters go? If they hackers do the job just right, they can send 300 characters, including code that will be executed by the server, and voila, they've broken in. Hackers find these bugs in several ways. First of all, the source code for a lot of services is available on the net. Hackers routinely look through this code searching for programs that have buffer overflow problems. Secondly, hackers may look at the programs themselves to see if such a problem exists, though reading assembly output is really difficult. Thirdly, hackers will examine every place the program has input and try to overflow it with random data. If the program crashes, there is a good chance that carefully constructed input will allow the hacker to break in. Note that this problem is common in programs written in C/C++, but rare in programs written in Java.

Unexpected combinations: Programs are usually constructed using many layers of code, including the underlying operating system as the bottom most layer. Intruders can often send input that is meaningless to one layer, but meaningful to another layer. The most common language for processing user input on the web is PERL. Programs written in PERL will usually send this input to other programs for further evaluation. A common hacking technique would be to enter something like "| mail < /etc/passwd". This gets executed because PERL asks the operating system to launch an additional program with that input. However, the operating system intercepts the pipe '|' character and launches the 'mail' program as well, which causes the password file to be emailed to the intruder.

Unhandled input: Most programs are written to handle valid input. Most programmers do not consider what happens when somebody enters input that doesn't match the specification.

Race conditions: Most systems today are "multitasking/multithreaded". This means that they can execute more than one program at a time. There is a danger if two programs need to access the same data at the same time. Imagine two programs, A and B, who need to modify the same file. In order to modify a file, each program must first read the file into memory, change the contents in memory, then copy the memory back out into the file. The race condition occurs when program A reads the file into memory, then makes the change. However, before A gets to write the file, program B steps in and does the full read/modify/write on the file. Now program A writes its copy back out to the file. Since program A started with a copy before B made its changes, all of B's changes will be lost. Since you need to get the sequence of events in just the right order, race conditions are very rare. Intruders usually have to tries thousands of time before they get it right, and hack into the system.

1.4.2 System configuration

System configuration bugs can be classified in the following manner:

Default configurations: Most systems are shipped to customers with default, easy-to-use configurations. Unfortunately, "easy-to-use" means "easy-to-break-in". Almost any UNIX or WinNT machine shipped to you can be hacked in easily.

Lazy administrators: A surprising number of machines are configured with an empty root/administrator password. This is because the administrator is too lazy to configure one right now and wants to get the machine up and running quickly with minimal fuss. Unfortunately, they never get around to fixing the password later, allowing intruders easy access. One of the first things a intruder will do on a network is to scan all machines for empty passwords.

Hole creation: Virtually all programs can be configured to run in a non-secure mode. Sometimes administrators will inadvertently open a hole on a machine. Most administration guides will suggest that administrators turn off everything that doesn't absolutely positively need to run on a machine in order to avoid accidental holes. Note that security auditing packages can usually find these holes and notify the administrator.

Trust relationships: Intruders often "island hop" through the network exploiting trust relationships. A network of machines trusting each other is only as secure as its weakest link.

1.4.3 Password cracking

This is a special category all to itself.

Really weak passwords: Most people use the names of themselves, their children, spouse/SO, pet, or car model as their password. Then there are the users who choose "password" or simply nothing. This gives a list of less than 30 possibilities that a intruder can type in for themselves.

Dictionary attacks: Failing the above attack, the intruder can next try a "dictionary attack". In this attack, the intruder will use a program that will try every possible word in the dictionary. Dictionary attacks can be done either by repeatedly logging into systems, or by collecting encrypted passwords and attempting to find a match by similarly encrypting all the passwords in the dictionary. Intruders usually have a copy of the English dictionary as well as foreign language dictionaries for this purpose. They all use additional dictionary-like databases, such as names (see above) and lists of common passwords.

Brute force attacks: Similar to a Dictionary attack, a intruder may try all possible combinations of characters. A short 4-letter password consisting of lower-case letters can be cracked in just a few minutes (roughly, half a million possible combinations). A long 7-character password consisting of upper and lower case, as well as numbers and punctuation (10 trillion combinations) can take months to crack assuming you can try a million combinations a second (in practice, a thousand combinations per second is more likely for a single machine).

1.4.4 Sniffing unsecured traffic

Shared medium: On traditional Ethernet, all you have to do is put a Sniffer on the wire to see all the traffic on a segment. This is getting more difficult now that most corporations are transitioning to switched Ethernet.

Server sniffing: However, on switched networks, if you can install a sniffing program on a server (especially one acting as a router), you can probably use that information to break into client machines and trusted machines as well. For example, you might not know a user's password, but sniffing a Telnet session when they log in will give you that password.

Remote sniffing: A large number of boxes come with RMON enabled and public community strings. While the bandwidth is really low (you can't sniff all the traffic), it presents interesting possibilities.

1.4.5 Design flaws

Even if a software implementation is completely correct according to the design, there still may be bugs in the design itself that leads to intrusions.

TCP/IP protocol flaws: The TCP/IP protocool was designed before we had much experience with the wide-scale hacking we see today. As a result, there are a number of design flaws that lead to possible security problems. Some examples include smurf attacks, ICMP Unreachable disconnects, IP spoofing, and SYN floods. The biggest problem is that the IP protocol itself is very "trusting": hackers are free to forge and change IP data with impunity. IPsec (IP security) has been designed to overcome many of these flaws, but it is not yet widely used.

UNIX design flaws: There are number of inherent flaws in the UNIX operating system that frequently lead to intrusions. The chief problem is the access control system, where only 'root' is granted administrative rights.

1.5 How do intruders get passwords?

Intruders get passwords in the following ways:

Clear-text sniffing: A number of protocols (Telnet, FTP, HTTP Basic) use clear-text passwords, meaning that they are not encrypted as the go over the wire between the client and the server. A intruder with a protocol analyzer can watch the wire looking for such passwords. No further effort is needed; the intruder can start immediately using those passwords to log in.

Encrypted sniffing: Most protocols, however, use some sort of encryption on the passwords. In these cases, the intruder will need to carry out a Dictionary or Brute Force attack on the password in order to attempt decryption. Note that you still don't know about the intruder's presence, as he/she has been completely passive and has not transmitted anything on the wire. Password cracking does not require anything to be sent on the wire as intruder's own machine is being used to authenticate your password.

Replay attack: In some cases, intruders do not need to decrypt the password. They can use the encrypted form instead in order to login to systems. This usually requires reprogramming their client software in order to make use of the encrypted password.

Password file stealing: The entire user database is usually stored in a single file on the disk. In UNIX, this file is /etc/passwd (or some mirror of that file), and under WinNT, this is the SAM file. Either way, once a intruder gets hold of this file, he/she can run cracking programs (described above) in order to find some weak passwords within the file.

Observation: One of the traditional problems in password security is that passwords must be long and difficult to guess (in order to make Dictionary and Brute Force cracks unreasonably difficult). However, such passwords are often difficult to remember, so users write them down somewhere. Intruders can often search a persons work site in order to find passwords written on little pieces of paper (usually under the keyboard). Intruders can also train themselves to watch typed in passwords behind a user's back.

Social Engineering: A common (successful) technique is to simply call the user and say "Hi, this is Bob from MIS. We're trying to track down some problems on the network and they appear to be coming from your machine. What password are you using?" Many users will give up their password in this situation. (Most corporations have a policy where they tell users to never give out their password, even to their own MIS departments, but this technique is still successful. One easy way around this is for MIS to call the new employee 6-months have being hired and ask for their password, then criticize them for giving it to them in a manner they will not forget :-)

1.6 What is a typical intrusion scenario?

A typical scenario might be:

Step 1: outside reconnaissance The intruder will find out as much as possible without actually giving themselves away. They will do this by finding public information or appearing as a normal user. In this stage, you really can't detect them. The intruder will do a 'whois' lookup to find as much information as possible about your network as registered along with your Domain Name (such as foobar.com. The intruder might walk through your DNS tables (using 'nslookup', 'dig', or other utilities to do domain transfers) to find the names of your machines. The intruder will browse other public information, such as your public web sites and anonymous FTP sites. The intruder might search news articles and press releases about your company.

Step 2: inside reconnaisance The intruder uses more invasive techniques to scan for information, but still doesn't do anything harmful. They might walk through all your web pages and look for CGI scripts (CGI scripts are often easily hacked). They might do a 'ping' sweep in order to see which machines are alive. They might do a UDP/TCP scan/strobe on target machines in order to see what services are available. They'll run utilities like 'rcpinfo', 'showmount', 'snmpwalk', etc. in order to see what's available. At this point, the intruder has done 'normal' activity on the network and has not done anything that can be classified as an intrusion. At this point, a NIDS will be able to tell you that "somebody is checking door handles", but nobody has actually tried to open a door yet.

Step 3: exploit The intruder crosses the line and starts exploiting possible holes in the target machines. The intruder may attempt to compromise a CGI script by sending shell commands in input fields. The intruder might attempt to exploit well-known buffer-overrun holes by sending large amounts of data. The intruder may start checking for login accounts with easily guessable (or empty) passwords. The hacker may go through several stages of exploits. For example, if the hacker was able to access a user account, they will now attempt further exploits in order to get root/admin access.

Step 4: foot hold At this stage, the hacker has successfully gained a foot hold in your network by hacking into a machine. The intruder's main goal is to hide evidence of the attacks (doctoring the audit trail and log files) and make sure they can get back in again. They may install 'toolkits' that give them access, replace existing services with their own Trojan horses that have backdoor passwords, or create their own user accounts. System Integrity Verifiers (SIVs) can often detect an intruder at this point by noting the changed system files. The hacker will then use the system as a stepping stone to other systems, since most networks have fewer defenses from inside attacks.

Step 5: profit The intruder takes advantage of their status to steal confidential data, misuse system resources (i.e. stage attacks at other sites from your site), or deface web pages.

Another scenario starts differently. Rather than attack a specific site, and intruder might simply scan random internet addresses looking for a specific hole. For example, an intruder may attempt to scan the entire Internet for machines that have the SendMail DEBUG hole. They simply exploit such machines that they find. They don't target you directly, and they really won't even know who you are. (This is known as a 'birthday attack'; given a list of well-known security holes and a list of IP addresses, there is a good chance that there exists some machine somewhere that has one of those holes)

1.7 What are some common "intrusion signatures"?

There are three types of attacks:

reconnaisance These include ping sweeps, DNS zone transfers, e-mail recons, TCP or UDP port scans, and possibly indexing of public web servers to find cgi holes.

exploits Intruders will take advantage of hidden features or bugs to gain access to the system.

denial-of-service (DoS) attacks Where the intruder attempts to crash a service (or the machine), overload network links, overloaded the CPU, or fill up the disk. The intruder is not trying to gain information, but to simply act as a vandal to prevent you from making use of your machine.

1.8 What are some common exploits?

1.8.1 CGI scripts

CGI programs are notoriously insecure. Typical security holes include passing tainted input directly to the command shell via the use of shell metacharacters, using hidden variables specifying any filename on the system, and otherwise revealing more about the system than is good. The most well-known CGI bug is the 'phf' library shipped with NCSA httpd. The 'phf' library is supposed to allow server-parsed HTML, but can be exploited to give back any file. Other well-known CGI scripts that an intruder might attempt to exploit are: TextCounter, GuestBook, EWS, info2www, Count.cgi, handler, webdist.cgi, php.cgi, files.pl, nph-test-cgi, nph-publish, AnyForm, FormMail. If you see somebody trying to access one or all of these CGI scripts (and you don't use them), then it is clear indication of an intrusion attempt (assuming you don't have a version installed that you actually want to use).

1.8.2 Web server attacks

Beyond the execution of CGI programs, web servers have other possible holes. A large number of self-written web servers (include IIS 1.0 and NetWare 2.x) have hole whereby a file name can include a series of "../" in the path name to move elsewhere in the file system, getting any file. Another common bug is buffer overflow in the request field or in one of the other HTTP fields.

Web server often have bugs related to their interaction with the underlying operating system. An old hole in Microsoft IIS have been dealing with the fact that files have two names, a long filename and a short 8.3 hashed equivalent that could sometimes be accessed bypassing permissions. NTFS (the new file system) has a feature called "alternate data streams" that is similar to the Macintosh data and resource forks. You could access the file through its stream name by appending "::$DATA" in order to see a script rather than run it.

Servers have long had problems with URLs. For example, the "death by a thousand slashes" problem in older Apache would cause huge CPU loads as it tried to process each directory in a thousand slash URL.

1.8.3 Web browser attacks

It seems that all of Microsoft's and Netscape's web browsers have security holes (though, of course, the latest ones never have any that we know about -- yet). This includes both URL, HTTP, HTML, JavaScript, Frames, Java, and ActiveX attacks.

URL fields can cause a buffer overflow condition, either as it is parsed in the HTTP header, as it is displayed on the screen, or processed in some form (such as saved in the cache history). Also, an old bug with Internet Explorer allowed interaction with a bug whereby the browser would execute .LNK or .URL commands.

HTTP headers can be used to exploit bugs because some fields are passed to functions that expect only certain information.

HTML can be often exploited, such as the MIME-type overflow in Netscape Communicator's command.

JavaScript is a perennial favorite, and usually tries to exploit the "file upload" function by generating a filename and automatically hidden the "SUBMIT" button. There have been many variations of this bug fixed, then new ways found to circumvent the fixes.

Frames are often used as part of a JavaScript or Java hack (for example, hiding web-pages in 1px by 1px sized screens), but they present special problems. For example, I can include a link to a trustworthy site that uses frames, then replace some of those frames with web pages from my own site, and they will appear to you to be part of that remote site.

Java has a robust security model, but that model has proven to have the occasional bug (though compared to everything else, it has proven to be one of the most secure elements of the whole system). Moreover, its robust security may be its undoing: Normal Java applets have no access to the local system, but sometimes they would be more useful if they did have local access. Thus, the implementation of "trust" models that can more easily be hacked.

ActiveX is even more dangerous than Java as it works purely from a trust model and runs native code. You can even inadvertently catch a virus that was accidentally imbedded in some vendor's code.

1.8.4 SMTP (SendMail) attacks

SendMail is an extremely complicated and widely used program, and as a consequence, has been the frequent source of security holes. In the old days (of the '88 Morris Worm), hackers would take advantage of a hole in the DEBUG command or the hidden WIZ feature to break into SMTP. These days, they often try buffer overruns. SMTP also can be exploited in reconnaissance attacks, such as using the VRFY command to find user names.

1.8.5 Access
Failed login attempts, failed file access attempts, password cracking, administrative powers abuse

1.8.6 IMAP
Users retrieve e-mail from servers via the IMAP protocol (in contrast, SMTP transfers e-mail between servers). Hackers have found a number of bugs in several popular IMAP servers.

1.8.7 IP spoofing
There is a range of attacks that take advantage of the ability to forge (or 'spoof') your IP address. While a source address is sent along with every IP packet, it isn't actually used for routing. This means an intruder can pretend to be you when talking to a server. The intruder never sees the response packets (although your machine does, but throws them away because they don't match any requests you've sent). The intruder won't get data back this way, but can still send commands to the server pretending to be you.

IP spoofing is frequently used as part of other attacks:

SMURF
Where the source address of a broadcast ping is forged so that a huge number of machines respond back to victim indicated by the address, overloading it (or its link).

TCP sequence number prediction
In the startup of a TCP connection, you must choose a sequence number for your end, and the server must choose a sequence number for its end. Older TCP stacks choose predictable sequence numbers, allowing intruders to create TCP connections from a forged IP address (for which they will never see the response packets) that presumably will bypass security.

DNS poisoning through sequence prediction
DNS servers will "recursively" resolve DNS names. Thus, the DNS server that satisfies a client request will become itself a client to the next server in the recursive chain. The sequence numbers it uses are predictable. Thus, an intruder can send a request to the DNS server and a response to the server forged to be from the next server in the chain. It will then believe the forged response, and use that to satisfy other clients.

1.8.8 Buffer Overflows
Some other buffer overflow attacks are:
DNS overflow
Where an overly long DNS name is sent to a server. DNS names are limited to 64-bytes per subcomponent and 256-bytes overall.
statd overflow
where an overly long filename is provided

1.8.9 DNS attacks
DNS is a prime target because if you can corrupt the DNS server, you can take advantage of trust relationships.
DNS cache poisoning
Every DNS packet contains a "Question" section and "Answer" section. Vulnerable servers will believe (and cache) Answers that you send along with Questions. Most, but not all, DNS servers have been patched as of November, 1998.
DNS poisoning through sequence prediction & DNS overflow

1.9 What tools do intruders use to break into my systems?

1.9.1UNIX utilities
These utilities either come with your favorite UNIX platform or you can download them for free.

ping
to see if a host is alive.
traceroute
to find the route to the host
nslookup/dig
to discover all your DNS information
whois
finds out Internic registration information
finger
finds out who is logged in and info about users
rpcinfo
finds out what RPC services are running
showmount
display shares on a machine
SAMBA
displays info about WinNT SMB shares
telnet
the granddaddy of them all -- allows you to connect and play with any text-based protocol (HTTP, FTP, SMTP, etc.)

1.9.2 WinNT utilities

All of the UNIX utilities mentioned above can be used with WinNT. There are also some WinNT specific ones.
nbtstat
discovers NetBIOS information on remote machine
net view
is the LANMAN program that allows you to remotely view WinNT shares

1.9.3 Hacking-specific utilities

The standard toolkit for a intruder.
netcat
is characterized as a "TCP/IP" Swiss Army Knife, allows intruders to script protocol interactions, especially text-based protocols.
crack / NTcrack / L0phtCrack / etc.
that crack network passwords (Dictionary or Brute Force). These packages also contain utilities for dumping passwords out of databases and sniffing them off the wire.
Sniffing utilities
for watching raw network traffic, such as Gobbler, tcpdump, or even an honest-to-god Network Associates Sniffer© Network Analyzer
TCP and UDP port scanners
for scanning/strobing/probing which TCP ports are available. TCP port-scanners can also run in a number of stealth modes to evade/elude loggers.
Ping sweepers
for pinging large numbers of machines to see which ones are active.
Exploit packs
which are a set of one or more programs that know how to exploit holes on systems (usually, once the user is logged in).
Remote security auditors
such as SATAN that look for a number of well known holes in machines all across the network.
War dialers
that dial lots of phone numbers looking for dial-in ports.
NAT
is based upon the SAMBA code, and is useful for discovering NetBIOS/SMB info from Windows and SAMBA servers.
Scanners
are programs (like SATAN, ISS, CyberCop Scanner) that probe the system for vulnerabilities. That have a huge number of vulnerabilities they check for and are generally automated, giving the hacker that highest return for the minimal effort.

2.0 What are the pros/cons of setting up a system that can be hacked?

The three most commonly hacked servers on the net are unpatched systems running older Linux (like Red Hat 5.0), Solaris 2.6, and Microsoft IIS 4.0. Therefore, as part of your honeypot plan, you might want to setup one or all three of these systems.

Remember: if you put one of these systems on the Internet, within a month it will be discovered and hacked.

Pros:

Learn about incidence response
Most people believe "it can't happen to them", and are unprepared when it does. Setting up systems that hackers break into will teach you about how to detect hacker breakins and how to clean up after them.

Learn about hacking techniques
Watching hackers break into your system teaches you a lot about hacking.

If you need a secure system inside your company (for example, one that holds financial information), setup a similar system outside your company with bogus data. If a hacker compromises that system, you'll learn how to protect the one inside your company from similar exploits.

Early warning systems
Setting up servers inside your company that can easily be hacked will alert you to hostile activity long before real systems get compromised. Hackers try the simpler techniques first before moving on to harder ways of breaking into system. Therefore, setting up an easily hacked system will clearly indicate the hostile intent of somebody.

Cons:

Launching Point
The biggest danger is that somebody could use that system to launch further attacks against either you or other people. In particular, there might be legal considerations when a system you control attacks a third party.

and finally What are deception countermeasures?

Beyond honeypots in particular, you can setup "deception countermeasures". Your network "leaks" lots of information about itself, which hackers in turn use to break into your network. Therefore, if you leaks deceptive information about you network, then you'll at minimum misdirect your attackers, but hopefully trigger alerts.

I personally have done the following sorts of things:

E-mail headers
A classic problem on the web is that e-mail systems insert the IP address of the system sending the message to it. If you are inside a corporation and send e-mail out, you reveal internal e-mail servers. If you are using a free e-mail system like Yahoo mail or Hotmail, the IP address of the machine you used to send the mail is included in the header. This process can go several level deep as e-mail inside companies often travel several hops through gateway, firewalls, and anti-virus content scanners. It's difficult, but you can reprogram things in order to insert bogus IP addresses in to the headers.

DNS info
One of the first things a hacker will do against you is a DNS Zone Transfer. Many admins blocks access to TCP port 53 to stop this (though that breaks other DNS services). By inserting bogus machines or even entire bogus subdomains you misdirect the hacker. For example, I could setup a machine called "bogus.robertgraham.com" with an IP address of 192.0.2.132, then tell my IDS to trigger whenever it sees traffic to that address. Since my IDS already triggers on Zone Transfers, this'll catch somebody who is seriously trying to scope out my network.

anti-sniffers
Are you certain that your ISP isn't sniffing you? Well, in order to find out, setup machines elsewhere on the Internet to connect to some of your boxes using clear-text passwords. Then setup your IDS to trigger when anybody else uses those passwords. This is best used with a honeypot that doesn't have real services. For example, I've setup a virtual Telnet daemon on that another machines logs into every once-and-a-while. I've setup the IDS to trigger if anybody but that machine logs in using that account name. When they log in, they will soon find out it isn't real account.

anti-sniffers, part deux :P
Similar to above, you can transfer password files across the network that contain easily crackable passwords, then have the IDS trigger whenever anybody attempts to login. For example, setup a batch file that regularly transfers files via FTP, one of which is /etc/passwd. This will tell you if anybody has sniffed that file.

if you people have still got any more questions to ask you are free to mail me at my id : ajaykumar127@gmail.com

Check The Orkut Scraps without logging in !!!


It all began on a lazy afternoon , when i came across this news that orkut can be hacked :P I started to do get some information on this , and soon found out the thing . Then i thought that, i will build a small application which can do so. Thanks to the support by few friends online and along with that my small dwelling flash i have made a small application that allows you to read ORKUT scraps just by knowing the UID ( which is shown in the scrap book , as shown in image below ).








This thing mainly works because of a thing that is at core doing the act.

Here's the Screenshot of the THING.


















To know more details about how this thing came about ...you know whom to contact.

If you need my app , just mail me : ajaykumar127@gmail.com with subject "NEED ORKUT Scrap Viewer" .I'll get back to you.

regards...
ajay

Intel Builds 80-Core, 1-Trillion Calcs Per Second Prototype Chip

A typical 80 core processor

A typical Motherboard socket for the 80 core processor

What's cool: Performing 1 Trillion calcs per second, the chip could do the same number crunching that 10 years ago took up 2,000 square feet of machinery to do. Instead of the half-megawatt of juice, it could take as little as 62 watts. The chips has 80 cores.

What sucks?: Five years, at least, till these are available. No x86 architecture version yet, even in prototype. And optimizing programs that to take advantage of eighty cores is still a very hard thing to do. Multiple core processing is still best for mass rote operations like those involving math and video.

Intel's researchers have produced an 80-core chip that uses less energy than a quad-core processor and has teraflop performance capabilities.

Researchers have built the prototype to study how best to make that many cores communicate with each other. They're also studying new designs for cores and new architectural techniques, according to Manny Vara, a technology strategist with Intel's R&D labs. The chip is just for research purposes and lacks some necessary functionality at this point, but Vara says Intel will be able to produce a chip with 80 cores in five to eight years.

The chip is being called the Tera-Scale Teraflop Prototype. Intel is planning on releasing specifics about the research project at the 2007 International Solid State Circuits Conference in early February.

Since dual-core and quad-core chips were just introduced to the market in the past year, looking forward to an 80-core chip is a major departure from the expected natural progression in microprocessors.

This is being done as a test, The scientists came up with all these different ideas and there is a need to test them on a piece of silicon. The only thing is about the uncertainity regarding if it works till a working model is built and then tested the heck out of it.

The 80-core chip uses less than 100 watts of energy; a dual-core chip uses 60 to 70 watts and a quad-core uses 105 to 130 watts. Of course the numbers for the 80-core chip could be affected by the fact that it's lacking some functionality, but it's still a significant accomplishment.
I can call this as Intel's research project thus by far "revolutionary."



It showcases a focus on power efficiency and keeping things within a power and thermal envelope, they recognize that they can't generate any more heat or pull more power or they'll just become power hogs. With that large a number of cores, it's significant they can get it down below 100 watts. So this is pretty impressive. Real impressive.

They're different kinds of cores, and energy efficiency is a major part of the research project. If you look at it, by the time you put dozens of cores on a chip, they won't be the same kind that you can put three or four on a chip today. The new ones will be much simpler. You break the core's tasks into pieces and each task can be assigned to a core. Even if the cores are simpler and slower, you have a lot more of them so you have more performance.


Here i note that the power efficiency lies in the new, simpler cores.

Think more-complex four cores compared to simpler 80 cores. Each of those four cores can do more individually than one of the 80,But with an 8-core chip you will get a lot more performance and lower power because you have a lot of them running at lower speed. You're only using the cores you need. It's performance on demand. If you need more performance, it wakes up more cores, and when you're done, they go back to sleep."

With that many cores, Intel is able to design what is called "core hopping." If one part of the chip gets hot, the work that those particular cores are doing is moved to other cores on another part of the chip. That, will lower the heat being generated.

This's definitely exciting, as they're pushing the boundaries out in terms of how many cores they can squeeze onto a chip. It's about the horizontal scalability of cores on a single chip. They're relatively dumb and unsophisticated cores, but the experiment is how can they do it. How many can they pack in and still work together and communicate with each other?

Part of the challenge with building a chip with so many cores has been to design a communication network so that they all can communicate with each other.

Handling that much network traffic has been quite a task, and the chip will be just slightly larger than the average chip today. What they are doing is designing a network inside the chip. Today, you hear about high-performance computing and they have these big, fat super-powerful servers and they're all networked together. They are trying to basically do that, but on a chip. How do you bring a real network inside a chip so all the cores can talk to each other?.

At work they are quite literally creating a network mesh to let each little core communicate with the other cores and the rest of the system, the cores will want to know what the other cores will doing so they don't fight.

While it may take five to eight years to come out with a working 80-core chip, IT managers might start watching for what he calls "different flavors" of quad-core chips. Maybe you'll have interim chips where they have more complex cores along with simpler cores, too.

The bottom line: Congrats on the teraflop chip, Intel, but wake us up when this baby is for sale.
The Verdict: Vaporous CPU,solid PR move by Intel.

words of interest by...
ajay.

How Does Bit Torrent Work ?






















BitTorrent is the name of a client application for the torrent peer-to-peer (P2P) file distribution protocol. created by programmer Bram Cohen. BitTorrent is designed to widely distribute large amounts of data without incurring the corresponding consumption in server and bandwidth resources (and typically, monetary fees attracted as a result of that).

The original BitTorrent application is written in Python and its source code has been released under the BitTorrent Open Source License (a modified version of the Jabber Open Source License), as of version 4.0. The name "BitTorrent" refers to the distribution protocol, the original client application, and the .torrent file type.

The bittorrent protocol breaks the file(s) down into smaller fragments, typically a quarter of a megabyte (256 KB) in size. Peers download missing fragments from each other and upload those that they already have to peers that request them. The protocol is 'smart' enough to choose the peer with the best network connections for the fragments that it's requesting.

To increase the overall efficiency of the swarm (the ad-hoc P2P network temporarily created to distribute a particular file), the bittorrent clients request from their peers the fragments that are most rare; in other words, the fragments that are available on the least number of peers, making most fragments available widely across many machines and avoiding bottlenecks.

The file fragments are not usually downloaded in sequential order and need to be reassembled by the receiving machine. It is important to note that clients start uploading fragments to their peers before the entire file is downloaded.

Sharing by each peer therefore begins when the first complete segment is downloaded and can begin to be uploaded if another peer requests it. This scheme is particularly useful for trading large files such as videos and operating systems. This is contrasted with conventional file serving where high demand can lead to saturation of the host's resources as the consumption of bandwidth to transfer the file to many requesting downloaders surges.

With BitTorrent, high demand can actually increase throughput as more bandwidth and additional “seeds” of the file become available to the group. Cohen claims that for very popular files, BitTorrent can support about a thousand times as many downloads as HTTP.

BitTorrent-etiquette

Because BitTorrent relies on the upstream bandwidth of its users — and the more users, the more aggregate bandwidth is available for sharing the files — it is considered good etiquette to leave one's BitTorrent client open after downloading has completed so that others may continue to gain from the file that has been distributed.

It is not clear, however, how long one should leave their client open after downloading has finished. Many clients report the byte traffic upstream as well as down, so the user can see how much they have contributed back to the network. Some clients also report the "share ratio", a number relating the amount of data uploaded to the amount downloaded. It is generally considered good form to at least share back the equivalent amount of traffic as the original file size.

It is worth noting that the requirement of a "1.00" share ratio (uploading as much data as you have downloaded) is rather hotly contested given its relative impossibility to achieve for every person. On any given torrent, the best possible outcome is the original seeder with an infinite ratio (having only uploaded data and never downloaded any data), a number of peers with 1.00 ratios (having downloaded the file, uploaded just as much data, and then promptly logged off), and two users with a .50 ratio (the last two having each downloaded a separate half of the file and then shared their half with the other). This is highly unlikely to be achieved due to the very small chance of the last two peers downloading completely opposite halves and finishing just as the last seeder logged off and the fact that not all people will upload the same amount of data they downloaded as some will upload less and others will upload more. Ultimately, a perfect torrent would leave two end users with only a .50 ratio for the torrent, which means every user would have to provide new content at least equal to the portion of data they did not get to upload in the last torrent to maintain an overall ratio of 1.00.

While it's highly unlikely that all users who download a given torrent will achieve a 1.0 ratio on it (because the net ratio of all users is 1.0, if any user uploads past 1.0 some other user will have to sustain a lower ratio), it is more of a guideline to encourage the average upstream of a given network. Some networks, for example, prevent access to new torrents for the first 24-48 hours that the torrent is active to people with overall ratios of less than 1.0 and a certain amount of data uploaded.

The amount of time the client is left open may be more important than the amount of traffic contributed, since new users attempting to download a file will first need to find peers hosting the file.

Many advanced trackers now track statistics such as how many seeders and downloaders were on a torrent at the time of a user's disconnect as many consider this information more important than just the user's ratio of downloaded/uploaded.

For any more clarifications and doubts do mail me at : ajaykumar127@gmail.com


regards..
ajay

The Day Vista came onto my PC












It was not so long that i saw my new vista coming back to life.
All i remember is it was a lazy afternoon in the mid of my holidays after the 5th
semester @ college , and it's like this new thing is just come to my mind. So i decided to give it a try .As you might have seen the screen shot above from my desktop , i hereby want to write say about 10 features which i liked in Vista the most , here they go :

Top 10 Favorite New Features

From the core to the cosmetic, there's a lot to like in Vista.

1. Improved security. Running as a standard user with limited permissions is finally practical. With User Account Control, even administrators operate with reduced-privilege credentials and have to verify attempts to "escalate"—in other words, to execute commands that could expose the OS to danger.

2. New Start menu. With integrated search, you can type in a path—such as C:\Users\John—to launch Windows Explorer there, or simply start typing in a program or filename.

3. Internet Explorer 7. It may not be as good as Firefox or Opera, but it's a big improvement over IE6. Sure, we groused about the lack of tabs—but they're finally here.

4. New Windows Explorer. Explorer makes file navigation easier, with breadcrumbs that let you jump to a specific level in the directory hierarchy, integrated search, live icons that show both a visual preview of a document and the app that it opens in, and buttons that make it easy to perform common context-­appropriate tasks.

5 .Live views of application windows. Press Windows-Tab to get this "Flip 3D" view, or Alt-Tab for a 2D view. Either way, task switching is clearer.

6. Faster, image-based installation process.

7. Improved backup, including full-disk imaging.

8. Ad hoc collaboration with Windows Meeting Space.

9. Mobility Center, it's the Best bet!!

10. New Reliability and Performance Monitor, Task Scheduler, and Event Logs

so just go and grab you copy!!!!

Invisibility Cloaks Working



Optical-camouflage technology developed at the University of Tokyo

This seems perfectly believable when you're reading about a fictional world filled with witches, wizards and centuries-old magic; but in the real world, such a garment would be impossible, right? Not so fast. With optical-camouflage technology developed by scientists at the University of Tokyo, the invisibility cloak is already a reality.

Optical camouflage delivers a similar experience to Harry Potter's invisibility cloak, but using it requires a slightly more complicated arrangement. First, the person who wants to be invisible (let's call her Person A) dons a garment that resembles a hooded raincoat. The garment is made of a special material that we'll examine more closely in a moment. Next, an observer (Person B) stands before Person A at a specific location. At that location, instead of seeing Person A wearing a hooded raincoat, Person B sees right through the cloak, making Person A appear to be invisible. The photograph on the right below shows you what Person B would see. If Person B were viewing from a slightly different location, he would simply see Person A wearing a silver garment (left photograph below).

So What is Optical Camouflage?

Optical camouflage is a kind of active camouflage.

This idea is very simple. If you project background image onto the masked object, you can observe the masked object just as if it were virtually transparent.

This shows the principle of the optical camouflage using X'tal Vision. You can select camouflaged object to cover with retroreflector. Moreover, to project a stereoscopic image, the observer looks at the masking object more transparent.

Optical camouflage can be applied for a real scene. In the case of a real scene, a photograph of the scene is taken from the operatorfs viewpoint, and this photograph is projected to exactly the same place as the original. Actually, applying HMP-based optical camouflage to a real scene requires image-based rendering techniques.

though this technology appears as a remarkable invention this can easily misused.however we all are looking forward to buy this piece of clothing.......

regards..
ajay